Abstract: A method for electrodialysis is conducted in a multi-compartment, preferably a four compartment, electrodialysis cell configuration wherein an inexpensive source of protons, preferably from a strong inorganic acid enables the conversion of multivalent metal salts into valuable acid products, such as 2-keto-L-gluconic acid, a vitamin C precursor, and useful by-products, like calcium chloride.

Abstract: A method and apparatus are provided for electrolyzing water for enhanced production of oxygen, hydrogen and heat by the steps of (i) providing an electrochemical cell comprising an isotopic hydrogen storage cathode, an electrically conductive anode and an ionically conducting electrolyte comprising water, and (ii) impressing a repeating sequence of voltages across the cathode and anode comprised of at least two cell voltage regimes, a first cell voltage regime consisting of a voltage sufficient to enhance cathodic absorption of hydrogen, and a second cell voltage regime consisting of at least one voltage pulse which is at least two times the voltage of the first cell voltage regime for a total duration no greater than 0.10 seconds.

Abstract: A process for purifying and concentrating a gluconic acid derivative, such as 2-keto-L-gulonic acid, comprising introducing a non-viable and/or acidified fermentation medium or an in-vitro reactor medium comprising at least the gluconic acid derivative and/or salt thereof to electrodialysis thereby purifying and concentrating the gluconic acid derivative.

Abstract: A method for electrodialysis is conducted in a multi-compartment, preferably a four compartment, electrodialysis cell configuration wherein an inexpensive source of protons, preferably from a strong inorganic acid enables the conversion of multivalent metal salts into valuable acid products, such as 2-keto-L-gluconic acid, a vitamin C precursor, and useful by-products, like calcium chloride.

Abstract: Bipolar membrane electrodialysis methods for salt splitting polyvalent metal salts, where the metal cation can form substantially insoluble precipitates in the presence of hydroxyl ions can now be used in recovering acid and base values from a salt streams without precipitates fouling cell operation and causing shutdown. The introduction of an acid to the chamber where metal hydroxides would form inhibits their development or neutralizes formed solids, allowing salt splitting to continue. Salt splitting methods of the invention performed with a three compartment bipolar electrodialysis cell are useful in producing concentrated and purified acid forms, such as 2-keto-L-gluconic acid, H(KLG), a key intermediate in the production of ascorbic acid.

Abstract: A process for the continuous production of alkaline earth metal hydroxide by continuously providing an aqueous alkaline earth metal halide solution to the anode compartment and an aqueous alkaline earth metal hydroxide solution or water to the cathode compartment of an electrolytic cell in which an anode and a cathode are maintained in separate anode and cathode compartments, respectively, by a stable, hydrated, cation selective, hydraulically impermeable, electrically conductive membrane interposed between said anode and said cathode; electrolyzing the alkaline earth metal halide solution; and continuously removing alkaline earth metal hydroxide solution and hydrogen from the cathode compartment and halogen from the anode compartment. The membrane is a film of a fluorinated polymer with pendant side chains containing sulfonyl groups present as ion exchange sites and attached to carbon atoms which have at least one fluorine atom attached thereto.

Abstract: A system for screening and measuring the effectiveness of catalysts, comprising an electrolytic cell having a counter electrode comprising a plurality of segmented anodes, each of the anodes electrically isolated from each other, and a catalyst support adapted for holding an associated plurality of cathodes, where each cathode is operatively arranged to function as a working electrode when a discrete catalyst is deposited thereon, wherein the catalyst support positioned between the counter electrode and the working electrodes, and, means for measuring current in each of the plurality of segmented anodes, where the current is an indication of effectiveness of each discrete catalyst.

Abstract: Bipolar membrane electrodialysis methods for salt splitting polyvalent metal salts, where the metal cation can form substantially insoluble precipitates in the presence of hydroxyl ions can now be used in recovering acid and base values from a salt streams without precipitates fouling cell operation and causing shutdown. The introduction of an acid to the chamber where metal hydroxides would form inhibits their development or neutralizes formed solids, allowing salt splitting to continue. Salt splitting methods of the invention performed with a three compartment bipolar electrodialysis cell are useful in producing concentrated and purified acid forms, such as 2-keto-L-gluconic acid, H(KLG), a key intermediate in the production of ascorbic acid.

Abstract: A process for purifying and concentrating a gluconic acid derivative, such as 2-keto-L-gulonic acid, comprising introducing a non-viable and/or acidified fermentation medium or an in-vitro reactor medium comprising at least the gluconic acid derivative and/or salt thereof to electrodialysis thereby purifying and concentrating the gluconic acid derivative.

Abstract: The present invention relates to electrochemical methods for the recovery of ascorbic acid from an ascorbate salt without the co-generation of a waste salt stream and while maintaining high conductivity of the electrochemical cell thereby providing for quantitative conversion of the salts to ascorbic in both batch and continuous mode processes. In one embodiment the feed stream comprising an ascorbate salt is dissociated under the influence of an electric field and subjected to water splitting electrodialysis. The ascorbate ion combines with a proton and the salt cation combines with a hydroxyl ion to form ascorbic acid and base, respectively. The feed stream further comprises an inorganic salt which maintains high conductivity in the cell, facilitates quantitative conversion of ascorbate salts to ascorbic acid in both batch and continuous mode processes, and promotes precipitation and crystallization of ascorbic acid as a fine powder.

Abstract: An electrochemical gas sensor is provided, the use of which permits quantitative measurement of volatile gas contaminants in an atmosphere being monitored, generally at ambient temperatures below 100.degree. C. The sensor is constructed of a sensor electrode and a reference electrode on a separator in such a manner as to be exposed to the atmosphere which is sensed for gaseous contaminants. In an alternative embodiment, the sensors can be covered with a selective filter which will selectively allow only small molecule toxic gases to pass for sensing by the sensor electrode while excluding larger interfering gas molecules. In another alternative embodiment, a multiple layer electrochemical gas sensor detects the presence of volatile gas contaminants in a sample gas as well as humidity, temperature, and/or pressure of the gas sample.

Abstract: Improved electrochemical processes for producing high purity grades of hydrogen iodide without developing cell fouling iodine solids through oxidation of iodide at the anode back migrating through ion exchange membrane into anolyte compartment. Two and three compartment electrochemical cells have anolyte solutions with chemical agents for oxidizing back migrating iodides to soluble iodine species to avoid build up of iodine solids on key cell components. Other embodiments include processes with undivided electrochemical cells fitted with hydrogen depolarized anodes, optionally operating electrogeneratively producing at least some of its own power requirements while simultaneously producing HI, or processes of making high purity HI with multi-phase aqueous/non-aqueous anolytes for solubilizing iodine solids as they develop in the anolyte compartment.

Abstract: Methods for the electrolysis of aqueous solutions of alkali metal carbonates and bicarbonates for the production of alkali metal hydroxides at current efficiencies of >85 percent without the simultaneous co-production of halogen or acid can be performed at very low, commercially attractive cell voltages and at high current densities in single or two solution compartment cells with carbon dioxide as the only substantive co-product by maintaining cell pH at >7. The methods are also especially suitable for retrofitting existing chlor-alkali facilities for shifting the balance of production in favor of caustic soda at peak demands. The methods may also be performed with fuel cell configurations for even more attractive operating economics.