Processes are provided for the kinetically efficient reduction of selenate species to selenide species using chromous ions in acidic solution. This reduction may advantageously be carried out in the presence of sulphate species, with selective selenate reduction in preference to the reduction of sulfate. The reduced selenate may be removed from the chromous-treated solution, for example by precipitation of a copper-selenide solid. The chromic ions formed by reaction of chromous ions in the reduction of selenate may also be removed from solution, for example by addition of a base to form an insoluble chromic hydroxide solid. The chromic hydroxide may be recycled to regenerate chromous ions, for example by electrolysis. In this way, systems are provided for continuously removing dissolved selenium from wastewater streams.

Methods for selenium removal from wastewater are provided using direct electrochemical reduction. Advantageously, the technique can efficiently and continuously treat weakly acidic wastewater (pH 4-7) with 0.001-10 mM Se(IV) concentrations in a weakly acidic solution. Embodiments of the invention include Se(IV) electrochemically removed from the aqueous phase through either a four- or six-electron pathway, with the former generating Se(0) directly attached to the electrode surface and the latter producing Se(-II) that is subsequently converted to Se(0). A key feature of these embodiments is the use of moderate heating to ensure the process takes place at an elevated temperature (e.g., temperatures above the amorphous-to-crystalline transition for Se(0)), which the inventors discovered results in the creation of conductive crystalline Se on an electrode surface, thereby avoiding self-limiting nature of prior techniques which result in insulative amorphous deposition of Se(0) on the electrode.

The present application relates to a method for removing a contaminant from wastewater from industrial fertilizer plant. The method comprises the steps of concentrating the wastewater, of electrolyzing the wastewater and of recirculating the electrolyzed wastewater to the fertilizer plant. The present application further relates to a system arranged to perform the method according to the present application.

The disclosure discloses an online resourceful treatment method of electroless copper plating waste solution. According to the disclosure, a copper catalyst is adopted to perform autocatalytic reaction on electroless copper plating waste solution in an autocatalytic reactor, copper simple substances are reduced from copper ions in the waste solution and recycled, the treated waste solution enters into a three-dimensional electrolyzer and a membrane filtration plant for further purification, the finally treated electroless copper plating waste solution meets water quality discharge standard, and the recovery rate of the copper simple substances can reach up to above 95%.

Disclosed are methods for using ionic liquids to extract metal ions from aqueous solution, and for subsequent recovery of the metal ions from the ionic liquids by electrochemical methods. The ionic liquids may be recycled and reused for further extraction.

The present application relates to a method for removing a contaminant from wastewater from industrial fertilizer plant. The method comprises the steps of concentrating the wastewater, of electrolyzing the wastewater and of recirculating the electrolyzed wastewater to the fertilizer plant. The present application further relates to a system arranged to perform the method according to the present application.

The present disclosure relates to an electrochemical flow reactor, such as a continuous flow electrochemical tubular reactor. This disclosure also relates to processes, systems, and methods comprising an electrochemical flow reactor. An electrochemical flow cell can comprise a reaction chamber, a first static mixer electrode, a second counter electrode, and a separator disposed between the first and second electrodes.

Processes are provided for the kinetically efficient reduction of selenate species to selenide species using chromous ions in acidic solution. This reduction may advantageously be carried out in the presence of sulphate species, with selective selenate reduction in preference to the reduction of sulfate. The reduced selenate may be removed from the chromous-treated solution, for example by precipitation of a copper-selenide solid. The chromic ions formed by reaction of chromous ions in the reduction of selenate may also be removed from solution, for example by addition of a base to form an insoluble chromic hydroxide solid. The chromic hydroxide may be recycled to regenerate chromous ions, for example by electrolysis. In this way, systems are provided for continuously removing dissolved selenium from wastewater streams.

Disclosed are polymer-coated surfaces encapsulating task specific ionic liquids (ILs), IL complexes, or oils. Also disclosed are polymer-coated surfaces, wherein the polymer comprises ILs or neutral ethylene diamine compounds. Also disclosed are methods of antimicrobial treatment, metal remediation, and gas absorption using polymer coatings encapsulating ILs, IL complexes, and oils or polymer coatings comprising ILs and neutral ethylene diamine compounds.

A method for selective adsorption of lead ions from heavy metal wastewater by electric field enhancement relating to a method for recovering lead ions from heavy metal wastewater. The method aims to solve the technical problems that it is difficult to recover heavy metals from a complex water environment in well-targeted manner and recovery purity is poor because of poor selectivity of the existing adsorbents. The adsorption selectivity to Pb.sup.2+ is enhanced under an electric field by applying a tannic acid@graphene oxide conductive aerogel material to water heavy metal electrochemical adsorption system as a conductive adsorbent. In the method, the conductive layer of the tannic acid@graphene oxide conductive aerogel material may be optimized through electrochemical reduction, so that the material has better conductivity, and has better selectivity to lead ions under an electric field.