Processes for producing olefins may include electrolyzing an aqueous solution comprising metal chloride, where electrolyzing the aqueous solution causes at least a portion of the metal chloride to undergo chemical reaction to produce a treatment composition comprising hypochlorite. The processes may further include contacting at least a portion of the treatment composition with the sour water at a pH from 8 to 12, where the sour water comprises sulfides and the contacting causes reaction of the sulfides in the sour water with the hypochlorite to produce a treated aqueous mixture comprising at least metal sulfates and metal chlorides, where the metal sulfates are present in the treated aqueous mixture as precipitated solids. The processes may further include separating the precipitated solids from the treated aqueous mixture to produce a treated effluent comprising at least the metal chloride.

Disclosed herein is a wastewater treatment reactor that makes use of activated carbon as the adsorbent. The wastewater treatment reaction is suitable for use in an electrochemical advanced oxidation process and includes a cathode and anode, where the cathode is arranged to incorporate activate carbon and carbon brushes. Also disclosed herein are methods making use of the reactor for adsorption of contaminants and its regeneration.

Copper-boron-ferrite (Cu—B—Fe) composites may be prepared and immobilized on graphite electrodes in a silica-based sol-gel, e.g., from rice husks. Different bimetallic loading ratios can produce fast in-situ electrogeneration of reactive oxygen species, H.sub.2O.sub.2 and .OH, e.g., via droplet flow-assisted heterogeneous electro-Fenton reactor system. Loading ratios of, e.g., 10 to 30 wt. % Fe.sup.3+ and 5 to 15% wt. Cu.sup.2+, can improve the catalytic activities towards pharmaceutical beta blockers (atenolol and propranolol) degradation in water. Degradation efficiencies of at least 99.9% for both propranolol and atenolol in hospital wastewater were demonstrated. Radicals of .OH in degradation indicate a surface mechanism at inventive cathodes with correlated contributions of iron and copper. Copper and iron can be embedded in porous graphite electrode surface and catalyze the conversion of H.sub.2O.sub.2 to .OH to enhance the degradation. Inventive cathodes can be stable catalytically after 20 or more cycles under neutral and acidic conditions.

An asymmetric system containing a first conductive polymer modified with a redox active moiety and a second conductive polymer modified with a surfactant is used for the separation of organic compounds from aqueous solutions. The asymmetric system has complementary hydrophobicity tunability in response to electrochemical modulations. For example, both materials are hydrophobic in their respective neutral states, therefore exhibiting affinity toward organic compounds. Application of a mild potential drives the desorption of the organic compounds and regeneration of the materials. The asymmetric system can be used in a cyclic fashion, through repeated electrical discharge or shorting of the two electrodes to program the capture of organics from a feed solution, and application of a potential to stimulate the release of the adsorbed organics.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

An electrolytic cell for treating wastewater comprises an anode assembly, a cathode assembly and at least one bipolar electrode assembly placed between the anode and the cathode assembly such that the anodes of the anode assembly and the cathodes of the cathode assembly are interleaved with the bipolar plates of the bipolar electrode assembly. Each bipolar electrode assembly comprises a series of bipolar electrodes which operate as an anode or as a cathode, stacked in a vertical direction along a threaded bolt made of an electrically conductive material such that the bipolar electrodes operating as anodes are oriented in an opposite direction to the bipolar electrodes operating as cathodes and have their ends overlapping over a predetermined portion and being separated by conductive spacers. In preferred embodiments, only the anodes and the bipolar electrodes operating as anodes are coated with catalyst which saves costs and simplifies the manufacturing process.

The present invention is directed to an electrochemical device for at least partially removing or reducing a target ionic species from an aqueous solution using faradic immobilization, the electrochemical device including at least one first electrode and at least one second electrode with different void fraction and surface area properties, due to differences in void fraction (also referred to as void ratio) of the at least one first and the at least one second electrode, water flows through an electrode with a high porosity, while the aqueous solution does not flow through an electrode with a low porosity. The asymmetry of the electrodes provides a desired voltage distribution across the device, which equates to a different voltage at each electrode, to control the speciation of the target ionic species at the anode and the cathode.

A stable three-dimensional core-shell metal-nitride catalyst consisting of NiFeN nanoparticles decorated on NiMoN nanorods supported on porous Ni foam (NiMoN@NiFeN), which functions as an oxygen evolution reaction catalyst for alkaline seawater electrolysis. It yields large current densities of 500 and 1000 mA cm.sup.−2 at overpotentials of 369 and 398 mV, respectively, in alkaline natural seawater at 25° C. Combined with an efficient hydrogen evolution reaction catalyst of NiMoN nanorods, current densities of 500 and 1000 mA cm.sup.−2 at low voltages of 1.608 and 1.709 V, respectively are achieved for overall alkaline seawater splitting at 60° C.

A capacitive adsorption module assembly is proposed. The capacitive adsorption module assembly includes a plurality of capacitive adsorption modules, each having a disk-shaped spacer configured to form a flow path through which feed flows, a cation exchange membrane attached to any one of an upper surface and a lower surface of the spacer, a first electrode attached to the cation exchange membrane, an anion exchange membrane attached to the other of the upper surface and the lower surface of the spacer, and a second electrode attached to the anion exchange membrane, wherein the capacitive adsorption modules are vertically stacked such that adjacent capacitive adsorption modules share or contact the first electrode or the second electrode, and at least one first terminal and second terminal passing through the stacked modules being provided, wherein the first terminal is electrically connected to the first electrode of an odd-numbered module, and the second terminal is electrically connected to the second electrode of an even-numbered module.

A method for operating a wastewater treatment system is disclosed wherein the wastewater treatment system comprises at least one electrochemical cell comprising dimensionally stable electrodes having the same catalyst composition, the electrodes being immersed in wastewater and being connected to a power supply and wherein the voltage at the power supply is monitored and the polarity of the electrochemical cell(s) is reversed when the recorded voltage increases by a predetermined voltage difference. The wastewater treatment system can comprise at least one electrochemical cell which is kept inactive while the active electrochemical cells are operating. The inactive cell(s) can be activated when all the electrodes of the active cells are consumed as indicated by another increase in voltage at the power supply after the polarity of the active cells has been once reversed.