Water Remediation Aided by a Graphene-Oxide-Anchored Metal Organic Framework through Pore- and Charge-Based Sieving of Ions

Herein, a unique reversible addition-fragmentation chain transfer (RAFT)-synthesized antibacterial copolymer was designed to target key requirements such as stringent and quick response toward bacteria and quick reversible response toward fouling using a multilayered assembly. In order to render the membrane assembly selective toward ions, a unique phosphonium-conjugated graphene oxide (P(+)GO)-anchored copper- and trimesic-acid-based metal organic framework (CuMOF) was sandwiched between the RAFT-synthesized polymer and a commercial reverse osmosis (RO) support. The sandwich architecture exhibited excellent antibacterial properties for both Gram-positive and Gram-negative bacterial cells. The membranes also retained an unimpeded flow of water even after longer continuous runs. The engineered active layer was excellent in rendering reversible antifouling against bovine serum albumin with 98.8% flux retention. The nanoexclusions/channels offered by the P(+)GO-anchored CuMOF, sandwiched as an interlayer, though reduced the flux as compared to the support RO but manifested in an exemplary 99.9% salt removal for a formulation composed of monovalent and divalent ions through synergistic charge- and pore-based sieving. This multilayered assembly is bactericidal, is resistant to scaling unlike the base RO support, and shows excellent ion-sieving characteristics that makes it a potential candidate in water remediation