# US 5,702,587 A · Chemical and electrochemical regeneration of active carbon > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,587 A - Document ID: US5702587A - Status: Granted - Kind: A - Application number: 08/771,053 - Filed: 1996-12-20 - Granted: 1997-12-30 - Earliest claimed: 1996-12-20 - Assignees: Huron Tech Canada, Inc. - Inventors: Arthur L. Clifford; Dennis F. Dong; Timothy A. Mumby; Derek J. Rogers - Web page: https://patentgrep.com/patent/US5702587A ## CPC - C02F 1/4672: {by electrooxydation} - B01J 20/34: Regenerating or reactivating - C01B 32/36: Reactivation or regeneration - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} ## Abstract Method for the regeneration of active carbon having oxidizable, organic pollutants adsorbed thereon by electrochemical and chemical means and apparatus therefor. The method involves a desorption step prior to a decomposition step. Each step involves conducting electrolysis in a cell using the active carbon as a carbon bed electrode. It is advantageous to conduct the electrolysis in the presence of a transition metal or a chelate of a transition metal while feeding an oxygen containing gas to the electrolysis cell. ## Claims ### Claim 1 In a process for electrochemically regenerating the adsorptive capacity of a mass of activated carbon, said carbon comprising adsorbed, oxidizable, organic material, the improvement wherein said oxidizable, organic material is desorbed from said mass of carbon and substantially decomposed, said process comprising: A) providing electrolytic cell means comprising an aqueous electrolyte and electrodes, at least one of said electrodes consisting of said mass of carbon and adsorbed oxidizable, organic material, B) conducting electrolysis to effect desorption of said oxidizable, organic material, said aqueous electrolyte comprising hydrogen peroxide, while feeding an oxygen containing gas to said electrolytic cell, and C) conducting electrolysis to effect decomposition of said oxidizable, organic material, said aqueous electrolyte comprising hydrogen peroxide, a transition metal or ions thereof, and hydroxyl radicals, while feeding an oxygen containing gas to said cell. ### Claim 2 (depends on 1) The process of claim 1 wherein said electrolysis to desorb said oxidizable, organic material from said carbon is conducted at an alkaline pH, said electrolysis to decompose said oxidizable, organic material is conducted at a pH of about 1 to about 4, and said oxidizable, organic material is selected from the group consisting of halogenated and non-halogenated organic compounds, fuel hydrocarbons, and pesticides. ### Claim 3 (depends on 2) The process of claim 2 wherein said transition metal ions consist of ferrous ions, said oxidizable, organic material is selected from the group consisting of phenol, halogenated phenol, and halogenated or non-halogenated substituted phenol, and said oxygen containing gas is fed at a feed rate which provides at least 0.5 the stoichiometric amount of oxygen required to generate hydrogen peroxide based upon an electrical current required to obtain a selected potential on said mass of carbon. ### Claim 4 (depends on 1) The process of claim 1 wherein said electrolysis to desorb said oxidizable, organic material from said mass of carbon is conducted at an alkaline pH, said electrolysis to decompose said oxidizable, organic material is conducted in the presence of a complex of a transition metal and a chelating agent at a pH of about 8 or higher, and said oxidizable, organic material is selected from the group consisting of halogenated and non-halogenated organic compounds, fuel hydrocarbons, and pesticides. ### Claim 5 (depends on 4) The process of claim 4 wherein said transition metal consists of ferric iron, said oxidizable, organic material is selected from the group consisting of phenol, halogenated phenol, and halogenated or non-halogenated substituted phenol, said oxygen containing gas is fed at a gas feed rate which provides at least 0.5 the stoichiometric amount of oxygen required to generate hydrogen peroxide based upon an electrical current required to obtain a selected potential on said mass of carbon, and said chelating agent is selected from the group consisting of nitriloacetic acid, hemin, and ethylenediaminetetraacetic acid. ### Claim 6 An apparatus for regeneration of the adsorptive capacity of a mass of carbon comprising an adsorbed, oxidizable, organic material, said apparatus comprising electrolytic cell means comprising electrodes, at least one of said electrodes consisting of said mass of carbon and adsorbed, oxidizable organic material and an aqueous electrolyte comprising hydrogen peroxide, said electrolytic cell means effective for desorbing and decomposing said organic material by maintaining an electrical potential on said mass of carbon while feeding an oxygen containing gas to said cell. ### Claim 7 (depends on 6) The apparatus of claim 6 wherein said electrical potential on said mass of carbon is maintained negative, said electrolyte comprising transition metal ions is maintained at a pH of about 2 to about 3 or said electrolyte comprising a complex of a transition metal and a chelating agent is maintained at a pH of about 8 or higher. ### Claim 8 (depends on 7) The apparatus of claim 7 wherein said chelating agent is selected from the group consisting of nitriloacetic acid, hemin, and ethylenediaminetetraacetic acid. ### Claim 9 In a process for electrochemically regenerating the adsorptive capacity of a mass of activated carbon comprising an adsorbed, oxidizable, organic material, the improvement wherein said oxidizable, organic material is desorbed from said mass of carbon and substantially decomposed, said process comprising: A) providing electrolytic cell means comprising an aqueous electrolyte and electrodes, at least one of said electrodes consisting of said mass of carbon and adsorbed, oxidizable, organic material and B) conducting electrolysis to effect desorption and decomposition of said oxidizable, organic material, said electrolyte comprising hydrogen peroxide, while feeding an oxygen containing gas to said cell. ### Claim 10 (depends on 9) The process of claim 9 wherein said oxidizable, organic material is selected from the group consisting halogenated and non-halogenated organic compounds, fuel hydrocarbons, and pesticides. ### Claim 11 (depends on 10) The process of claim 10 wherein said oxidizable, organic material is selected from the group consisting of phenol, halogenated phenol, and halogenated or non-halogenated substituted phenol and said process comprises feeding an oxygen containing gas to said mass of carbon at a gas feed rate which provides at least 0.5 the stoichiometric amount of oxygen required to generate hydrogen peroxide based upon an electrical current required to obtain a selected potential on said mass of carbon.