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Abstract: pH-controlled separation of AAs was achieved by electro-membrane cell (EMC) with three compartments (central, comp. 1 and comp. 2). EMC is based on the principles of electrodialysis (ED) using indigenous cation-exchange and anion-exchange nanofilter (C-NF and A-NF, respectively). Water permeabilities (1.1–1.5mh−1 bar−1) and molecular cut-off (MWCO) values (400–500Da) for C-NF and A-NF, were suggested their nanofilter (NF) nature. Electrochemical properties of these membranes confirmed their suitability for EMC. Chronopotentiometric studies revealed the electro-transport of positively charged lysine (LYS+) and negatively charged glutamic acid (GLU−) across C-NF and A-NF, respectively, at pH: 6.1 under applied voltage. While glycine at its pI (pH: 6.1) remained immobile. Thus, separation of AAs (ternary mixture) by iso-electric point (pI) focusing of one component was proposed. Under optimized experimental conditions (i.e. at 4.0V constant applied voltage, pH: 6.1 for 0.05M equi-molar LYS–GLU–GLY mixture), about 4.0kWhkg−1 of AA separated energy consumption, 82% current efficiency and 90% product recovery showed the economic and technical feasibility of EMC for industrial exploitation. [Copyright &y& Elsevier]

Laser-induced graphene (LIG) is a three-dimensional porous carbon material prepared by direct laser writing with a CO 2 laser on various polymers in an ambient atmosphere, leading to electrically conductive, low fouling coatings. Recently, LIG has been synthesized on porous supports, which led to highly permeable and porous separation filters and LIG composites have greatly improved the stability. On the other hand, graphene oxide (GO) has emerged as a promising 2D nanomaterial to coat porous or non-porous polymer membrane supports resulting in separation membranes with enhanced separation and surface properties. Here, we report a robust, hybrid LIG-GO membrane fabricated by filtration and crosslinking of GO onto the LIG membrane support, generating ultrafiltration membranes with tailored performance. Increasing the amount of crosslinked GO on the LIG surface resulted in increased rejection of bovine serum albumin (BSA) up to 69%, and bacterial rejection was increased from 20 to 99.9%, which agreed with the measured molecular weight cut-off determination that approached ~ 90 kDa as the GO content increased. Higher flux recovery ratios and lower BSA adsorption were seen with LIG-GO membranes, and the hybrid membranes showed comparatively good antifouling. These composite membranes showed 83% less biofilm growth compared to a typical polymer ultrafiltration membrane under non-filtration condition. Noteworthy is that the LIG supporting layer maintained its electrical conductivity and the LIG-GO membrane used as electrodes showed complete elimination of bacterial viability with potent antimicrobial killing effects when treated with mixed bacterial culture. In cross-flow filtration, LIG-GO membranes with 3V anodic electric field showed 11% improvement of flux as compared to typical polymer ultrafiltration membrane. The LIG-GO membranes expand possibilities for the use of LIG in membrane separation applications, especially ultrafiltration. Carbon-based antifouling, electrically conductive ultrafiltration membranes were fabricated using laser-induced graphene membrane supports and crosslinked graphene oxide. Image 1 • laser-induced graphene (LIG) integrated into composite membranes. • LIG composites with crosslinked graphene oxide(GO) show ultrafiltration properties. • LIG-GO composite membranes stable under extended sonication at low and high pH. • Membranes electrically active, showing low fouling and bacterial killing effects. • LIG-GO more biofouling resistant than commercial UF membrane in cross-flow testing. [ABSTRACT FROM AUTHOR]

BaCO 3 nanoparticles (NPs) (20 and 100 nm) were prepared using poly(vinyl pyrrolidone) (PVP) as stabilizer. The prepared NPs showed high adsorption capacity for Mg 2 + in presence of other cations (Na + , Ca 2 + etc.). BaCO 3 nanoparticles embedded sulphonated poly(ether sulfone) (SPS) membranes were prepared, which showed Mg 2 + retentive and cation selective properties. These membranes exhibited good thermal, mechanical, and chemical stabilities along with conductivity and ion-exchange capacity due to SPS matrix. Mg 2 + retentive nature of these membranes was attributed to the embedded BaCO 3 NPs. Further, SPS-NPE membrane was assessed suitable for electro-separation process. Electrodialytic studies confirmed very high retention values for Mg 2 + in comparison with Na + and Ca 2 + . The energy consumption of proposed process suggested suitability of these membranes for separation/recovery of Mg 2 + from natural water resources. [ABSTRACT FROM AUTHOR]