Abstract: An electrochemical cell including a first chamber having an anode, a second chamber having a cathode, at least one ionic connection between the first chamber and the second chamber, such that liquid electrolyte from the first chamber is prevented from mixing with liquid electrolyte in the second chamber is provided. The first chamber and the second chamber can be arranged in parallel and positioned remotely from each other. An electrochemical system including the electrochemical cell, and first and second sources of saline aqueous solutions is also provided. Water treatment systems are also provided. A method of operating an electrochemical cell including introducing first and second saline aqueous solutions into first and second chambers of the electrochemical cell, and applying a current across the anode and the cathode to generate first and second products, respectively is also provided. A method of facilitating operation of an electrochemical cell is also provided.

Abstract: Systems and methods for electrochemically producing chemical products are provided. In certain cases, the systems and methods described herein are capable of producing chemical products such as hydrogen peroxide in solutions with relatively low concentrations of electrolyte or other dissolved species at high efficiencies and/or low energetic cost. In some cases, redox mediators are used to spatially decouple direct electrochemical processes from the production of the chemical product.

Abstract: Systems and methods for electrochemically producing chemical products are provided. In certain cases, the systems and methods described herein are capable of producing chemical products such as hydrogen peroxide in solutions with relatively low concentrations of electrolyte or other dissolved species at high efficiencies and/or low energetic cost. In some cases, redox mediators are used to temporally decouple direct electrochemical processes from the production of the chemical product.

Abstract: Various embodiments may include an electrolyzer for electrochemical utilization of carbon dioxide comprising: electrolysis cell defining an anode space and a cathode space; an anode in the anode space; a cathode in the cathode space; a first cation-permeable membrane disposed between the anode space and the cathode space; and a second anion-selective membrane disposed between the first cation-permeable membrane and the cathode. The anode directly adjoins the first cation-permeable membrane. The second anion-selective membrane directly adjoins the first cation-permeable membrane and the second anion-selective membrane directly adjoins the cathode.

Abstract: A method to reduce the viscosity of viscosified treatment fluids is disclosed herein. The method includes a water soluble polymer as viscosifying agent, preferably a synthetic water soluble polymer, optionally a crosslinker for the water soluble polymer, a breaker system containing an organic peroxide, mixing the viscosified treatment fluid and the breaker composition and allowing the viscosified treatment fluid and the breaker composition to interact whereby the viscosity of the viscosified treatment is reduced. The application of the process in the production of oil and gas is also discussed.

Abstract: A method to reduce the viscosity of viscosified treatment fluids is disclosed herein. The method includes a water soluble polymer, a breaker system containing at least one aliphatic azo-compound, mixing the viscosified treatment fluid and the breaker composition and allowing the viscosified treatment fluid and the breaker composition to interact whereby the viscosity of the viscosified treatment is reduced. The application of the process in the production of oil and gas and to the treatment fluids is also discussed.

Abstract: In some embodiments, a method may include reducing the microbial load in contaminated water of water recycle loops. These water recycling loops may include pulp and paper mills, cooling towers and water loops, evaporation ponds, feedstock processing systems and/or non-potable water systems. The methods may include providing a peracetate oxidant solution. The peracetate solution may include peracetate anions and a peracid. In some embodiments, the peracetate solution may include a pH from about pH 10 to about pH 12. In some embodiments, the peracetate solution has a molar ratio of peracetate anions to peracid ranging from about 60:1 to about 6000:1. In some embodiments, the peracetate solution has a molar ratio of peracetate to hydrogen peroxide of greater than about 16:1. The peracetate solution may provide bleaching, sanitizing and/or disinfection of contaminated water and surfaces. The peracetate oxidant solution may provide enhanced separation of microbes from contaminated water.

Abstract: This invention relates to a process and reactor for the electrochemical production of hydrogen peroxide. The process comprises producing protons at an anode, transporting produced protons through a cation exchange membrane into catholyte, producing peroxide anions in a cathode membrane assembly comprising a gas diffusion electrode and an anion exchange membrane adjoined to said gas diffusion electrode and in contact with said catholyte, which produced peroxide anions migrate at least in part into said catholyte, and combining protons and peroxide anions in said catholyte to form hydrogen peroxide.

Abstract: An efficient perovskite solar cells can be synthesized from used car batteries by using both the anodes and cathodes of car batteries as material sources for the synthesis of lead iodide perovskite materials.

Abstract: The electrochemical method of producing hydrogen peroxide using a titanium oxide nanotube catalyst is an electrochemical process for producing hydrogen peroxide using a cathode formed as a nanostructured titania (TiO2) electrode surface treated with nitrogen. An anode and the cathode are immersed in an alkaline solution saturated with oxygen in an electrolytic cell. An electrical potential is established across the cathode and the anode to initiate electrochemical reduction of the oxygen in the alkaline solution to produce hydrogen peroxide dissolved in the alkaline solution. The hydrogen peroxide dissolved in the alkaline solution is then collected from the cell.

Abstract: Disclosed embodiments relate to an ocean-going vessel that includes an airborne wind turbine to generate power. The generated power can be used for an electrodialysis system that extracts carbon dioxide (CO2) from seawater and/or for an electrolysis system that produces hydrogen (H2), both of which are disposed on the ocean-going vessel. The ocean-going vessel further includes a refinery system that may use a mixture of the H2 and CO2 gases that are to produce a fuel or chemical. In an example embodiment, the mixture of the H2 and CO2 gases may be processed to produce a synthetic fuel, which in turn may be processed to produce ethanol.

Abstract: The invention relates to a process for electrolysis comprising a cathode and an anode comprising a catalyst, both the cathode and anode at least partly immersed in an electrolyte, the process characterised in that the electrolyte at least partly inhibits further oxidation of a product formed at the anode. Typically the catalyst comprises one or more metal-(Group VIb) semiconductors, and one or more metal-(GroupVIb))-phosphorous species.

Abstract: The invention relates to a method for removing oxygen from a water containing reaction medium. A pair of electrodes (cathode and anode), are added to the medium, with a surfactant attached to the surface of at least one of the cathode and anode. The medium is kept at an acidic pH, and an electrical current is applied. Oxygen is drawn to the electrodes, displacing surfactant, and reacts with H+ ions and H2O molecules to form H2O2, which can then be removed.

Abstract: The electrochemical reactors disclosed herein provide novel oxidation and reduction chemistries and employ increased mass transport rates of materials to and from the surfaces of electrodes therein.

Abstract: Systems and methods for generating reactive oxygen species formulations useful in various oxidation applications. Exemplary formulations include singlet oxygen or superoxide and can also contain hydroxyl radicals or hydroperoxy radicals, among others. Formulations can contain other reactive species, including other radicals. Exemplary formulations containing peracids are activated to generate singlet oxygen. Exemplary formulations include those containing a mixture of superoxide and hydrogen peroxide. Exemplary formulations include those in which one or more components of the formulation are generated electrochemically. Formulations of the invention containing reactive oxygen species can be further activated to generate reactive oxygen species using activation chosen from a Fenton or Fenton-like catalyst, ultrasound, ultraviolet radiation or thermal activation.

Abstract: Corrosion-inhibited hypochlorite compositions and methods of use are disclosed. Corrosion inhibitors including sugar acids and calcium compounds, polyacrylate and calcium compounds, and/or zinc and calcium compounds are used with hypochlorite sources to enhance the longevity and performance of electrochemical cells as well as reducing corrosion of metal in contact with the generated hypochlorite sources. The methods for generation employ a variety of electrochemical cells, beneficially including use of portable electrochemical cell system for production of corrosion-inhibited hypochlorite cleaning solutions.

Abstract: An electrolytic cell for the production of hydrogen peroxide with faradic efficiency and a method for the production of highly pure hydrogen peroxide with high faradic efficiency are disclosed. The cell is provided with a separator of high hydraulic permeability and is equipped with an oxygen-fed gas-diffusion cathode and with an anode activated with a catalyst for oxygen evolution. The high faradic efficiency of hydrogen peroxide generation is allowed by the dilution of product hydrogen peroxide by the anolyte crossing the permeable separator, and by keeping the operating temperature at values below 50° C.

Abstract: Corrosion inhibitor compositions and methods of use are disclosed. Corrosion inhibitors are selected from polyacrylate and calcium corrosion inhibitors, zinc and calcium corrosion inhibitors and/or sugar acids and calcium corrosion inhibitors combined with hypochlorite sources provide use solutions for effective corrosion inhibition for metal surfaces.

Abstract: The invention provides a method for bleaching kitchenware in a dishwasher, comprising the step of the in situ activation of a bleach activator by means of a reactive oxygen species, where the reactive oxygen species is generated in situ in the dishwasher by electrolysis of an aqueous solution.

Abstract: Provided are various methods, systems and reactors for producing peroxycarboxylic acid compositions, such as non-equilibrium compositions of peracetic acid, for example. The methods and systems relate to electrolytic generation of hydrogen peroxide or peroxide ions in a reactor, wherein the generated materials are reacted with an acetyl donor to form peracetic acid. In an embodiment, a source of alkali metal ions is provided to an anode chamber such that the ratio of concentrations of the alkali metal ions to protons in the anode chamber of a reactor is greater than 1.

Abstract: Provided is a sterilization method and apparatus for medical instruments. In the method, a solution containing chlorine and having a temperature of about 60° C. or more is prepared. An electrode is disposed in a container containing the solution and the medical instrument is immersed in the solution such that the medical instrument is disposed over the electrode. The solution is electrolyzed by applying a current to the electrode to generate sterilizing components of free chlorine comprising hypochlorous acid, hydrogen peroxide (H2O2), OH radical, and ozone (O3) and sterilize the medical instrument by the components which move up in the opposite direction of gravity from the electrode.

Abstract: The present invention provides a manufacturing method of normal saline solution and cleansing apparatus for contact lens, more particularly, a cleansing apparatus for contact lens comprising: a lens receiver for accommodating lenses, at least one electrode unit including a negative electrode and a positive electrode which set apart from the negative electrode each other, a power supply for supplying electric current to the negative electrode and the positive electrode, thereby effectively disinfecting and sterilizing viruses and bacteria and to remove foreign substances within the short time and protein on contact lenses in the lens receiver by oxidants generated by electrolysis in the electrode unit.

Abstract: A process for producing hydrogen peroxide comprising the steps of providing a bioelectrochemical system having an anode and a cathode, feeding a feed solution containing organic or inorganic (or both) material to the anode, oxidising the organic or inorganic material at the anode, providing an aqueous stream to the cathode of the bioelectrochemical system, reducing oxygen to hydrogen peroxide at the cathode, and recovering a hydrogen peroxide containing stream from the cathode.

Abstract: The invention relates to a process for the production of alkali metal chlorate comprising: providing an electrochemical cell comprising an anode and a cathode in separate anode and cathode compartments; contacting the cathode with an electrolyte comprising at least one organic mediator and one or more organic or mineral acids; reacting the organic mediator at the cathode to form at least one reduced form of the mediator; reacting the at least one reduced form of the mediator with oxygen to form hydrogen peroxide; contacting the anode with an anolyte comprising alkali metal chloride; reacting chloride at the anode to form chlorine that is hydrolyzed; and, reacting the hydrolyzed chlorine to form chlorate.

Abstract: Methods, apparatus, and applications for the on-site production of hydrogen peroxide are described. An embodiment of the apparatus comprises at least one anolyte chamber coupled to at least one anode, at least one catholyte chamber, wherein the at least one catholyte chamber is coupled to at least one cathode, at least one anode membrane and at least one cathode membrane, wherein the anode membrane is adjacent to the at least one anode, wherein the cathode membrane is adjacent to the at least one cathode, at least one central chamber disposed between the at least one anolyte chamber and the at least one catholyte chamber. Hydrogen peroxide is produced by reduction of an oxygen-containing gas at the cathode.

Abstract: A membrane electrolysis cell comprising an anodic compartment and a cathodic compartment is described, wherein at least one of the two compartments contains an electrode fed with gas and a porous planar element is interposed between the membrane and the gas-fed electrode. A flow of chemically aggressive electrolyte crosses the porous planar element downwards under the effect of the gravity force. The planar element consists in a plastic element withstanding the aggressive operative conditions: The use of perfluorinated plastics such as ECTFE, PTEFE, FEP, PFA is preferred, even though they are strongly hydrophobic. When the gas-fed electrode is a cathode and the gas contains oxygen, the gas crosses the cathodic compartment upwardly so as to minimize the risk of hydrogen build up. The cell equipped with the oxygen cathode is particularly advantageous for the sodium chloride electrolysis.

Abstract: An electrolytic cell generates hydrogen peroxide and includes a reservoir for storing hydrogen peroxide generated by the cell. A controller is arranged to activate the cell and introduce stored hydrogen peroxide from the reservoir to the cell. This permits the concentration of a store of hydrogen peroxide to be refreshed as required, by introducing the stored hydrogen peroxide as the electrolyte in the cell. This counteracts the natural decay of the stored hydrogen peroxide. The pH of the hydrogen peroxide is controlled so that it is below a predetermined value. It has been found that hydrogen peroxide having a low pH, close to neutral, decays much more slowly than hydrogen peroxide having a more strongly alkaline pH.

Abstract: The present invention relates to a method of generating hydrogen or oxygen from an aqueous solution within a flow cell by applying a high frequency AC signal to the flow cell. The present invention further relates to an apparatus for generating hydrogen or oxygen from an aqueous solution, and a method of generating hydrogen peroxide in an aqueous solution.

Abstract: A device is disclosed for the generation of hydrogen peroxide. The device produces hydrogen peroxide on an as-needed basis through the use of electrolysis of water, wherein the hydrogen and oxygen are mixed in the electrolyzer, and the hydrogen and oxygen mixture in water are reacted in a reactor to produce hydrogen peroxide.

Abstract: An electrolytic cell for the production of hydrogen peroxide with faradic efficiency and a method for the production of highly pure hydrogen peroxide with high faradic efficiency are disclosed. The cell is provided with a separator of high hydraulic permeability and is equipped with an oxygen-fed gas-diffusion cathode and with an anode activated with a catalyst for oxygen evolution. The high faradic efficiency of hydrogen peroxide generation is allowed by the dilution of product hydrogen peroxide by the anolyte crossing the permeable separator, and by keeping the operating temperature at values below 50° C.

Abstract: An electrolytic cell for producing hydrogen peroxide includes an anode, a cathode and an intermediate membrane. The anode is associated with a first electrolyte and the cathode is associated with a second electrolyte. The use of two electrolytes associated with the respective electrodes permits the user to select the most suitable salt solutions for each electrode and so avoid production of gases and by-products unsuitable for a domestic environment. Thus, the electrolytic cell is suitable for use in an automatic dishwasher.

Abstract: The present invention relates to an electroionic apparatus for treating an aqueous solution, including a flow cell through which the aqueous solution may flow, and a high frequency AC power source. A pair of electrodes within the flow cell are in contact with the aqueous solution and coupled to the AC power source. The AC power source generates a signal that is transmitted to the electrodes to generate an electromagnetic field and an ionic current within the aqueous solution in the flow cell. Each electrode includes a plurality of perforations defined through the plate electrode. Electrodes within the flow cell may be formed of materials having a catalytic effect upon the electroionic reactions within the flow cell.

Abstract: A device is disclosed for the generation of hydrogen peroxide. The device produces hydrogen peroxide on an as-needed basis through the use of electrolysis of water, remixing hydrogen and oxygen in an appropriate ratio, and reacting the hydrogen and oxygen in water in a reactor.

Abstract: A real time in situ system and method for monitoring solutions, such as basic hydrogen peroxide (BHP) and other laser fuel solutions, is provided. Raman spectroscopy is applied to a solution of interest to provide substantially real time and in situ characterization of the solution. In one embodiment, OOH? and H2O2 Raman peaks are monitored in real time and in situ for determination of BHP composition.

Abstract: A method and apparatus for producing molecular oxygen in the excited singlet delta oxygen electronic state for use as an excited species reactant in a chemical laser. Flowtubes defined by permeable membranes are used to mix the gas and liquid phase reactants to generate singlet delta oxygen and also to separate the generated singlet delta oxygen from the liquid phase products and reactants thereby eliminating liquid reactant carryover.

Abstract: An industrially useful peroxo-carbonate is electrolytically produced using, as a raw material, carbon dioxide that is inexpensive and easily available. A process of producing a peroxo-carbonate, includes feeding a carbon dioxide gas into an electrolytic cell having a gas diffusion anode and a cathode, or feeding a liquid having a carbon dioxide gas dissolved therein into an electrolytic cell having an anode and a cathode, and electrolytically converting the carbon dioxide gas into a peroxo-carbonate. By properly setting up electrolytic conditions such as electrodes, a useful peroxo-carbonate can be produced with high current efficiency using inexpensive carbon dioxide as the raw material.

Abstract: A functional water containing a fluorine-containing component obtained by electrolyzing an aqueous solution containing fluoride ion using electrodes having conductive diamonds, a method of producing the same, and a method and an apparatus of rinsing electronic parts using the functional water as a rinsing water. The fluorine-containing component produced by electrolyzing the fluoride ion using the conductive diamond, has stronger rinsing effect than that of a fluorine-containing component obtained by electrolyzing the fluoride ion itself before electrolysis or the fluoride ion using other electrodes. Therefore, an amount of hydrofluoric acid used can greatly be decreased.

Abstract: The present invention provides an electroionic processing system having a high frequency alternating current (AC) power source for treating potable water, process water, wastewater, biosolids, sludge, primary effluent, secondary effluent, and other biochemical processing functions, including producing hydrogen peroxide and other useful chemicals. An electromagnetic field is generated and coupled to an electrolytic treatment apparatus by a direct coupling apparatus and method, a capacitive coupling apparatus and method, and an inductive coupling apparatus and method. The present invention further comprises a process controller and a plurality of analyzers for monitoring various treatment process variables to adjust and optimize the process as necessary.

Abstract: An electrolytic cell for producing chlorine and basic hydrogen peroxide suitably includes an anode partition and a cathode partition separated by a membrane. The cathode partition is divided into a catholyte compartment and a gas plenum by a gas diffusion cathode. The anode partition electrolyzes alkali chloride received from the laser to produce free chlorine and alkali ions. The catholyte partition reduces oxygen received from the gas plenum through the cathode, and produces alkaline peroxide from the oxidized components combined with alkali ions received through the membrane from the anode partition. The cell is particularly useful in a fuel regeneration system (FRS) for a chemical oxygen iodine laser (COIL).

Abstract: A method and apparatus for removing BHP contaminants (alkali hydroxide and H2O2) from a recycled aqueous alkali chloride solution stream before the stream is fed to a chloralkali cell so that the contaminants do not impair the operation of a chloralkali cell. Unwanted alkali hydroxide within the recycled alkali chloride brine solution is reacted with chlorine gas and converted into an alkali chloride, which is useful in the operation of the chloralkali cell, and oxygen gas, which is outgassed from the system. Any H2O2 remaining in the recycled stream after elimination of the alkali hydroxide is reacted with chlorine to form HCl and oxygen gas. The HCl raises the pH of the brine solution, after which the pH may be adjusted by the addition of supplemental alkali hydroxide.

Abstract: A method of generating basic hydrogen peroxide (BHP) fuel for a chemical oxygen-iodine laser (COIL) using stored alkali chloride, typically potassium chloride, and water. The alkali chloride and water are mixed to form a saturated or nearly saturated aqueous salt solution for use as an anolyte feed to a chlor-alkali cell. The chlor-alkali cell generates alkali hydroxide, hydrogen, and chlorine. Water and oxygen are reacted to form peroxide which is combined with the alkali hydroxide from the chlor-alkali cell to form a dilute solution of BHP, a mixture of hydrogen peroxide and alkali hydroxide, which dissociates into O2H? and ?OH. The BHP is concentrated and the molar ratio of hydrogen peroxide to alkali hydroxide is adjusted to 1:1 before the BHP is supplied to a COIL apparatus as fuel for the lasing process.

Abstract: This invention relates to a method and apparatus for the disinfection of water and wastewater contaminated with bacteria and other microorganisms. The apparatus includes an electrolytic flow cell including electrodes forming a part of flow pipe or open channel through which water or wastewater passes. The electrodes are formed of iron, stainless steel, carbon or copper and connected to a power supply voltage in the range of 20 to 100 volts and establishing a current in the range of 1 to 6 amperes. Disinfection results from either metal ions impacting microbial cells or through the generation of hydrogen peroxide, hydroxyl radicals and hypochlorous acid. When the electrodes are copper, toxic metal contamination limits are established through proper design of the flow cell. An ultrasonic transducer is connected to the electrodes and enhances hydroxyl radical generation.

Abstract: An electrolytic cell and process for the simultaneous production of hydrogen peroxide and hypochlorous ion. The electrolytic cell has an anode chamber housing an insoluble anode capable of oxidizing halide ion, a cathode chamber housing a gas diffusion cathode capable of oxidizing an oxygen-containing gas to produce hydrogen peroxide, a membrane separating the anode and cathode chambers, and means for supplying water containing halide ion to the anode chamber and an oxygen-containing gas and an electrolyte to the cathode chamber, whereby hypohalide and hydrogen peroxide are produced in the anode chamber and the cathode chamber, respectively. Also disclosed is a process for treating water using the electrolytic cell.

Abstract: An electrolytic cell and method of electrolysis for producing hydrogen peroxide at a moderate current density while preventing metal deposition on the cathode surface. A feed water from which multivalent metal ions have been removed and in which a salt of a univalent metal, e.g., sodium sulfate, has been dissolved in a given concentration is prepared with an apparatus for removing multivalent metal ions and dissolving a salt in low concentration. The feed water is supplied to an electrolytic cell. Even when electrolysis is continued, almost no deposition of a hydroxide or carbonate occurs on the cathode because multivalent metal ions are not present in the electrolytic solution. Due to the dissolved salt, a sufficient current density is secured to prevent an excessive load from being imposed on the electrodes, etc. Thus, stable production of hydrogen peroxide is possible over a long period of time.

Abstract: A process for the production of hydrogen peroxide solution from seawater as a starting material substantially free of effective chlorine or organic halogen compounds. An electric current is passed through an insoluble anode and an oxygen gas diffusion cathode while keeping the halide ion concentration of anolyte supplied to the anode chamber to a level not greater than 1 g/l. Hydrogen peroxide thus generated dissolves in the catholyte. Anodic oxidation of halide ions is suppressed, to thereby inhibit the production of effective chlorine.

Abstract: An electrolytic cell for producing chlorine and basic hydrogen peroxide suitably includes an anode partition and a cathode partition separated by a membrane. The cathode partition is divided into a catholyte compartment and a gas plenum by a gas diffusion cathode. The anode partition electrolyzes alkali chloride received from the laser to produce free chlorine and alkali ions. The catholyte partition reduces oxygen received from the gas plenum through the cathode, and produces alkaline peroxide from the oxidized components combined with alkali ions received through the membrane from the anode partition. The cell is particularly useful in a fuel regeneration system (FRS) for a chemical oxygen iodine laser (COIL).

Abstract: Using a solution mining procedure, an ore (10) is treated with a solution of acetic acid and hydrogen peroxide so as to form a leachate containing lead ions. Lead ions (and other metal ions such as zinc and manganese) are stripped (22, 24, 26) by solvent extraction from the leachate to form separate aqueous solutions. The aqueous solution containing lead ions is treated electrochemically in the anodic compartment of a separated electrochemical cell (42) to form a precipitate of lead oxide. Manganese dioxide can be produced similarly (72). A precipitate of zinc hydroxide can be formed in the cathode compartment of a separated electrochemical cell (56). In the cells (42, 72) extracting lead ions and manganese ions, the cathode compartment is used to generate hydrogen peroxide (for use in making the leachant), either directly or indirectly.

Abstract: Improved methods and devices for the synthesis of hydrogen peroxide employing redox catalysts in a gas diffusion electrode or membrane electrode assembly in a semi-chemical/electrochemical system for the production of high purity, stable, usually acidic, aqueous solutions of peroxide at high conversion efficiencies without requiring organic solvents.

Abstract: A process for the electrochemical preparation of hydrogen peroxide, in particular an aqueous hydrogen peroxide solution, by the electrochemical reaction of oxygen and hydrogen in a fuel cell. By increasing the thickness of the membrane layer in a membrane electrode unit (MEU) in the fuel cell, it is possible to substantially increase the concentration of H2O2 in the aqueous hydrogen peroxide solution obtained at the cathode.

Abstract: A method and apparatus for the generation and collection of an aqueous peracid solution at the cathode of a PEM electrolyzer. The electrochemical process introduces carboxylic acid (such as distilled table vinegar, lactic acid, citric acid or combinations) to the anode and a source of oxygen to the cathode. The PEM electrolyzer has a gas diffusion cathode having a cathodic electrocatalyst that is capable of hydrogen peroxide generation. The peracid solution is generated at the gas diffusion cathode and the solution is very pure and may be used for disinfecting or sterilizing various items or solutions. In a second embodiment, the carboxylic acid may be provided directly to the cathode, such as in the form of an acid vapor.