Permeate flux recovery and removal foulant performances of hollow fiber polyvinylidene fluoride membrane bioreactor with peroxodisulfate activated iron (II) sulfate as a chemical cleaning agent

The main challenge with membrane bioreactors is fouling, which leads to decreased flux performance and a shortened membrane lifespan. This study aims to provide a solution for the flux recovery and removal of irreversible fouling on Polyvinylidene Fluoride (PVDF) membranes without damaging their structure using sulfate radicals. Sulfate radicals are formed via peroxodisulfate precursors that are activated by Fe2+. The membrane flux recovery and irreversible fouling ratio were 88.45-99.04% and 11.60-0.96%, respectively, at operating temperatures of 298-308 K. The PVDF membrane has been tested for microfiltration and washed up to 6 times per cycle. The mechanical properties, XRD, SEM-EDX, and ATR-FTIR characterization of the PVDF membrane after washing with PDS/Fe2+ did not show a negative effect on the PVDF structure. Additionally, the results of the kinetic and thermodynamic studies showed that washing with PDS/Fe2+ inhibited the formation of fouling particles on the membrane surface. Based on this study, sulfate radical oxidants with PDS precursors activated by Fe2+ can be applied as cleaning chemicals for PVDF membranes without damaging their structures.