Cross-linked graphene oxide membrane having high ion selectivity and antibacterial activity prepared using tannic acid-functionalized graphene oxide and polyethyleneimine

Abstract A covalently cross-linked graphene oxide (GO) membrane was prepared by a facile vacuum filtration method followed by a cross-linking process using tannic acid-functionalized GO (TA-GO) and hyperbranched polyethyleneimine (PEI). The TA-GO was prepared by a simple and environmentally friendly method using GO and a renewable plant-based polyphenol, tannic acid (TA), and it was covalently cross-linked by PEI via the reaction between catechol groups in TA and amine groups in PEI to form covalent bonds in a weak alkaline environment producing the cross-linked GO membrane. The cross-linked GO membrane showed excellent dimensional stability and ions separation performance. In particular, the cross-linked GO membrane containing TA showed excellent antibacterial activity against Escherichia coli ( E. coli ) due to the intrinsic bactericidal properties of the TA moieties. Furthermore, the membrane exhibited higher water flux and rejections toward NaCl and MgSO 4 than the commercial nanofiltration (NF) membranes.