β-cyclodextrin functionalized MWCNTs as a promising antifouling agent in fabrication of composite nanofiltration membranes

Abstract

In this research, the manufacture and properties of polyethersulfone (PES)-based mixed matrix nanofiltration (MM-NF) membranes modified with β-cyclodextrin functionalized multiwalled carbon nanotubes (β-CD/MWCNTs) were studied. The β-CD/MWCNTs nanocomposite was synthesized using the soft cutting method. Stable dispersivity of the resulting nanocomposite was checked for 12 h. Then, the membranes containing up to 1 wt% β-CD/MWCNTs were prepared using conventional phase inversion method. The impact of varied mass loadings of the β-CD/MWCNTs on the morphological features and performance of the amended membranes was evaluated. It was deduced that membrane hydrophilicity, porosity, pore size, water contents, dye rejection and antifouling capacity were noticeably improved after incorporating the β-CD/MWCNTs nanomaterials. In comparison with the bare membrane, the β-CD/MWCNTs amended membranes displayed higher hydrophilicity, and consequently pure water flux (PWF). Since β-CD can exploit the structure advantages of MWCNTs via enhancement of the dispersivity, devoting unique features to the β-CD/MWCNTs nanomaterial. The 0.1 wt% nanocomposite membrane sample revealed the highest pure water flux of 21.5 Kg/m2.h due to increase in pore size (5.0 nm). While, the membrane contributed with the β-CD/MWCNTs-0.5 revealed better performance in terms of dye rejection and antifouling capability than the bare and modified membranes. It indicated a dye rejection of above 92%, flux recovery ratio (FRR) of 89% and an irreversible resistance of 11.1%. The β-CD/MWCNTs-0.5 acted as a potential nanofiller in nanofiltration (NF) membranes improving their antifouling performance at different operational conditions.