Anti-fouling and anti-bacterial graphene oxide/calcium alginate hybrid hydrogel membrane for efficient dye/salt separation

Abstract

To improve the mechanical strength, antimicrobial and anti-swelling ability of calcium alginate hydrogel membrane, the graphene oxide/calcium alginate hybrid (GCA-H) hydrogel filtration membrane was prepared by ion cross-linking without organic solvent in this study. Meanwhile, the morphology, structure, and chemical bonding mechanism of membranes were characterized. Furthermore, we also investigated the mechanical strength, swelling behaviors, anti-bacterial, and anti-fouling properties of the GCA-H membrane. Since the excellent hydrophilicity, the GCA-H membrane showed high flux recovery rate (>97 %) based on the alternating filtration tests without cleaning the membrane. It was mentioned that the maximum stress-strain of the GCA-H membrane could reach 1.53 MPa, which was 2.34-fold more than that of the unmodified membrane. Due to the enhanced structure, it was beneficial to design the thinner membrane for further application. Moreover, we evaluated the impact of the operating parameters on dye/salt separation performance in this work. Generally, the rejections of Coomassie brilliant blue (CBB) and NaCl of GCA-H membrane were approximately 99 % and 8 %, respectively. Finally, we summarized the separation factor and nominalized flux for the dye/salt separation. The GCA-H membrane still maintained a good separation efficiency after being placed for 45 days. So the GCA-H membrane has a great potential in the selectivity separation process, which may provide a sustainable strategy for dye recycle.