Evaluation of a novel composite chitosan-graphene oxide membrane for NOM removal during water treatment

This paper describes the fabrication and evaluation of a novel composite chitosan-graphene oxide (CS-GO) membrane for the drinking water treatment. In this study, different molecular weight (MW) ranges, and quantities, of CS were used to crosslink GO nanosheets layer by layer (LBL) on a commercial ultrafiltration membrane, thereby fabricating a range of composite CS-GO membranes. CS molecules greatly enhanced the binding force between GO nanosheets by providing both hydrogen-bonding, electrostatic interactions, and C-OH and C-N chemical bonds. The stability of the CS-GO membranes was verified by their immersion in different solutions for up to 60 days. The interlayer spacing of the CS-GO composite membranes, which influences their permeability and separation performance, was found to be dependent on the MW range and dosage of CS. The interlayer spacing increased with the CS MW, but decreased with CS dose. The corresponding interlayer spacing of different CS-GO membranes ranged between 1.03 and 1.12 nm with 0.2 mg CS and 0.88-0.91 nm with 0.5 mg CS. When filtering solutions containing three representative NOM components and samples of a real surface water, the separation performance of CS-GO membranes was very high (>95% rejection) bovine serum albumin (BSA), sodium alginate (SA), and humic acid (HA) but was much lower (40-50% TOC rejection) for a real surface water collected from Beijing Olympic Park Lake (OP Lake). The results of this study have demonstrated that novel composite CS-GO membranes can be fabricated using a facile cross-linking method at room temperature, with tunable properties, and have considerable promise for water treatment applications.

Automated summary

This study focuses on the fabrication and evaluation of a novel composite chitosan-graphene oxide (CS-GO) membrane for drinking water treatment. By crosslinking GO nanosheets layer by layer on a commercial ultrafiltration membrane with varying molecular weights and quantities of CS, a range of composite CS-GO membranes were created. These membranes showed high rejection rates for certain components in solution, indicating promise for water treatment applications.