▎ 摘　　要

Sufficient efforts have been carried out to fabricate highly efficient graphene oxide (GO) lamellar membranes for heavy metal ion separation and desalination of water. However, selectivity for small ions remains a major problem. Herein, GO was modified by using onion extractive (OE) and a bioactive phenolic compound, i.e., quercetin. The as-prepared modified materials were fabricated into membranes and used for separation of heavy metal ions and water desalination. The GO/onion extract (GO/OE) composite membrane with a thickness of 350 nm shows an excellent rejection efficiency for several heavy metal ions such as Cr6+ (similar to 87.5%), As3+ (similar to 89.5%), Cd2+ (similar to 93.0%), and Pb2+ (similar to 99.5%) and a good water permeance of similar to 460 +/- 20 L m(-2) h(-1) bar(-1). In addition, a GO/quercetin (GO/Q) composite membrane is also fabricated from quercetin for comparative studies. Quercetin is an active ingredient of onion extractives (2.1% w/w). The GO/Q composite membranes show good rejection up to similar to 78.0, similar to 80.5, similar to 88.0, and 95.2% for Cr6+, As3+, Cd2+, and Pb2+, respectively, with a DI water permeance of similar to 150 +/- 10 L m(-2) h(-1) bar(-1). Further, both membranes are used for water desalination by measuring rejection of small ions such as NaCl, Na2SO4, MgCl2, and MgSO4. The resulting membranes show >70% rejection for small ions. In addition, both membranes are used for filtration of Indus River water and the GO/Q membrane shows remarkably high separation efficiency and makes river water suitable for drinking purpose. Furthermore, the GO/QE composite membrane is highly stable up to similar to 25 days under acidic, basic, and neutral environments as compared to GO/Q composite and pristine GO-based membranes.