Low-cost microbiological purification using a new ceramic disk filter functionalized by chitosan/TiO2 nanocomposites

The intaking of water with undesired substances may cause many water-borne diseases. It is required to develop efficient and low-cost water purification technologies for developing countries. In this study, a new ceramic disk filter functionalized by chitosan/TiO2 nanocomposites (CT-CDF) for bacterial removal from drinking water was investigated. The characterization results showed that the chitosan/TiO2 nanocomposites were attached to the surface of CDFs. The optimal conditions for producing CT-CDFs were 0.2 g of chitosan, 0.05 g of TiO2, and 0.04 g of coating amount, respectively. The factorial analysis indicated that the illumination time and lamp power promoted the reduction of E. coli, but influent E. coli concentration showed a negative effect. There was an interaction between lamp power and influent E. coli concentration. The bacterial removal of CT-CDFs was due to the retention by irregular pores in CT-CDF, the cellmembrane damage caused by the attached chitosan/TiO2 nanocomposites, and the oxidative stress in cells from ROS generated by nano-TiO2. Prolonging illumination time and increasing lamp power can promote the photocatalysis, resulting in the enhanced removal efficiency of CT-CDFs. The results of this study can provides not only an insight into the bacterial removal involving multiple mechanisms, but also an economic-feasible solution for resolving the water safety issues in developing countries.