Sulfonated reduced graphene oxide modification layers to improve monovalent anions selectivity and controllable resistance of anion exchange membrane

Single Layer 2D Crystals for Electrochemical Applications of Ion Exchange Membranes and Hydrogen Evolution Catalysts

“…In addition, AEMs are based on polymeric quaternary ammonium groups which usually have highly toxic preparation techniques . In addition, problems like poor thermal and mechanical stability of these membranes have led researchers to search for other AEMs with good ion conductivity …”

“…However, a higher degree of sulfonation leads to membrane swelling and eventual dissolution. Graphene as a filler material in the polymer matrix has been investigated to achieve flexible and freestanding composite membranes . Work based on composite membranes of these multilayer graphene or reduced graphene oxide as IEMs will be summarized in this section with focus on their components, synthesis process and performance.…”

Integrated Valorization of Desalination Brine through NaOH Recovery: Opportunities and Challenges

“…Similar to ED,S ED is driven by an applied electrical force,w hich allows for the transport of the ions through charge-selective membranes;h owever, it can also separate the monovalent and divalent ions in the brine.A nS ED system is typically composed of an anode,acathode,a nionexchange membranes (AEMs), cation-exchange membranes (CEMs), and monovalent selective-to-anion (MVA) membranes ( Figure 3). [11,39] Theions experience an electrical force resulting from the potential difference between the anode and cathode,c ausing the anions to move toward the anode while the cations move toward the cathode.C EMs are negatively charged and transport cations and reject anions;onthe other hand, AEMs are positively charged and transport anions and reject cations.S ince the AEMs and CEMs are generally nonspecific,b oth divalent and monovalent ions are able to pass through the membranes.T herefore,M VA membranes are added in SED systems to transport monovalent anions while rejecting divalent anions.T he alternating sequence of MVA, AEM, and CEM produces monovalent anion-rich, divalent anion-rich, and dilute brine solutions.…”

“…Current research has explored the technical feasibility of SED by producing MVAm embranes through surface modifications and testing the membranes in electrodialysis systems,inwhich higher permselectivity values were observed in comparison to the unmodified membranes. [11,[39][40][41][42] Thea pplication of the MVAm embranes demonstrated the various methods of producing the membranes as well as the technologysc apability of separating ions based on their valence charge. In addition to MVAmembranes,monovalent selective-tocation (MVC) membranes can be included to separate monovalent and divalent cations.…”

“…(2)] is likely to be much more energy intensive,w ith the best oxygen evolution catalysts currently requiring overpotentials around 250 mV to achieve 10 mA cm À2 in alkaline or acidic conditions. [39] Oxidation of water has been widely studied owing to its potential use in various energy-related processes such as hydrogen production, carbon dioxide valorization, or metalair batteries,but similarities in the intermediates cause scaling relations in their binding energies that lead to afundamental limitation of the minimum overpotential required. [56] BMED and DE systems are even more challenging than typical applications of the oxygen evolution reaction (OER) because the reaction must proceed in acidic conditions and the competing chlorine evolution reaction (CER) must be suppressed, as shown schematically in Figure 4.…”