Antibacterial properties of chitosan chloride-graphene oxide composites modified quartz sand filter media in water treatment

In order to control bacterial pollution in water treatment, it is necessary to prepare efficient antibacterial materials. Novel chitosan chloride-graphene oxide (CSCl@GO) composites were prepared via a one-step solution blending method. The composites were characterized by FT-IR, XRD and TEM techniques. The antibacterial mechanism of CSCl@GO composites was investigated using gram-negative bacteria E. coli and gram-positive bacteria S. aureus as two model microorganisms. The antibacterial properties of CSCl@GO composites for complex bacteria in the cooling water system were researched. In addition, the CSCl@GO composites modified quartz sand filter media (CSCl@GO/QS) were synthesized. The antibacterial performance of CSCl@GO/QS filter media in secondary effluent of domestic sewage was also investigated. The results showed that E. coli and S. aureus were completely inactivated after treatment with 100 mg·L^-1 of CSCl@GO composites for 15 min. When adding CSCl@GO composites to E. coli or S. aureus suspension, the protein leakage was 12.7 or 9.9 times higher than that in the blank experiment after 12 h. The antibacterial rate of CSCl@GO composites in circulating cooling water reached 95.74% when the mass fraction of GO was 0.6%. After the CSCl@GO/QS filter media were backwashed for 3 times, the antibacterial rate could still be above 90%.