Severe fouling to poly(vinylidene fluoride) (PVDF) membrane is usually caused as filtrating the papermaking wastewater in the ultrafiltration (UF) process. In the paper

fouling behavior and mechanism were investigated

and the low-concentration polyvinyl alcohol (PVA) contained in the sedimentation tank wastewater was found as the main foulant. Consequently

the corresponding cleaning approach was proposed. The experiment and modeling results elaborated that the fouling mode developed from pore blockage to cake layer along with filtration time. Chemical cleaning conditions including the composition and concentration of reagents

cleaning duration and trans-membrane pressure were investigated for their effect on cleaning efficiency. Pure water flux was recovered by over 95% after cleaning the PVDF membrane using the optimal conditions 0.5 wt% NaClO (as oxidant) and 0.1 wt% sodium dodecyl benzene sulfonate (SDBS

as surfactant) at 0.04 MPa for 100 min. In the chemical cleaning method

hypochlorite (ClO

-

) could first chain-scissor PVA macromolecules to small molecules and SDBS could wrap the fragments in micelles

so that the foulants were removed

from the pores and surface of membrane. After eight cycling tests

pure water flux recovery maintained above 95% and the reused membrane was found intact without defects.