# US 11,993,521 B2 · Treatment of aqueous matrices using electrolysis to produce soluble tin metal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,993,521 B2 - Document ID: US11993521B2 - Status: Granted - Kind: B2 - Application number: 17/860,275 - Filed: 2022-07-08 - Published: 2022-12-29 - Granted: 2024-05-28 - Earliest claimed: 2017-07-09 - Assignees: AMS Trace Metals, Inc. - Applicants: AMS Trace Metals, Inc. - Inventors: Vladimir Dozortsev; Richard Bacon; Jose Antonio Moreno - Web page: https://patentgrep.com/patent/US11993521B2 ## CPC - C02F 1/46104: {Devices therefor; Their operating or servicing} - C02F 1/4678: {of metals} - C02F 1/36: ultrasonic vibrations - C02F 1/66: by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58) - C02F 2001/46119: {Cleaning the electrodes} - C02F 2001/46133: {characterised by the material} - C02F 2101/20: Heavy metals or heavy metal compounds - C02F 2101/22: Chromium or chromium compounds, e.g. chromates - C02F 2201/4614: Current - C02F 2201/46145: Fluid flow - C02F 2209/006: comprising a software program or a logic diagram - C02F 2209/05: Conductivity or salinity - C02F 2209/06: pH - C02F 2209/40: Liquid flow rate - 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) ## Abstract This disclosure provides techniques for treatment of aqueous matrices using electrolysis to produce soluble metals. An aqueous matrix of interest is passed through an electrolysis device with at least one consumable electrode, which dissolves under applied current, transferring a desired reagent to the aqueous matrix of interest. In one embodiment, the electrolysis device is used in a water delivery network to passivate hexavalent chromium (Cr6) and/or convert it to trivalent chromium; the electrode can be made of food-grade metal tin, which is electrolyzed to form a stannous reagent, which then reacts with the Cr6. The disclosed techniques provide for Cr6 passivation without requiring the use of concentrated acids or other harmful substances. Long term reagent generation efficiency can be enhanced through the use of cleaning processes which maintain a fresh electrode surface in contact with the aqueous matrix of interest. ## Claims ### Claim 1 An apparatus to treat water to render inert target material in the water, and to prepare the water for potable use, the apparatus, comprising: an inlet to receive the water, an outlet, and a flow path coupling the inlet to the outlet; at least one electrode comprising food grade metal tin, the at least one electrode positioned to contact water within the flow path and to transfer electrolyzed tin from the at least one electrode into the water, in soluble form, at a rate that is a function of an electrical stimulus; an ultrasound transducer; and circuitry to regulate the electrical stimulus, as a function of at least one measured parameter, and to intermittently actuate the ultrasound transducer to de-passivate the at least one electrode according to a predetermined duty cycle, relative to application of the electrical stimulus to the at least one electrode. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein the electrical stimulus is regulated by the circuitry such that the at least one electrode experiences a current density of between 10 and 400 amps per square meter of surface area of contact between the at least one electrode and the water with the flow path. ### Claim 3 (depends on 2) The apparatus of claim 2 wherein the apparatus further comprises a flow rate meter and wherein the circuitry is to, responsive to an output of the flow rate meter, regulate the electronic stimulus as a function of a flow rate of the water, such that a rate of electrolysis of the tin provided by the at least one electrode is dependent on the flow rate. ### Claim 4 (depends on 1) The apparatus of claim 1 wherein the apparatus further comprises a pH detector, wherein the at least one measured parameter comprises a pH of the water, wherein the apparatus further comprises an actuator to control selective injection of a pH adjustment substance into the water, and wherein the circuitry is to control the actuator responsive to an output of the pH detector, such that the pH of the water within the flow path is regulated to fall within the range of 4.0 to 9.0. ### Claim 5 (depends on 1) The apparatus of claim 1 wherein the at least one measured parameter comprises a sensed concentration of the target material, wherein the circuitry is to receive a value representing a sensed concentration of the target material and wherein the circuitry is to regulate the application of the electrical stimulus to the at least one electrode in dependence on the sensed concentration. ### Claim 6 (depends on 1) The apparatus of claim 1 further comprising at least one of a filter or a trap positioned within the flow path, between the at least one electrode and the outlet, to separate tin from water output from the outlet, the filter being sized so as to separate particles having a size of greater than two microns. ### Claim 7 (depends on 1) The apparatus of claim 1 wherein the at least one electrode comprises two electrodes, each comprising the food grade tin, and wherein the electrical stimulus is applied to the two electrodes with an alternating polarity, in a manner that causes each of the two electrodes to reciprocally act as an anode and a cathode, as a function of the alternating polarity, such that each of the two electrodes is caused to alternately transfer electrolyzed tin into the water, in soluble form. ### Claim 8 (depends on 7) The apparatus of claim 7 wherein the alternating polarity is to be varied at a frequency corresponding to a value between 0.0016 and 1.0 hertz. ### Claim 9 (depends on 7) The apparatus of claim 7 wherein the two electrodes are embodied as respective, parallel plates, separated by a predetermined gap. ### Claim 10 (depends on 7) The apparatus of claim 7 wherein at least one of the two electrodes are embodied as one or more metal rods. ### Claim 11 (depends on 1) The apparatus of claim 1 wherein the at least one electrode comprises two electrodes, each comprising the food grade tin, wherein the apparatus comprises a sensor to detect degradation of at least one of the two electrodes, wherein the two electrodes are embodied in the form of a replaceable electrode module, and wherein the apparatus further comprises circuitry to automatically alert a human operator that it is time to replace the replaceable electrode module, in dependence on an output from the second sensor. ### Claim 12 (depends on 1) The apparatus of claim 1 wherein the duty cycle is such that the ultrasound transducer is actuated to clean the at least one electrode at least once per minute of application of the electronic stimulus. ### Claim 13 (depends on 1) The apparatus of claim 1 wherein the duty cycle is such that the ultrasound transducer is actuated to clean the at least one electrode intermittently for durations that are greater than one-tenth relative to corresponding durations of application of the electronic stimulus to control the electrolysis. ### Claim 14 A method of treating water to render inert target material in the water, and to prepare the water for potable use, the method comprising: via an inlet, receiving the water; providing an electrical stimulus to at least one electrode positioned within a flow path for the water received at the inlet, the at least one electrode comprising food grade metal tin, the at least one electrode positioned to contact the water within the flow path, the electrical stimulus to cause transfer of electrolyzed tin from the at least one electrode into the water within the flow path, in soluble form, at a rate that is a function of the electrical stimulus; with circuitry, regulating the electrical stimulus, as a function of at least one measured parameter, and intermittently actuating an ultrasound transducer to de-passivate the at least one electrode, according to a predetermined duty cycle, relative to application of the electrical stimulus to the at least one electrode; and outputting, from an outlet that receives the water from the flow path, treated water. ### Claim 15 (depends on 14) The method of claim 14 wherein the target material comprises a metal and wherein the method further comprises: causing a reaction between the electrolyzed tin and the metal which produces an insoluble material; and separating the insoluble material from the water. ### Claim 16 (depends on 15) The method of claim 15 wherein the target material is chromium-based and wherein the method further comprises causing electrolyzed tin to react with the chromium-based target material. ### Claim 17 (depends on 15) The method of claim 15 wherein the target material is selenium-based and wherein: the method further comprises measuring pH of the water, and with at least one actuator, controlling selective addition of a pH adjustment substance into the water, responsive to the measured pH, to maintain a pH of the water to be less than 3.0, contemporaneous with transfer of electrolyzed tin from the at least one electrode into the water within the flow path within the flow path; and the method is thereby adapted to cause electrolyzed tin is to cause a reaction with the selenium-based target material in the presence of a pH of less than 3.0. ### Claim 18 (depends on 15) The method of claim 15 wherein the target material is mercury-based, wherein the electrolyzed tin is to cause a reaction with the mercury-based target material, the reaction producing elemental mercury, and wherein separating the insoluble material comprises bubbling a gas through the water and filtering the gas to separate the elemental mercury from the gas. ### Claim 19 (depends on 15) The method of claim 15 wherein the target material is mercury-based, wherein the electrolyzed tin is to cause a reaction with the mercury-based target material, the reaction producing elemental mercury, and wherein separating the insoluble material comprises bubbling a gas through the water and filtering the gas to separate the elemental mercury from the gas. ### Claim 20 (depends on 14) The method of claim 14 wherein the electrical stimulus comprises a current, wherein providing the electrical stimulus comprises dynamically controlling a current source so as to adjust the current as a function of an amount of the electrolyzed tin to be added to the water, and wherein the method further comprises monitoring a voltage drop across the at least one electrode and taking at least one action from the group of notifying a human operator, increasing the current, or controlling actuation of the ultrasound transducer, responsive to a change in the voltage drop. ### Claim 21 (depends on 14) The method of claim 14 further comprising delivering water from the outlet to a potable water point of a potable water distribution system. ### Claim 22 (depends on 1) The apparatus of claim 1 wherein the apparatus comprises an online metal sensor, the online metal sensor adapted to measure tin in the water, and wherein the circuitry is adapted to, responsive to a value representing the measured tin: detect a condition where a reagent generation efficiency falls below a threshold; and control the ultrasound transducer to de-passivate the at least one electrode as a function of the detected condition. ### Claim 23 (depends on 5) The apparatus of claim 5 wherein the value corresponds to a non-zero, parts-per-billion level of concentration of the target material and wherein the circuitry to receive the value and to regulate the application of the electrical stimulus to the at least one electrode in dependence on the sensed concentration is adapted to: detect when the sensed concentration is below a predetermined threshold; control the at least one electrode so as to automatically turn on electrolysis when the sensed concentration is below the predetermined threshold. ### Claim 24 (depends on 1) The apparatus of claim 1 wherein the apparatus further comprises a current source, wherein the circuitry is to dynamically control the a current source so as to adjust a current, associated with the electrical stimulus, as a function of an amount of the electrolyzed tin to be added to the water, and wherein the circuitry is to monitor a voltage drop across the at least one electrode, and automatically take at least one action, from the group of notifying a human operator, increasing the current, or controlling actuation of the ultrasound transducer, responsive to a detected change in the voltage drop. ### Claim 25 (depends on 1) The apparatus of claim 1 wherein the apparatus further comprises a temperature detector, wherein the at least one measured parameter comprises a temperature of the water, and wherein the circuitry is to regulate the electrical stimulus as a function of the temperature of the water. ### Claim 26 (depends on 1) The apparatus of claim 1 wherein the at least one measured parameter comprises a reduction potential (RP) of the electrolyzed tin, and wherein the circuitry is to regulate the electrical stimulus as a function of the RP. ### Claim 27 (depends on 1) The apparatus of claim 1 wherein at least one of the inlet or the outlet is adapted for interface to a potable water distribution system, to transfer the water for potable use with the potable water distribution system.