Synthesis and characterization of graphene oxide-bovine serum albumin conjugate membrane for adsorptive removal of Cobalt(II) from water

Membranes with selective filtering capabilities are being designed globally, to tackle freshwater scarcity. In this study, we report the formulation of a bovine serum albumin (BSA) fabricated graphene oxide (GO) membrane for adsorptive removal of cobalt(II) from water. Large surface area along with abundant oxygen moieties upon interaction with biomolecules such as proteins, enable enhanced water purification. Free standing GO-BSA membrane was formulated by using covalent conjugating approach using cross—linkers, followed by vacuum-assisted filtration process. The chemical composition and structural morphology of the membrane was analyzed by different spectroscopic techniques. Water contact angle (WCA) studies exhibited hydrophilic behavior (58°) of GO which enabled efficacious conjugation of the protein to the graphitic derivative. Brunauer-Emmert–Teller (BET) surface area analysis showed an increase in surface area from 3.60 to 10.2 m2 g−1 in GO and GO-BSA conjugate, respectively. Further, the adsorption efficiency of cobalt by the prepared membranes was studied at different physical parameters such as concentration, pH, temperature and contact time of the adsorbent with the membrane. The GO-BSA membrane exhibited maximum adsorptive capacity of 184 mg/g at pH 6 which further amplified with rise in temperature from 25 to 35 °C. The reported work demonstrates formulation of a facile, low cost approach to efficiently remove cobalt ions from simulated wastewaters. The composed GO-BSA membrane will open new avenues for construction of portable water purification systems in future. Schematic depicting adsorptive removal of Cobalt from water by using covalently conjugated GO-BSA membrane by application of vacuum filtration