Compositions and Methods for Electrolytic Cleaning of a Material
Compositions and methods are provided for electrolytic cleaning of a material. Compositions and methods include electrochemical modification of a carrier fluid tailored for the removal of a target contaminate from the material. Compositions and methods can include booster compounds and modified pH for enhanced cleaning capacity.
Latest WOODY AMERICA LLC Patents:
This invention relates to advanced electrolytic cleaning compositions and methods by which pollutants, contaminants and pathogens are removed from surfaces. Embodiments include providing environmentally preferred cleaning and disinfecting materials. The scope of this technology includes the means (instrumentation, methodologies, and formulations) for delivering these materials. Further, the addition of biodegradable, environmentally preferable cleaning booster(s) can be diluted into the charged fluid(s) conveniently at the point of use embodiments herein to replace and/or augment the use of traditional cleaning chemicals. The adoption of this novel approach delivers superior environmental hygiene for personal and public use while having minimal impact on the balance of the natural environment.
BACKGROUND OF THE INVENTIONSince the dawn of civilization where people have congregated in communal groups there has been a need to maintain personal, public, and environmental hygiene. Early civilizations determined that open sewage and poor personal hygiene lead to horrific pathogenic outbreaks. These lessons taught the need to clean our personal and public environments, and to destroy the invisible killers, pathogens such as bacteria, fungi, molds, and viruses. Currently most human contact with surfaces is cleaned with a variety of aqueous chemical solutions each with various degrees of effectiveness, toxicity and environmental impact. As the value of these conventional chemical solutions increases we are left to their fate in the environment.
Research over time has shown that continually increasing levels of these chemical residues are responsible for a wide variety of environmental problems including toxic and mutagenic effects to local fauna and flora, particularly in aquatic ecosystems.
Traditional cleaning methods typically utilize a soap and water approach. A soap or surfactant is dissolved into water to create a solution which causes fats, grease, and oils to become miscible, or semi soluble, in water. The mechanism is to dissolve an amphiphilic molecule, which has a polar “head” or hydrophilic region and a non-polar “tail” or hydrophobic region, into an aqueous solution. The hydrophobic region of the molecule is soluble in the non-polar fat, grease, or oil contaminants, while the polar hydrophilic region of the molecule is exposed to the surrounding aqueous solvent. As these amphiphilc molecules dissolve into the aqueous medium, micelles are formed once the critical micelle concentration (CMC) is reached. When micelles form in water, their tails form a core that can encapsulate an oil droplet, and their (ionic/polar) heads form an outer shell that maintains favorable contact with water. This mechanism essentially makes fats, grease and oils soluble in water, also known as emulsification. Once emulsified, the contaminant material is easily rinsed away with the solvent stream into the waste effluent.
In addition, many cleaners utilize organic solvents to remove adhesives, petroleum residues, and a wide variety of other contaminants. The underlying principle is the same as for soap/water in that the mechanism is to make the contaminant soluble so it can be dissolved away from the surface and held in the solvent stream so it can then be rinsed away into the waste effluent.
Traditionally, concentrated cleaning chemicals rely on a dispenser or apparatus for injection and dilution of a chemical concentrate into an influent water stream which is then made available for use at a predetermined concentration. One problem with this approach is that most of these chemical concentrates are very toxic until they are diluted prior to use. This certainly is an issue upon accidental personal contact with these compounds as many will cause severe eye, skin, and/or mucous membranes irritation. Chemical concentrates and their dilutants over time will continue to contribute an ever increasing molar mass in the environment where their intermediate or final fate is not clear. Indeed, as the number of concentrates increases in different cleaning tasks there is the ever present danger of cross chemical reactions which not only complicate the task of determining their final fate in the environment but may provide dangerous sources of chemical exposure not previously anticipated.
It has also become abundantly clear that transportation expenses make up an ever increasing portion of the cost for any salable item. At some point, cost of fuel needed to deliver cleaning chemicals to the point of use will become cost prohibitive.
If effective cleaning and sanitizing chemicals could be produced at the place where they are needed, provided the raw materials are readily available, it would represent a great reduction in the current cost structure involved with procuring and using manufactured chemicals. If these materials could be produced using raw materials which are safe for the environment and safe for the personnel completing the cleaning tasks it would represent significant advancement in the state-of-the-art.
Against this backdrop the present invention has been demonstrated to solve the above-described problems and further a technical advance is achieved in the field by the present Compositions and Methods for Electrolytic Cleaning of a Material as described herein.
BRIEF SUMMARY OF THE INVENTIONThe above-described problems are solved and a technical advance achieved in the field by the present Compositions and Methods for Electrolytic Cleaning of a Material, or “the ElectroCleaning Process”. One important component of surface cleaning is the ability to break the electrostatic bonds that attract and hold contamination onto various surfaces by controlling de-adsorption, absorption, capillary pressure, ζ-potential (U.S. Pat. No. 1,199,472, Sep. 26, 1916, Isaac H. Levin; Electrolytic Apparatus; U.S. Pat. No. 1,374,976, Apr. 19, 1921, Herbert I. Allen and Kent R. Fox; Electrolytic Cell; U.S. Pat. No. 3,334,035, Aug. 1, 1967, Jule N. Dews and George J. Harris, United States of America; Process for sterilization with nascent halogen; U.S. Pat. No. 3,361,663, Jan. 2, 1968, William Bruce Murray and John W. Christensen); Sanitizing System, and other surface active forces. As described herein, embodiments of the invention are directed at altering the electrochemical state of a substrate component and changing the ζ-potential at the solid-liquid interface, solid-solid interface, liquid-liquid interface, and/or contaminant-substrate interface by a carrier fluid. As described herein, the carrier fluid is electrochemically altered prior to utilization by the addition or removal of electrons from the fluid system depending on the nature of the application. This electrochemical alteration process of the carrier fluid is both flexible and controllable by various methods and iterations of instrumentation employed.
Embodiments of the present invention act directly on the electrochemical charge balance between the solid-liquid/solid-solid interface to reversibly alter the electrochemical potential and overcome the technical impediments to efficiently clean a surface. The charged fluids generated, as described herein, directly modify the electrochemical properties of the contaminants to facilitate release of the contaminants and increase cleaning efficiency by controlling and overcoming the electrochemical charge that trapped, fixed, or adsorbed, the contamination in place. Embodiments of the present invention utilize the electrochemical state of a carrier fluid to address variations in bonding potential, and release the fluid and contaminants for improved and or selective cleaning efficiency. Easy manipulation of electronic potentials allows for utility to create a product that can be tailored to remove a wide range of pollutants that are attracted, and adsorbed, by varying electrostatic forces, A properly adjusted charged carrier fluid will remove pollutants and prevent their reattachment (re-adsorption) to the surface being cleaned.
In one aspect, embodiments of the invention use traditional cleaning application and waste recovery equipment as a method for delivery, removal and rinse of the contaminants in the electrochemically altered fluid that delivers a charge to a given surface to remove the contaminants. Enhancement of wettability, creation of micelles and the sequestration of pollutants can be invoked by the addition of various materials to the charged fluids to assist in the cleaning and sanitation process. These materials may include alkyl glucosides, alcohol ethoxylates, humic/fulvic acids and/or combinations of theses materials and/or other compounds.
Embodiments of the invention include control of the electrochemical state of a surface by electrochemically altering a carrier fluid prior to its application onto the surface. The electrochemically altered carrier fluid can use either a negative, or reducing potential (excess of electrons), or a positive, or oxidizing potential (lack of electrons), and the amount of charge can be adjusted to control removal of a wide variety of fats, grease, oils, and other contaminants. In one embodiment a split cell electrolysis device generates both solutions from the split stream exiting the electrolysis subsystem.
Electrolysis of water with various enhancements has been understood since 1834 when Michael Faraday completed experiments which led to what is known as Faraday's laws of electrolysis. There are a wide variety of electrolytic apparatus designs which produce useful charged fluids. Examples of electrolysis subsystems are demonstrated in U.S. Pat. No. 1,199,472, Sep. 26, 1916, U.S. Pat. No. 1,374,976, Apr. 19, 1921, and U.S. Pat. No. 1,799,116, Mar. 31, 1931, each incorporated by reference herein for all purposes.
Embodiments herein include controlling the electric potential of a solution by adjusting current density, total dissolved solids (TDS) and constituents, electrode size and type, membrane type, electric current, voltage, fluid dwell time, or a combination of any of these or other variables. This allows a user to “tailor” a cleaning fluids' electric potential so as to maximize efficiency for use on the task at hand. Embodiments of the present invention also provide predetermined compositions readily available at a filling port, e.g., to refill a squirt bottle with glass cleaner. Other embodiments provide a control at a user interface which can be used to “dial-in” a cleaner, pre diluted within the system, to provide a cleaning material tailored for the task at hand.
Further, embodiments of the present invention generate powerful oxidizing fluids utilizing a variety of materials. The oxidation strength of the fluid can be modified as needed depending on the application requirement. Traditionally chlorine, or a chlorinated compound, is typically used as a disinfectant due to availability, cost and utility, (has been proven to kill 99% of the organisms and pathogens that cause disease and illness). Chlorine, oxygen, ozone, and even quaternary ammonium compounds are all chemicals used as oxidizers to remediate biological contaminants. These compounds oxidize, or “steal”, electrons from the cell wall of biologic substances thereby making them effective sanitizers. In terms of microbial action, an oxidizer pulls electrons away from the pathogenic cell membrane causing it to become destabilized and leaky. Destroying the integrity of the cell membrane leads to rapid cell death. Oxidizers then continue to oxidize, or “burn” up, the biologic remains leaving simplified organic residues which are no longer pathogenic and harmlessly rinsed away into the waste effluent. For this reason, oxidizers are also effective at killing viral pathogens as well. An effective chlorine oxidizer in a chlorine sanitizer is hypochlorous acid, HOCl. As such, embodiments herein include oxidizing cleaning and/or sanitization fluid having a tailored electric potential.
It is useful to understand the actual mechanism which affects the death of these pathogenic organisms, although the Applicant does not wish to be bound to any particular theory. The chlorine atom (or other like atom) pulls electrons from the hypochlorite molecule becoming a chloride ion and leaving an oxygen free radical which is the chemical species actually oxidizing the cell wall of the pathogenic organism being disinfected. Although it is the oxygen free radical doing the work, we measure the disinfectant as chlorine because it is a simple odor test to tell if it is present. It is chlorines ability to pull an electron from the oxygen atom producing an oxygen free radical which makes the hypochlorous acid species so effective.
In other embodiments herein, additives or boosters are added to the electrolyzed solution to facilitate creation of a micelle, in combination with a controlled oxidation potential. This approach provides a unique sanitization method that is adjustable allowing for effective sanitization of both anaerobic and aerobic organisms.
Embodiments of the invention also include adjustment and control of the carrier fluid pH, eH, and/or redox potential to improve efficiency of the disinfection process. As the reducing potential of compositions increase, a greater pH of the carrier fluid is required. Conversely, the lower the reducing potential (increased oxidizing potential) used, typically the lower the pH of the carrier fluid required. Using an appropriately charged fluid in conjunction with other components, added to address specific removal requirements, significantly improves contaminant removal efficiency.
Post injection of various cleaning boosters, surfactants, sequestering agents and/or other compounds to adequately address various aspects of the mechanisms required for cleaning is readily accomplished herein. The addition of cleaning boosters may be required to address and assist capillary penetration where contaminants are entrapped by imbibition of the contaminant into the texture and micro-pores of the surface being cleaned. Boosters may be used to reduce surface tension or increase the wetting phase wettability thus creating a low contact angle at the solid-liquid interface. This allows the wetting phase to penetrate into subsurface capillaries, and deliver the charge from the electrochemically altered fluid to satisfy and release the electrostatic bonding potential of the contaminant.
Embodiments herein provide for the enhancement of wettability, creation of micelles, and the sequestration of pollutants engineered by the addition of various materials to the charged fluids to assist in the cleaning and sanitation process. These materials may include alkyl glucosides, alcohol ethoxylates, humic/fulvic acids or combinations of theses materials and/or other like compounds. This combination of cleaning and sanitizing solutions can then be dispensed conveniently at the point of use for example by uses as described in patent application 60/913,287 or other means familiar to one skilled in the art. U.S. Patent Application No. 60/913,287 is incorporated by reference in its entirety.
Finally, compositions and methods disclosed herein control the electrochemical state of a treated surface without the introduction of expensive, complex, or toxic synthetic chemicals thus reducing overall cost and logistical requirements. By providing compositions and methods herein for cleaning or sanitizing a surface we can create a means or apparatus utilizing compositions and methods to produce safe cleaning and disinfecting materials on site, conveniently at the point of use. Using embodiments of the present invention we can maintain the hygiene of our personal and public environments in a sustainable way without sacrificing the natural balance and health of the global environment. This unique and unexpected approach allows for environmentally friendly cleaning to be conducted safely, utilizing the molecular mechanisms which hold contaminants to the surfaces people come into contact with every day at a lower cost than current conventional methods thus significantly advancing the state-of-the-art.
These and various other features and advantages of the invention will be apparent from a reading of the following detailed description and a review of the appended claims.
Embodiments of the present invention provide cleaning solutions that are designed to effectuate the convenient release of contamination from a wide range of surfaces, e.g., any exterior boundary of any material requiring cleaning, including wood, metal, plastic, and granite. Additionally, other aspects of the invention provide sanitizing agents by inclusion of various chemical components to produce highly oxidizing fluids. One such example of a chemical component used herein is described by Kaestner et al, U.S. Pat. No. 3,819,329, 1974 incorporated by reference herein, for all purposes.
The ability to manipulate potential of a solution allows for utility to create a product tailored to remove a wide range of pollutants or other substances that are attracted by electrostatic forces. A properly adjusted charged carrier fluid will remove pollutants and prevent their reattachment to the surface being cleaned. The removal and dispersal of pollutants into the carrier fluid without re-attraction to the surface is necessary for effective decontamination.
The enhancement of wettability, creation of micelles and the sequestration of pollutants can be invoked by the addition of various materials to the charged fluids to assist in the cleaning and sanitation process. These materials may include alkyl glucosides, alcohol ethoxylates, humic/fulvic acids and/or combinations of theses materials and/or similar compounds.
The characterization of an Advanced Cleaning Mechanism can be described by offsetting the electrostatic charge, or zeta potential (ζ-potential), U.S. Pat. No. 1,199,472, Sep. 26, 1916, Isaac H. Levin; Electrolytic Apparatus; U.S. Pat. No. 1,374,976, Apr. 19, 1921, Herbert I. Allen and Kent R. Fox; Electrolytic Cell; U.S. Pat. No. 3,334,035, Aug. 1, 1967, Jule N. Dews and George J. Harris, United States of America; Process for sterilization with nascent halogen; U.S. Pat. No. 3,361,663, Jan. 2, 1968, William Bruce Murray and John W. Christensen; Sanitizing System), which is a measure of the force which attracts or repels a disparate material to or from a surface. These mechanisms and their effects on surface cleaning represent a significant advance in the state-of-the-art. When a food or dirt residue, i.e. contaminant, is splashed or spilled onto a surface it is applied by some force, which for example is gravity in the case of spills, to a surface alone and parallel to the ground; the floor for example. The residue is merely applied to the contaminated surface and has not been physically ground into the surface or chemically transformed into part of the chemical structure of the surface. A liquid drop can remain stuck on a tilted plane, despite gravity, if the contact angle is different at the front and at the rear of the drop (contact angle hysteresis), (U.S. Pat. No. 3,836,448, Sep. 17, 1974, Pierre Bouy and Daniel Collard; Frames for electrolytic cells of the filter press type).
Capillary forces oppose gravity due to an attraction to the solid surface. This attraction is related to the surface tension, the liquid density, volume of the drop, and the contact angle on the plane, measured counter-clockwise. The capillary pressure is given by:
where r and r′ are the principal radii of curvature of the interface and γ12 is the specific free energy of the interface. When two immiscible fluids are in contact with a solid surface, the fluid-fluid interface intersects the solid at the contact angle θ, given by Young's equation, (U.S. Pat. No. 3,836,448, Sep. 17, 1974, Pierre Bouy and Daniel Collard; Frames for electrolytic cells of the filter press type),
where λs1 is the specific free energy of the interface between the solid and liquid 1, λs2 the specific free energy between the solid and liquid 2, and λ12 the specific free energy between the two liquids, 1 and 2.
A common example of this phenomenon is a raindrop falling down a car windshield, U.S. Pat. No. 3,836,448, Sep. 17, 1974, Pierre Bouy and Daniel Collard; Frames for electrolytic cells of the filter press type). If a drop of oil is splashed onto a wall it will slowly run down the wall due to the effects of gravity. As the oil runs down the wall a trail of the oil material is left behind which traces the path of the oil drop as it flows down the wall. The oil drop leaves some material adhered or adsorbed to the wall surface instead of running off the wall as the integrated drop which hit the surface initially. This effect is due to the electrostatic attraction of oppositely charged regions of the contaminant material for the surface it is applied to. As the drop runs down the wall particles of the oil are electrostatically attracted to the surface.
This attraction is greater than the van der Waals attraction the “stuck” particle has for the other particles in the source drop. This attraction holds the particle to the surface while the rest of the particles in the drop continually sheer away from each other until all the mass of the drop is attracted to the surface. Embodiments of the present invention modify the condition of these electrostatic forces thus allowing the material to in effect be released from the surface being cleaned. This effect can be characterized by understanding the ζ-potential. The ζ-potential is widely studied in the field of colloidal dispersions and used to predict the stability of particle suspensions and their tendency to agglomerate. The ζ-potential is a relative measure of the stability of a system of dispersed colloidal particles.
The DLVO theory, U.S. Pat. No. 3,390,065, Jun. 25, 1968, Hal B. H. Cooper; Process and cell for the manufacture of either sodium hypochlorite or chlorine, for colloidal interactions) dictates that a colloidal system will remain stable if and only if the coulombic repulsion, arising from the net charge on the surface of the particles in a colloid is greater than the van der Waals force between those same particles. When the reverse is true, the colloidal particles will cluster together and form flocculates and agglomerates (depending on the strength of the van der Waals attraction and the presence or absence of steric effects). Since the higher the absolute ζ-potential, the stronger the coulombic repulsion between the particles, and therefore the lesser the impact of the van der Waals force on the colloid. The ζ-potential, also known as the electrokinetic potential, originates from this accumulation of electrical charges at a solid/liquid interface. The electrostatic potential generated by the accumulation of ions at this interface is organized into an electrical double-layer, consisting of the Stern layer and the diffuse layer.
Suspending a charged particle in an aqueous solution will cause a counter ion cloud, consisting of the Stern or Helmholtz layer and the diffuse or Gouy-Chapman layer, which surrounds the particle's surface charge to compensate for the charge potential, or electrokinetic difference. A decrease of potential can be linear or exponential, depending on the spatial distribution of counter ions. The decrease is linear in the case of a regular distribution of counter ions and exponential in the case of irregular distribution with a decreasing number of counter ions with increasing distance. The outer Helmholtz layer therefore involves a linear potential decrease, while the Gouy-Chapman layer involves an exponential potential decrease. Contrary to the ion fixed Stern layer, the diffuse layer consists of movable ions. During the diffusive movement of a particle, part of the diffuse ion layer is being removed. Because of the loss of counter ions, the particle is now charged towards the exterior. When a voltage is applied to a solution, the potential at this slipping plane becomes the ζ-potential.
Embodiments of the present invention can be used to variably modify the shear plane (slipping plane) which is an imaginary surface separating the thin layer of liquid bound to the solid surface and showing elastic behavior from the rest of the liquid showing normal viscous behavior. If all the particles have a large negative or positive ζ-potential they will repel each other and there is dispersion stability. If the particles have low ζ-potential values then there is no force to prevent the particles coming together and there is dispersion instability or agglomeration. For example, a dividing line relative to the system between stable and unstable aqueous dispersions is generally assumed to be greater than a +30 or −30 mV ζ-potential, (U.S. Pat. No. 1,799,116, Mar. 31, 1931, J. E. Noeggerath; Electrolytic Apparatus; U.S. Pat. No. 3,390,065, Jun. 25, 1968, Hal B. H. Cooper; Process and cell for the manufacture of either sodium hypochlorite or chlorine). Particles with ζ-potential more positive than +30 mV are normally considered stable. Particles with ζ-potential more negative than −30 mV are normally considered stable.
When the ζ-potential is close to zero, the coagulation (formation of larger assemblies of particles) is very fast and this causes fast sedimentation. Even when the surface charge density is very high but the ζ-potential is low, the colloids are unstable. Also the velocity of heterocoagulation (coagulation of different particles) depends on the ζ-potentials of both kinds of particles. Therefore, the ζ-potential is an important parameter characterizing colloidal dispersion.
Besides the characterization of colloidal dispersions the ζ-potential is of high importance for understanding the behavior of macroscopic solids in many technical applications. As an indicator for surface charge the ζ-potential gives information about adsorption or adhesion processes, the existence of acidic and basic surface groups, and related properties, (U.S. Pat. No. 3,640,804, Feb. 8, 1972, Chemech Engineering Ltd.; Method for conducting electrolyte to, from, and through an electrolytic cell). As an interfacial characteristic, the ζ-potential is hence influenced by the properties of a solid surface and the surrounding liquid. In effect the surface to be cleaned can be characterized as the area where we will induce a Stem or non mobile layer to this system. Embodiments of the present invention typically remove a material from a surface by applying a ζ-potential to the system great enough to overcome the van der Waals forces attracting the contaminant to that surface. The charge may also be imparted to the contaminant particles, not only inducing a loss of attraction for the surface, but actually causing a contaminant particle to be repelled from the surface and other contaminant particles, thus creating dispersion which allows the contaminant to be rinsed away with the solvent flow.
The cleaning compositions of the invention may be of any nature and preferably of one or more charged fluids which can be used for a variety of general cleaning tasks. These charged fluids may be produced chemically or in the preferred embodiment by electrolysis of water with some enhancement added to the production stream. In some embodiments the charged fluids include all purpose cleaning materials, some cleaning tasks may require the introduction of cleaning boosters to enhance the contact angle of the fluid (wettability) and thus enhance induction of a Stern layer at the surface being cleaned to facilitate release of a contaminant material and increase the dispersion effects allowing the contaminant to be rinsed away with the solvent or rinse water flow.
Embodiments of the present invention further provide a series of compounds (typically various salts, carbonates or the like) that are dissolved at specified rates and then injected through a device that “ionizes”, “electrolyzes”, or otherwise embarks a “charge” (oxidation/reduction potential or “ORP”) into the solution. As described above, the bonds between the contaminants and the substrates are commonly electrostatic in nature, and the ability to modify the potential of the cleaning solution plays a role in the ability to satisfy these bond charges and release the contaminants from the underlying surface(s). Thus, breaking the electrostatic bonds that hold contaminants to a surface is an important step in surface cleaning. The ability to control/adjust the oxidation/reduction potential (ORP) provides a means to adjust cleaning solutions as needed to address various cleaning applications. Embodiments of the invention directly act on the electrochemical charge balance between the solid-liquid, or solid-contaminant interface to reversibly alter the electrochemical potential and overcome the technical impediments to efficiently clean a specific surface. Embodiments of the invention directly modify the electrochemical properties of contaminants to recover fluid and solid contaminants and increase the cleaning efficiency by controlling the electrochemical charge that trapped or fixed the contaminants to a surface. The Embodiments herein adjust the electrochemical state of the carrier fluid to address variations in bonding potential that promote release of the fluid and contaminants allowing them to be rinsed away for improved cleaning efficiency.
In addition, various compounds can be added to the solutions to enhance wettability, the creation of micelles, and the chelation or sequestration of removed pollutants. Several biodegradable materials can be used in this manner. These materials may include alkyl glucosides, alcohol ethoxylates, humic/fulvic acids and or combinations of theses materials or other compounds.
Some embodiments of the present invention control the electrochemical state of the substrate by electrochemically altering a carrier fluid prior to its application onto a substrate. The electrochemically altered carrier fluid can use either a negative or reducing potential (excess of electrons) or a positive or oxidizing potential (lack of electrons), and the amount of charge can be modified to control the cleaning operation. A split cell electrolysis device can generate both solutions from the split stream exiting the electrolysis subsystem. The electrical potential of the solutions can be controlled by adjusting current density, total dissolved solids, plate size and type, membrane type, voltage, fluid residence time, or a combination of these variables. This allows a user to “tailor” the cleaning fluid potential to the target contaminent. Manipulation of potential allows for the utility to create a product that can be optimized to remove a wide range of pollutants that are attracted by varying electrostatic forces. A properly adjusted charged carrier fluid will remove pollutants and prevent their reattachment to the surface being cleaned. Various sequestering materials can also be added to assist in this process.
Embodiments of the present invention also adjust and control the pH of the carrier fluid to improve efficiency of the cleaning process. Generally, an increase of the reducing potential results in a greater pH of the carrier fluid. Conversely, the lower the reducing potential (increased oxidizing potential) used, the lower the pH of the carrier fluid. pH can be adjusted by any number of means including increasing the current to the electrolysis system to affect a corresponding lower pH from the anodic stream, mixing the electrolyzed streams, and/or injecting buffers neutralizing to correspondingly higher or lower pH values as may be advantageous for the task at hand. How to generally modify pH is known to one of skill in the art.
Embodiments of the present invention produce a contact biocide as a product of the process as described herein. To determine the disinfecting ability of a solution, ionic concentration, pH concentration, and Oxidation Reduction Potential, (ORP), are used as indicators of effectiveness. The pH range dictates which chlorine species are present in the greatest concentration. For instance in an aqueous solution with a pH of 6.0, 96.5% of the free available chlorine species are available as HOCl. Raise the pH to 8.5 and only 15% of the chlorine is available as HOCl, while nearly 85% of the chlorine is available as hypochlorite ion, −OCl−. From the pool and spa industry we know the oxidizing power of hypochlorous acid is 80 times more effective than hypochlorite, therefore the pH should be maintained below pH 6 to maximize HOCl concentration. The ORP, or redox potential, is a measurement, in millivolts, of the difference in electrical pressure, or the potential for a flow of electrons between oxidizing and reducing agents. This provides an indication of the strength of the charged fluid as an oxidizer, with a very positive ORP, or as an effective reducer indicated by a very negative ORP. Embodiments of the invention can produce a charged oxidizing fluid with high ORP to effectively utilize this mechanism. Anaerobic microorganisms, (U.S. Pat. No. 3,884,777, May 20, 1975, Cyril J. Harke and Jeffery D. Eng, Hooker Chemicals and Plastics Corporation; Electrolytic process for manufacturing chlorine dioxide, hydrogen peroxide, chlorine, alkali metal hydroxide and hydrogen), like Tetanus and Botulinum for instance, are active only at negative, or reducing ORP values from about −700 to −200 mV, while aerobic microorganisms are active only at positive, or oxidative ORP values from about +200 to +820 mV. To kill or eliminate these microorganisms, application of charged fluids which produce an oxidizing environment which disrupts and kills these pathogens is required. A charged fluid with an ORP greater than +850 mV will readily kill both anaerobic and aerobic pathogens with far less molar mass than traditional chemical methods. For example, bleach must be used in much greater mass in order to prevent the active HOCl in the system from becoming a limiting reagent in the disinfection mechanism. The truly active disinfection species which provide the electrical charge gradient necessary to affect the same kill efficacy are in smaller relative concentration due to the pH and ORP of the system. The present invention effectively utilizes this mechanism by providing a charged fluid which is completely active with little excess active molar mass. Due to the availability of HOCl and high positive or oxidizing ORP value of this fluid is an extremely effective cold, contact, biocidal disinfectant. Therefore the human and environmental exposure problems associated with the use of bleach, quaternary ammonium compound, and other chemical disinfectants can be vastly reduced representing advancement in the state-of-the-art.
The electric properties of these charged fluids decay over time and therefore for maximum efficacy these compositions are preferably utilized as they are produced. Shelf life of bottled compositions will maintain maximum efficacy for up to a few weeks. By controlling the oxidation potential of the electrolyzed solution and combining it with a “cleaning booster” to create a micelle, provides a unique controllable cleaning and sanitization method that can be dispensed conveniently to the point of use, for example dispersing with a device as described in U.S. Patent application 60/913,287 as incorporated by reference herein or similar means familiar to one skilled in the art.
Further, embodiments of the present invention control the electrochemical state of the surface without the introduction of expensive or complex synthetic chemicals thus reducing overall costs and chemical exposure liability. This allows the contaminants to be extracted and processed at a lower cost than conventional methods, significantly advancing the state-of-the-art.
Surface-fluid mechanisms operate at a different textual scale with fluid saturations related to the pore throat radius and the resulting capillarity. At a much finer spatial scale, where surface active charges begin to dominate, the accommodation of surface charge and the charge of the contiguous fluids influence imbibition at the solid-fluid interface. This interface has a width approximately several molecular dimensions where again the charge between the surface and the fluid is the ζ-potential charge boundary. The imbibition affects the properties that control release of the contaminant.
The ability to remove contaminants from a substrate occurs due to the deliberate manipulation at the surface with reversible changes in ζ-potential as an electrochemical factor for improved contaminant removal. This is an unexpected and surprising aspect of the invention described herein that significantly advances the state-of-the-art.
Using an appropriately charged fluid in conjunction with other components which will commonly be added to address specific removal requirements also significantly improve contaminant removal efficiency. Post injection of various cleaning boosters, surfactants (see for example, U.S. Pat. No. 3,390,065, Jun. 25, 1968, Hal B. H. Cooper; Process and cell for the manufacture of either sodium hypochlorite or chlorine for illustrative sufactants), sequestering agents and/or other compounds to adequately address various aspects of the mechanisms required for cleaning can be readily accomplished. The addition of cleaning boosters is utilized to address issues of capillary penetration (wettability) where contaminants may be entrapped. Various boosters may be used to decrease surface tension and create a low “angle of attack”. This allows for penetration into subsurface capillaries, and assists in the delivery of the charge from the electrochemically altered fluid to satisfy the bonding potential of the contaminant. The enhancement of wettability, creation of micelles or psuedomicelles, and the sequestration of pollutants can be invoked by the addition of various materials in the charged fluids to assist in the cleaning and sanitation process. In addition these materials may be selected to enhance the electrical properties of the charged fluid increasing cleaning efficacy. These materials may include alkyl glucosides, alcohol ethoxylates, humic/fulvic acids, or a combination of theses materials and/or other compounds.
DEFINITIONS FOR USE HEREINIn order to ensure a proper understanding of the present electrolytic contaminant removal system, the following definitions are provided to clarify the terminology as used herein. The definitions are not meant to be limiting in nature.
Bond strength—In chemistry, bond strength is measured between two atoms joined in a chemical bond. It is the degree to which each atom linked to a central atom contributes to the valence of this central atom. Bond strength is intimately linked to bond order.
Capillarity—describes the saturation distribution in a porous media with smaller pores spaces increasingly occupied by the wetting phase. All human contact surfaces have nearly invisible textures which act to “lock” a soil onto a surface.
Carrier fluid—water, brine, or other fluid substance that can be treated and introduced to alter the electrochemical state of the liquid-solid interface.
Chelation material—a material used to induce a chemical compound in which metallic and nonmetallic, usually organic, atoms are combined. These compounds are characterized by a ring structure in which a metal ion is attached to two nonmetal ions by covalent bonds.
Cleaning Booster—Compound(s) that reduce surface tension, increases wettability, work in conjunction with ORP to enhance cleaning effectiveness and/or have the ability to bind removed materials.
Contaminant—(pollutant) a contaminant (pollutant) is any potentially undesirable substance (physical, chemical, or biological) attracted to a surface.
DLVO Theory (7)—The DLVO theory is named after Derjaguin, Landau, Verwey and Overbeek who developed it in the 1940s. The theory describes the force between charged surfaces interacting through a liquid medium. It combines the effects of the van der Waals attraction and the electrostatic repulsion due to the so called double layer of counter ions. The electrostatic part of the DLVO interaction is computed in the mean field approximation. For two spheres of radius a with constant surface charge Z separated by a center-to-center distance r in a fluid of dielectric constant 6 containing a concentration of monovalent ions, the electrostatic potential takes the form of a screened-Coulomb or Yukawa repulsion,
where λB is the Bjerrum length, κ−1 is the Debye-Hückel screening length, which is given by κ2=4πβn, and β−1=κβT is the thermal energy scale at absolute temperature T, all in consistent units.
Electrolyzer—Any device that has the ability to electrolyze fluids above or below a baseline potential. The configuration of an electrolyzer apparatus may include systems using simple electrolysis with or without a membrane (e.g., ported systems or other configurations), variations in plate configurations, types or materials, or any other embodiment that is able to produce a charged fluid adequate to generate beneficial results during the cleaning/disinfecting process.
Imbibition—The displacement of one fluid by another immiscible fluid. In the oilfield imbibition is defined as the process of absorbing a wetting phase into a porous rock. Spontaneous imbibition refers to the process of absorption with no pressure driving the phase into the rock. The wettability of the rock is determined by which phase imbibes more.
Interfacial Tension—Interfacial tension is somewhat similar to surface tension in that cohesive forces are also involved. However the main forces involved in interfacial tension are adhesive forces (tension) between the liquid phase of one substance and either a solid, liquid or gas phase of another substance. The interaction occurs at the surfaces of the substances involved, that is at their interfaces. Interfacial tension also plays a important role in emulsification which is the process of preparing emulsions, which are heterogeneous systems consisting of at least one immiscible liquid intimately dispersed in another in the form of droplets.
Micelle—an electrically charged particle formed by an aggregate of ions or molecules in soaps, detergents, and other suspensions
Oxidation Reduction Potential (redox potential, or ORP)—A quantitative measure of the energy of an oxidizing or reducing system. Oxidation is equivalent to a net loss of electrons by the substance being oxidized, and reduction is equivalent to a net gain of electrons by the substance being reduced. The oxidation-reduction reaction involves a transfer of electrons. The oxidation-reduction potential may be expressed as the ability to give or receive electrons and is expressed in terms of millivolts (mV) which may be either positive (lack of electrons) or negative (excess of electrons).
Sequestration material—Sequestrants form chelate complexes with polyvalent metal ions. Chelating is the binding or complexation of a bi- or multidentate ligand. These ligands, which are often organic compounds, are called chelates, chelators, chelating agents, or sequestering agents. The ligand forms a chelate complex with the substrate. The term is reserved for complexes in which the metal ion is bound to two or more atoms of the chelating agent, although the bonds may be any combination of coordination or ionic bonds.
Surfactant—Surfactants, SURFace ACTive AgeNTs, also known as tensides, are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids. Surfactants reduce the surface tension of water by adsorbing at the liquid-gas interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid-liquid interface. Many surfactants can also assemble in the bulk solution into aggregates. Some of these aggregates are known as micelles. The concentration at which surfactants begin to form micelles is known as the critical micelle concentration or CMC. When micelles form in water, their tails form a core that can encapsulate an oil droplet, and their (ionic/polar) heads form an outer shell that maintains favorable contact with water. When surfactants assemble in oil, the aggregate is referred to as a reverse micelle. In a reverse micelle, the heads are in the core and the tails maintain favorable contact with oil. Surfactants are often classified into four primary groups; anionic, cationic, non-ionic, and zwitterionic (dual charge). Ordinary (dishwashing) detergent, for example, will promote water penetration in soil, but the effect would only last a few days (although many standard laundry detergent powders contain levels of chemicals such as sodium and boron, which can be damaging to plants, so these should not be applied to soils). Commercial soil wetting agents will continue to work for a considerable period, but they will eventually be degraded by soil micro-organisms. Some can, however, interfere with the life-cycles of some aquatic organisms, so care should be taken to prevent run-off of these products into streams, and excess product should not be washed down gutters. U.S. Pat. No. 3,390,065, Jun. 25, 1968, Hal B. H. Cooper; Process and cell for the manufacture of either sodium hypochlorite or chlorine.
Zeta potential ({tilde over (ζ)}potential), (U.S. Pat. No. 1,199,472, Sep. 26, 1916, Isaac H. Levin; Electrolytic Apparatus; U.S. Pat. No. 1,374,976, Apr. 19, 1921, Herbert I. Allen and Kent R. Fox; Electrolytic Cell; U.S. Pat. No. 3,334,035, Aug. 1, 1967, Jule N. Dews and George J. Harris, United States of America; Process for sterilization with nascent halogen; U.S. Pat. No. 3,361,663, Jan. 2, 1968, William Bruce Murray and John W. Christensen; Sanitizing System) the charge potential that develops at the interface between the counter ions developed on a solid surface and a liquid medium. This potential, which is measured in millivolts, may arise by any of several mechanisms. Included among these are the dissociation of ionogenic groups in the particle surface and the differential adsorption of solution ions into the surface region, or the insulation storage of electrical charge.
COMPOSITIONS OF THE INVENTIONFor example it can be demonstrated that providing a chemical cleaning composition will create an opposing negative charge to about −320 mV which will release materials from a surface up to about +290 mV. This charged fluid may be produced chemically by dissolving sodium hydroxide into water which is the principle utilized in traditional cleaning solutions. In effect, embodiments herein increase the ζ-potential between the surface and a contaminant material causing repulsion of the material particles from the fixed surface. If these materials are electrostatically attracted to the surface at a charge greater than 290 mV, the chemically generated cleaning composition will not prevent the materials from adhering to the surface and therefore would require a charged fluid of a potential greater than that to affect release of the material.
Embodiments of the present invention provide the needed charged fluid produced by electrolysis of an aqueous stream injected with an enhancement which embarks the oxidation reduction potential needed to remove contaminants attracted to surfaces across a wide range of positive or negative charges. Materials which adhere to a surface beyond ±1 volt may be said to be electroplated. Most naturally occurring human and food soils will not be attracted at near this potential. Therefore an electrically charged fluid, given enough time to induce a stem layer, will release most materials, including scales, from a surface. This is one basis of the effectiveness of the present invention in that these charged fluids are safe cleaning compounds because they utilize electrochemical properties and low active chemical molar mass. Unlike traditional chemical cleaning methods they do not require the high active chemical molar mass needed to achieve the charge necessary to release and disperse, or clean a material from a surface.
An embodiment the present invention comprises the production of a variety of cleaning and sanitizing solutions optimized for efficacy and economy for the task at hand. These charged compositions by nature should be utilized as they are produced, as their electrolytic properties are readily dissipated upon contact with the atmosphere or the container surfaces which they come in contact with. The present invention overcomes this limitation by demonstrating a means to deliver the compositions as they are produced conveniently to the point where they are required for the task at hand. In these embodiments, eliminating storage of the fluids of the invention can be optimized for the task at hand and delivered fresh for maximum efficacy, conveniently where and when they are needed. These compositions may be controlled in a variety of ways, including ORP, pH, ionic concentration, booster dilution rates, and many other factors.
For example, in an embodiment of the present invention, for production of an all purpose cleaner composition, the system is optimized to produce a reducing fluid with a reducing potential in a range of −100 mV to −1200 mV with the injection at a dilution rate within a range of 1:400 to 1:50 of a biodegradable booster optimized for dispersion and sequestration in a reducing environment at a pH 8 to 13 to effect greater removal of most common contaminants including greases, fats, oils, proteins, and starches.
This composition, however, would prove ineffective and wasteful for application as a glass and mirror cleaner. Testing has demonstrated that boosters added at this rate cause streaking when used on glass and mirror cleaning tasks. The present invention could be configured to provide a separate composition for crystal, glass, and mirror cleaning tasks.
For the composition above, the system would be optimized to produce a reducing fluid with a reducing potential in a range of −100 mV to −1200 mV with the injection at a dilution rate of 1:500 to 1:200 of a biodegradable booster optimized to effect removal of most common contaminants as may be found on glass and mirror surfaces. This solution would be too light for removal of contaminant mass for cleaning floors. To clean floors a greater mass of booster would be required than used for glass and mirror applications. The floor cleaner composition also would not require the booster mass required for an all purpose degreasing composition as noted above. The floor cleaning composition, for example, is optimized in the present invention to provide a reducing fluid in a range of −100 mV to −1200 mV with the injection at a dilution rate of 1:450 to 1:50 of the biodegradable booster to effect greater removal of contaminants consisting of dirt, grease, soil or other materials as may be tracked or spilled on the floor surface which may be required to be removed for effective cleaning of these surfaces. Once contaminants are removed from a surface it may be necessary to further sanitize the surface to remove potential pathogens left behind during the cleaning task. The present invention can be optimized to produce a powerful contact biocide. For example, another embodiment of the present invention for production of a disinfectant/sanitizer composition the system would be optimized to produce an oxidizing fluid using sodium chloride as an influent enhancement to produce a charged fluid of hypochlorous acid with a potential in a range of +100 to +1200 mV with the injection at a dilution rate of 1:500 to 1:200 of a biodegradable booster optimized for wettability and sequestration in an oxidizing environment at a pH of 2 to 6 to effect greater efficacy for the remediation of biological pathogens. This great reduction in the concentration of the booster while maintaining efficacy for the task at hand and the ability of the present invention to provide compositions of both oxidizing and reducing fluids as needed represents a reduction in the cost structure of providing materials optimized for a wide variety of cleaning and sanitizing tasks thus advancing the state of the art. Table 1 provides several tailored compositions in accordance with the present invention.
An embodiment of the present invention could be utilized as illustrated in
As illustrated in
The utilization of the present invention as illustrated in
Cathode(−):Na++e−→NaEored=−2.71 V
2H2O+2e−→H2+2 OH−Eored=−0.83 V
Because it is much easier to reduce water than Na+ ions, the only product formed at the cathode is hydrogen gas. Cathode (−): 2H2O(l)+2e−→H2(g)+2OH− (aq)
There are also two substances that can be oxidized at the anode: Cl− ions and water molecules.
Anode(+):2 Cl−→Cl2+2e−Eoox=−1.36 V
2H2O→O2+4H++4e−Eoox=−1.23 V
The standard-state potentials for these half-reactions are so close to each other that we might expect to see a mixture of Cl2 and O2 gas collect at the anode. In practice, the only product of this reaction is Cl2. Anode (+): 2 Cl−→Cl2+2 e−
At first glance, it would seem easier to oxidize water (Eoox=−1.23 volts) than Cl− ions (Eoox=−1.36 volts). It is worth noting, however, that the cell is never allowed to reach standard-state conditions. The solution is typically 25% NaCl by mass, which significantly decreases the potential required to oxidize the Cl− ion. The pH of the cell is also kept very high, which decreases the oxidation potential for water. The deciding factor is a phenomenon known as overvoltage, which is the extra voltage that must be applied to a reaction to get it to occur at the rate at which it would occur in an ideal system, (U.S. Pat. No. 3,793,163, Feb. 19, 1974; Process using electrolyte additions for membrane cell operation).
Under ideal conditions, a potential of 1.23 volts is large enough to oxidize water to O2 gas. Under real conditions, however, it can take a much larger voltage to initiate this reaction. (The overvoltage for the oxidation of water can be as large as 1 volt.) By carefully choosing the electrode to maximize the overvoltage for the oxidation of water and then carefully controlling the potential at which the cell operates, we can ensure that only chlorine is produced in this reaction.
In summary, electrolysis of aqueous solutions of sodium chloride doesn't give the same products as electrolysis of molten sodium chloride [see,
Electrolysis of aqueous NaCl solutions gives two charged fluid streams. One is a mixture of hydrogen which is vented as a gas and chlorine available as hypochlorous acid with a very positive ORP, the concentration of which may further be controlled by the pH of the system (407). The present invention can adjust any combination of pH and ionic concentration thus making a variety of oxidizers (407) such as hypochlorous acid available for effective contact sanitization. The other stream is an aqueous sodium hydroxide solution (408) with a very negative ORP.
Electrolysis of an aqueous NaCl solution has two other advantages familiar to anyone skilled in the art. It produces H2 gas at the cathode, which can be collected and sold. It also produces NaOH, which can be utilized for cleaning a wide variety of surfaces.
2 NaCl(aq)+2H2O(l)→Na+(aq)+2OH−(aq)+H2(g)+Cl2(g).
Both ionized materials will also have a significant “shift” in their respective redox potential from the initial state of the carrier fluid as the carrier fluid is adjusted to a different ionic state. The alkaline side will have a dramatic increase in excess electrons and become a powerful reducing agent. The opposite is true for the acidic side, which is deficient in electrons and is thus a powerful oxidizer. These shifts in redox potential can be well in excess of + or −1000 mV as measured by ORP. This limit can be as high as where the carrier fluid completely disassociates and will not carry any additional charge, or is no longer useful to the process. Alternatively, any measurable change in redox may be sufficient to produce desirable results. This measurement can be made by an ORP meter or more sophisticated data logging can be achieved by using a continuous flow through design, such as with inline pH/Eh/ORP analyzers or any other means familiar to one skilled in the art. Combinations of changing Eh, pH, ORP, and the addition of select ions to modify the ionic state of the carrier fluid prior to application on contaminated substrates allows for controlled decontamination.
The change in redox potential dissipates by various physical responses on the substrates. As illustrated in
In the past, electro osmosis was the most popular method to determine the ζ-potential. Marian Smoluchowski was the first to properly derive an equation to calculate the ζ-potential from electrokinetic mobility. Smoluchowski equation, (U.S. Pat. No. 1,374,976, Apr. 19, 1921, Herbert I. Allen and Kent R. Fox; Electrolytic Cell):
where μ is the electrophoretic mobility, ∈ is the electric permittivity of the liquid and η is the viscosity. The electrostatic driving force is opposed by the frictional force and the other effects are neglected. Only when the ζ-potential is not too high and for large colloidal particles and high ionic strengths this equation gives good results. For the values of ζ-potential with a practical meaning (ζ<120 mV) the error is negligible when κ·α>100 where α is the particle radius and the Debye parameter kappa, κ, is defined as (U.S. Pat. No. 1,374,976, Apr. 19, 1921, Herbert I. Allen and Kent R. Fox; Electrolytic Cell):
where −F is Faraday's constant, ci is the concentration of the i-th ion (in mol/m3), −zi is the valence of this ion, R is the gas constant, and T is the absolute temperature. The reciprocal κ, is often termed as the thickness of the electric double layer so the Smoluchowski equation applies for thin double layers (as compared with the particle radius). Unfortunately, for many colloids of practical importance κ·α>100 and Smoluchowski equation may lead to serious errors.
The ζ-potential of a particle may also be calculated using Henry's equation if the electrophoretic mobility, Ue, of the sample is known:
where Ue is the electrophoretic mobility, ∈ is the dielectric constant of the sample, ζ is the ζ-potential, f(κ·α) is Henry's Function (most often used are the Huckel and Smoluchowski approximations of 1 and 1.5, respectively), and η is the viscosity of the solvent.
The electrochemical potential for a dilute solution of binary electrolytes is presented as,
where v and u are the anion and cation mobility, respectively, Z is the valance of the ions, and F is in faradays. The constant R is the real gas constant and T is absolute temperature. R1 and R2 are the resistivity of the two fluids. For sodium chloride at 25° C. this reduces to
in millivolts.
Electro-osmosis transport of a fluid through a porous plate occurs when a potential difference is maintained between two electrodes. The diffuse charged layers at the solid-liquid interface can be idealized as two parallel plates at a distance, d, apart. The charge potential per unit area, e, on a plate, the dielectric constant of the media, D, and ∈0 which is 8.85(10−12) coulomb2/N−m2, so that ζ-potential in volts is,
When an electrical potential is applied in a porous media, a gradient E exists within the liquid-filled pore space. As electrical forces dissipate the charge, the wetting fluid at the solid-liquid interface is physically dragged by flow potential along the charged interface, altering the wettability characteristics at the solid-liquid interface. This potential can either increase or decrease the preferred wettability at the interface, depending on the magnitude and direction of the change in charge. The total displacement force is given by the integral,
FE=∫eEAdA.
where K is the aspect ratio of a cell (width/thickness), b is the half thickness of a cell, and hs is the static layer or distance from the center of the cell.
The outer region where a balance of electrostatic forces and random thermal motion determines the ion distribution is known as the diffuse layer. The potential at this boundary (surface of hydrodynamic shear) is known as the ζ-potential. The ζ-potential acts on the solid-liquid interface at the surface of hydrodynamic shear. If electrical forces displace or change the charge, liquids can either be released or entrapped from the solid-liquid interface. If two immiscible fluids are present, a change in charge will result in one phase becoming preferentially more attracted (increased wettability) at the expense of the second fluid. Altering the ζ-potential at the contaminant substrate interface can thus release or entrap a contaminant. By introducing an ionized carrier fluid with sufficient charge at the solid-liquid interface, the charge on the carrier fluid disrupts the ζ-potential, releasing the contaminant from the surface.
Particles dispersed in a solution are electrically charged due to their ionic characteristics and dipolar attributes. The dispersed particles are surrounded by oppositely charged ions and an outer diffuse layer, with the whole area being electrically neutral (the difference being the ζ-potential). As the potential between the particles and the fluid decreases, the particles have a tendency to aggregate.
Van der Waals forces can act at the pore scale as a contaminate capture mechanism. The solid-liquid interactions occur at smaller and smaller scales until they approach the region where van der Waals attractive forces are a contaminant capture and storage mechanism. The introduction of excess electrons (redox shift to more negative charge) will increase the water wettability, releasing the contaminant from a surface, as more of the internal pore structure becomes water wet.
In embodiments herein, the change in charge can be reversibly controlled by the introduction of an oppositely charged carrier fluid, thus directly changing the surface wettability state and the ζ-potential. The charge can be reversed by introducing an oppositely charged carrier fluid into the system. Summarizing, the charge can be reversed by the introduction of an oppositely charged fluid having either an excess or deficit of electrons. Since the ionization process produces both types of fluid, either is available to customize the decontamination process to achieve maximum efficiency.
The theoretical and experimental verification of solid-liquid interfaces demonstrates that excess electrons, whether introduced externally by chemicals or by on site generation, changes the ζ-potential as excess electrons are dissipated, releasing contaminants from the complex pore geometry of the surface by making the system more water wet.
The present invention in a preferred embodiment utilizes an electrolysis system (406) to produce the charged fluids which can be used to modify the ζ-potential which describes the forces which cause a disparate material to become attracted to or repelled from a surface. As illustrated in
The opposite is also true. Where a carrier fluid having a lack of electrons (oxidizing condition) is introduced, the wettability will shift to an increasing oil-wet state. Reversibly controlling the wettability of a surface allows for improved control of extraction and or deposition processes.
Further, the present invention illustrates a convenient means of utilization (412) by providing a user interface (413) which initiates pumps (411) to provide the oxidizing fluid (407) or reducing fluid (408) to the point of use. To further enhance and optimize the efficacy of the reducing fluid (408) a cleaning booster (410) can be embarked to the reducing fluid flow to enhance dispersion, sequestration, and wettability of the surface being cleaned and the contaminants being removed from that surface. While the reducing fluid (408) has been demonstrated to be effective removing contaminants from surfaces some cleaning booster (410) may be embarked to the reducing fluid (408) flow to remove heavy soils or contaminants or residues which may have an enhanced attraction to a surface due for example to heat from cooking. These difficult materials can be manipulated by the present invention utilizing cleaning boosters (410) which by controlled function enhance the wettability, dispersion, and or further sequestration promoting the cleaning of the surface.
As illustrated in
A great deal of research has gone into analysis of the significance of hysteresis. It has been used to help characterize surface heterogeneity, roughness and mobility, (U.S. Pat. No. 3,640,804, Feb. 8, 1972, Chemech Engineering Ltd.; Method for conducting electrolyte to, from, and through an electrolytic cell). For surfaces which are not homogeneous there will exist domains on the surface which present barriers to the motion of the contact line. For the case of chemical heterogeneity these domains represent areas with different contact angles than the surrounding surface. For example, as illustrated in
γlv cos θ=γsv−γsl
where γlv, γsv and γsl refer to the interfacial energies of the liquid/vapor, solid/vapor, and solid/liquid interfaces. The theoretical description of contact arises from the consideration of a thermodynamic equilibrium between the three phases: the liquid phase of the droplet (L), the solid phase of the substrate (S), and the gas/vapor phase of the ambient (V) (which will be a mixture of ambient atmosphere and an equilibrium concentration of the liquid vapor). The V phase could also be another (immiscible) liquid phase. At equilibrium, the chemical potential in the three phases should be equal. It is convenient to frame the discussion in terms of the interfacial energies. The Young equation can be written as an equation that must be satisfied in equilibrium:
0=γsv−γsl−γ cos θ
where θ is the experimental contact angle. Thus the contact angle is used to determine an interfacial energy (if other interfacial energies are known). This equation can be rewritten as the Young-Dupré equation:
γ(1+cos θ)=ΔWslv
where ΔWslv is the adhesion energy per unit area of the solid and liquid surfaces when in the vapor medium.
The preceding discussion demonstrates that in order to manipulate or change the wettability state, a change of the ζ-potential will directly entrap or release a particle electrostatically fixed to the solid surface. A particle can consist of either a solid or a liquid that is fixed to a surface. The introduction of a charged carrier fluid can reverse the electrostatic state and release the particle. Most chemical based systems can effect a change of charge on the order of 50 to 80 mV and by doing so result in the release of some contaminate. The process outlined herein provides a charged fluid that can result in a change in charge on the order of ±100 mV or more, ±200 mV or more, ±300 mV or more, ±400 mV or more, ±500 mV or more, ±600 mV or more, ±700 mV or more, ±800 mV or more, ±900 mV or more, and the like, in preferred embodiments the charged fluid has a charge change on the order of ±800 mV or more (e.g., ±825 mV, ±850 mV, ±875 mV, ±900 mV, ±925 mV, etc.). Thus, embodiments of the present invention provide methods and systems that can remove materials that previously would have required expensive and exotic technologies using no or greatly reduced chemical inputs. We demonstrate that much greater charge potentials can be achieved directly with the carrier fluid, allowing for improved removal and sequestration.
In another embodiment, the charge required to remove or substantially remove a target contaminate is determined (or at least considered). A fluid carrier is charged to the appropriate concentration of cleaning boosters for the target contaminate, including any required pH modification and application of the fluid to the target contaminate for contaminate removal.
Embodiments of the present invention for surface cleaning includes a means for providing a carrier fluid; a means for providing a pair of electrodes interposed by a permeable membrane or other configuration to create a first channel and a second channel; a means for flowing the carrier fluid through the first and second channel; a means for applying an electrical potential to the pair of electrodes to produce a first electrolyzed carrier fluid in the first channel and a second electrolyzed carrier fluid in the second channel; a means for post-injecting cleaning boosters into the electrolyzed carrier fluids, and a means to apply the enhanced carrier fluid to various surfaces in order to release contaminants.
Manipulation of potential allows for the utility to create a product that can be tailored to remove a wide range of pollutants that are attracted by varying electrostatic forces. A properly adjusted charged carrier fluid will remove contaminants and prevent their reattachment to the surface being cleaned.
The enhancement of wettability, creation of micelles and the sequestration of pollutants can be invoked by the addition of various materials to the charged fluids to assist in the cleaning and sanitation process. These materials may include alkyl glucosides, alcohol ethoxylates, humic/fulvic acids and or combinations of theses materials or other compounds.
ExampleHaving generally described the invention, the same will be more readily understood by reference to the following example, which is provided by way of illustration and is not intended as limiting.
The purpose of these experiments was to verify the efficacy of the charged oxidizing fluids produced by an embodiment of the present invention as an effective sanitizer on food contact surfaces. These experiments were limited and performed as a indication of the effectiveness of the sanitizer for mitigation of biological contamination on food preparation surfaces. In this example, testing was conducted on 59 samples from an active retail facility. This included samples from the bakery, deli, produce, meat, and the retail sales floor (i.e., shopping cart) areas.
An electrolytic cell apparatus (see U.S. Patent Application No. 60/913,287 incorporated herein by reference for all purposes) was used to generate a charged fluid with a highly oxidizing potential. This solution was then combined with various wetting, sequestering, and micelle forming agents (described above) as needed for sanitizing operations. A dispensing and dilution mechanism was then utilized to blend the solutions to the proper ratios optimized for particular applications prior to use. The oxidizing test solution consists of acidic electrolyzed oxidizing water and is verified for efficacy by testing the quality of the oxidizer as a sanitization agent. By checking pH, ORP, and chlorine concentration values, suitability of the test solution is established. To maintain maximum effectiveness of the oxidizer the pH should be between 2.8 and 4. ORP values over 650 mV indicate the oxidizer is an effective biocidal disinfectant. Regulation 21 CFR 178.1010 requires that the hypochlorous acid concentration of the solution must be greater than 100 ppm but less than 200 ppm for use on food processing equipment, utensils, and food contact surfaces in public eating places.
The test solution utilized to collect these data was measured at +1175 ORP using a Hanna HI98201 ORP meter calibrated with 200 mV reference solution measuring 202 mV. The pH was measured at 2.8 using pHydrion MicroFine 1.3 to 4.4 pH paper. Active chlorine concentration was measured at 150 ppm using pHydrion Micro Chlorine test paper.
A Hygiena systemSURE II ATP Bioluminescence hygiene monitoring system, S/N: 000998, was used to evaluate food contact surfaces within the Bakery, Deli, Produce, and Meat department areas. A shopping cart was also tested as a sample of a critical control point with very high customer contact. The systemSURE II™ ATP-bioluminescence hygiene monitoring system, in conjunction with the Ultasnap™ ATP sampling device, measures adenosine triphosphate, the universal energy molecule found in all animal, plant, bacterial, yeast, and mold cells. Product residue, particularly food residue, contains large amounts of ATP. Microbial contamination also contains ATP, but in smaller amounts. When ATP is brought into contact with the luciferase/luciferin reagent in the Ultrasnap™ sampling device, light is emitted in direct proportion to the amount of ATP present. The Luminometer measures the amount of light generated and calculates an indication of contamination as Relative Light Units, or RLU. One RLU is basically equivalent to one femtomole of ATP. All sources of ATP should be removed after effective cleaning and sanitization. Effective sanitization is indicated by low RLU values.
Samples were collected with Hygiena Ultrasnap ATP swabs, lot #35306, by swabbing an area that is about 4 square inches (10 cm2) or in the case of a hard-to-clean area, as much of the surface as possible. Do not let the swab come into contact with anything other than the test area to avoid cross-contamination. Pressure was applied to the swab to pick up surface residue and to penetrate any biofilms that was present. After collecting the sample, the swab was placed back in the swab tube. The swab was read in the SystemSURE II™ within 10-60 seconds. Swabbing was done after cleaning a surface, but prior to the application of a sanitizer. This removed any residue detected by the SystemSURE II™ with proper cleaning, before applying sanitizer. In some instances swabbing was done after a sanitizer had been applied, but it is recommended you wait until the surface has dried. For the purposes of this test, the efficacy of the sanitizer used on surfaces that have already been cleaned was studied. Therefore all sanitized surfaces were dried prior to sample collection. Samples were taken from each surface “as found” for a control reference using current sanitization compounds and procedures. Test areas of each surface were then treated with a charged oxidizing sanitizer or first cleaned with a charged reducing cleaner where appropriate. The relative effectiveness of the charged oxidizing sanitizer will be indicated by comparing data collected using current sanitization compounds and procedures as a reference with data from samples taken after using the oxidizing sanitizer.
It is readings less than 10 RLU which indicate that a surface is considered clean. Readings that range from 11 to 29 RLU indicate a warning that the surface may not have been adequately cleaned. If the reading is greater than 30 RLU, the surface is considered dirty. These threshold settings have been determined based on plate count and ATP correlations studies and results from daily samples in food preparation facilities. Hygiena recommends that a facility determine its own RLU thresholds according to the hygienic standards of the facility, however 10, 11-29, and 30 can be used as rough indications.
Alternatively, for the purposes of this evaluation study, the thresholds of the systemSURE II™ were set to 100 RLU as low limit, and 200 RLU as the high limit. Data readings from 0 to 100 RLU would be considered passing, 101 to 200 would be a caution, and ≧200 are failures.
The purpose of this example is to determine the effectiveness of the charged oxidizing fluid as produced by the present Embodiments of the present invention as an effective contact disinfectant relative to samples collected from surfaces cleaned and sanitized by approved methods “as found”. Therefore, pass and, fail readings were not considered for analysis of the collected data.
Data was uploaded from the Luminometer into dataSURE II™ data analysis software and used to determine efficacy of the product to sanitize surfaces by comparison with samples collected from those same surfaces “as found” previously cleaned using current compounds and procedures. The charged oxidizing fluid would be considered effective at reducing biological contamination as indicated by a reduction in RLU values from control sample values on surfaces, “as found”, sanitized by current procedures. The data results collected prove the charged oxidizing fluid is very effective at reducing biological contamination on all tested surfaces as indicated by reduced RLU values. The charged oxidizing fluid dramatically reduced, and in some cases eliminated RLU counts on every surface tested. The charged oxidizing fluid as produced by the embodiment of the present invention is a completely organic and biodegradable product; it is safe for use around food, food processing, and food service areas. The charged oxidizing fluid is easy to use and leaves no residue, making it ideal for use throughout the day to ensure maximum possible store hygiene and public safety.
The results of this testing are seen in Table 2 and a graphic comparison of relative sanitation effectiveness data are illustrated in Table 3.
Additionally cleaning of various surfaces was conducted to verify the efficacy of the charged reducing fluid enhanced with a cleaning booster to remove oil, grease, and other pollutants. Table 4 represents a summary of cleaning operations on various surfaces utilizing an enhanced charged reducing fluid as produced by the present Embodiments of the invention. This approach utilizes the generation of a reducing charged fluid that is then combined with various wetting, sequestering and dispersing agents (described above) as needed for each cleaning operation. A dispensing and dilution mechanism was then utilized to blend the solutions to the proper ratios prior to use and deliver these compounds conveniently to the point of use. The major areas within the store were identified as follows: Bakery, Deli, Produce, Produce Prep, Meat, Main Sales Floor, Dairy and Juice cases, Auto, and the Office, Storage, and Utility area in the back of the store. Each area was analyzed for required cleaning tasks and overall time or difficulty of completing those tasks. Results are then detailed after performing the cleaning tasks with a bottled test dilution of the charged fluid produced by an embodiment of the present invention. The charged reducing cleaner was compared side by side with current cleaners, where possible, and evaluated for effectiveness and any potential benefits.
The test dilution utilized to collect these data was a cleaner consisting of a charged reducing fluid measured at −837 ORP using a Hanna HI98201 ORP meter calibrated with 200 mV reference solution measuring 202 mV. The pH was measured at 11.8 using AZY pH 10.0 to 14.0 test paper. A proprietary cleaning booster containing surfactants, a wetting agent, and chelators was diluted into the charged reducing fluid at a ratio of 1 part booster to 50 parts charged reducing fluid. The cleaning booster is optimized to work synergistically with the charged reducing fluid while demonstrating minimal environmental fate as an element of wastewater effluent.
The results in Table 4 provide a semi-quantitative description of the cleaning effectiveness using the solutions produced by present embodiments of the present invention for each task described as they are to be completed by existing procedures.
Embodiments of the present invention that produce both the charged reducing fluid and charged oxidizing fluid will eliminate the need for the variety of cleaning products currently used. This will result in substantially reduced costs associated with the on-going procurement, transport and storage of these chemical cleaners. The charged reducing fluid in conjunction with the cleaning booster proved to be a superior cleaner is all areas within the scope of this study. The store personnel who participated in assisting the evaluation team during this study continually commented on their complete satisfaction with the charged reducing fluid cleaning compositions. In fact, they frequently indicated how impressed they were with how well it out-performed the products they currently use. Further, the charged reducing fluid cleaning compositions are substantially safer than the existing products. For example, the floor cleaner concentrate being used had an extremely high (3) HMIS health hazard level. Elimination of this threat to personnel and the public is paramount.
Embodiments of the present invention herein describe novel systems and methods for cleaning any surface. Further, it is evident that those skilled in the art may now make numerous uses and modifications of the specific embodiment described, without departing from the inventive concepts. For example, the carrier fluid or additives that are described can be any type of fluid useable for a desired application such as described herein. It is also evident that the process steps recited may in some instances be performed in a different order, or equivalent structures and processes may be substituted for the various structures and processes described. The structures and processes may be combined with a wide variety of other structures and processes.
The specification contains numerous citations to patents, patent applications, and publications, each of which is hereby incorporated by reference for all purposes.
Claims
1. A cleaning composition comprising an electrochemically altered carrier fluid wherein the carrier fluid has an electric charge of from about −100 mV to about −1200 mV.
2. The cleaning composition of claim 1 further comprising one or more biodegradable booster compounds.
3. The cleaning compounds of claim 2 wherein the booster is diluted from about 1:500 to 1:10, booster:carrier.
4. The cleaning composition of claim 3 having a pH of from about 8 to about 13.
5. The cleaning composition of claim 3 wherein the booster compound is selected from the group consisting of: alkyl glucosides, alcohol ethoxylates, humic/fulvic acids and mixtures thereof.
6. A cleaning composition comprising an electrochemically altered carrier fluid wherein the carrier fluid has an electric charge of from about +100 mV to about +1200 mV.
7. The cleaning composition of claim 6 further comprising one or more biodegradable booster compounds.
8. The cleaning compounds of claim 7 wherein the booster is diluted from about 1:500 to 1:200, booster:carrier.
9. The cleaning composition of claim 8 having a pH of from about 2 to about 6.
10. The cleaning composition of claim 8 wherein the booster compound is selected from the group consisting of: alkyl glucosides, alcohol ethoxylates, humic/fulvic acids and mixtures thereof.
11. A method for cleaning a surface comprising:
- providing an electrochemically altered carrier fluid, wherein the carrier fluid has a charge tailored to a target cleaning use; application of the carrier fluid to the surface; and removing the carrier fluid from the surface after an adequate amount of time has elapsed to remove contaminates from the surface.
12. The method of claim 11 further comprising:
- adding one or more booster compounds to the carrier fluid having a predetermined dilution.
13. The method of claim 11 wherein the carrier fluid and booster compound have a pH altered to optimize contaminate removal from the surface.
Type: Application
Filed: Dec 8, 2008
Publication Date: Mar 3, 2011
Applicant: WOODY AMERICA LLC (Denver, CO)
Inventors: Steve Pettee (Fairplay, CO), Mike Peters (Bailey, CO), Dave Faulder (Denver, CO)
Application Number: 12/746,160
International Classification: C25F 1/00 (20060101);
