Effect of the main properties of membrane materials on denitrification of hydrogen-based membrane biofilm reactors (H2-MBfRs)

Abstract

Hydrogen-based membrane biofilm reactors using hollow-fiber membrane modules as their functional cores can play an important role in treating oxidizing pollutants. However, most studies have focused on pollutant removal, and few have investigated how membrane material properties affect reactor's operation. Here, we selected polyvinyl chloride (PVC) and polyvinylidene fluoride (PVDF) hollow fiber membrane materials with large differences in membrane surface properties to assemble the reactor, and investigated how the membrane properties affected nitrate removal and EPS secretion in MBfRs. The results showed that the membrane surface zeta potential and membrane contact angle had a certain positive impact on the NO3−-N removal rate and total EPS secretion in the MBfRs. When the contact angle (74.51–85.51°) and zeta potential (−12.5–4.5) increased, the biofilm on the membrane surface secreted more binding proteins (90.81–113.54 mg/gVSS), facilitating reactor biofilm growth, pollutant removal, and impact loads. Moreover, the properties of the experimentally selected PVC membrane material are more suitable for MBfR operation and are in line with the fundamental need for energy saving and emission reduction in modern society. This study provides a theoretical basis for the selection of membrane materials to enhance denitrification in H2-MBfRs, and an engineering foundation for reactors applications.