Effect of TiO 2 nanoparticles on fouling mitigation of ultrafiltration membranes for activated sludge filtration

Abstract

Membrane bioreactors (MBRs) have been widely used as advanced wastewater treatment process in recent years. However, MBR system has a membrane fouling problem, which makes the system less competitive. Thus there have been great efforts for fouling mitigation. In this study, two types of TiO 2 immobilized ultrafiltration membranes (TiO 2 entrapped and deposited membranes) were prepared and applied to activated sludge filtration in order to evaluate their fouling mitigation effect. Membrane performances were changed by addition of TiO 2 nanoparticles to the casting solution. TiO 2 entrapped membrane showed lower flux decline compared to that of neat polymeric membrane. Fouling mitigation effect increased with nanoparticle content, but it reached limit content above which fouling mitigation did not increase. Regardless of polymeric materials, membrane fouling was mitigated by TiO 2 immobilization. TiO 2 deposited membrane showed greater fouling mitigation effect compared to that of TiO 2 entrapped membrane, since larger amount of nanoparticle was located on membrane surface. It can be concluded that TiO 2 immobilized membranes are simple and powerful alternative for fouling mitigation in MBR application.