Huron Tech Corp.

Stephen W Moran

John R Jackson

Timothy J Gallivan

Richard E Loftfield

Sam A Pirapakaran

Peroxydisulfuric acid and salts thereof are produced electrochemically from an aqueous acid sulfate solution in a cascading series of bipolar electrolytic cells having a cell body frames of polyvinyl chloride which are bonded with a vinyl ester polymer. An aqueous solution of peroxydisulfuric acid and salts thereof are withdrawn from the anode compartment of the last cell in the series, and metal impurities are removed by treatment with an ion exchange resin. Hydrogen peroxide is produced by hydrolyzing persulfuric acid and salts thereof. The sulfuric acid produced is recycled to the first cell in the series of cascading electrolytic cells.

Electrolysis cell and electrodes

An electrochemical process for the production of a hydroxide solution and a sulfate by the electrolysis of a waste aqueous mixture of oxidizable sulfur impurities in the anode compartment of at least one electrolytic cell while producing a hydroxide solution in the cathode compartment of the cell. The process is particularly applicable to the treatment of spent caustic solutions obtained by scrubbing a hydrocarbon process stream contaminated with oxidizable sulfur impurities. The electrolytic cell used in the electrolysis process of the invention can use either a porous membrane or a cationic permselective membrane to separate the anode and cathode compartments of the electrolysis cell. The electrolysis cell can be monopolar or bipolar and when bipolar, the bipolar electrodes if dissimilar, or the respective anode and cathode current collectors if dissimilar, which are attached thereto, are electrically connected by bonding with a conductive polymer or are joined by welding with or without an intermediate metal layer therebetween. Control of pH in the anolyte compartment of the electrolytic cell can be achieved by passing a selected amount of catholyte to the anolyte compartment. Pre-treatment with oxygen produced in the anolyte compartment of the cell avoids release of gaseous products from the anolyte compartment and increases process efficiency. Where the process is conducted in multiple electrolytic cells, such cells are hydraulically connected in a cascading series.

Electrolytic process for treating aqueous waste streams

Pulping chemicals and hemicellulose are recovered from a starting solution essentially free of lignin but containing a mixture of hemicellulose and caustic by electrolyzing this solution in the anolyte compartment of an electrolytic cell. By electrolysis, the concentration of caustic in the anolyte is decreased and the concentration of caustic in a catholyte of said cell is increased so as to allow recovery of about 60 to about 80 percent of the caustic present in the hemicellulose caustic starting solution.

Electrolysis process for removal of caustic in hemicellulose caustic

Pulping chemicals and hemicellulose are recovered from a starting solution essentially free of lignin but containing a mixture of hemicellulose and caustic by electrolyzing this solution in the anolyte compartment of an electrolytic cell. By electrolysis, the concentration of caustic in the anolyte is decreased and the concentration of caustic in a catholyte of said cell is increased so as to allow recovery, of about 60 to about 80 percent of the caustic contained in the hemicellulose caustic starting solution.

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Wilmington, NC, United States of America

Stephen W Moran