EXTERIOR SURFACE CHARACTERIZATION OF THE NOVEL SURFACE MODIFIED PES HOLLOW FIBER MEMBRANE APPLICABLE IN BIOREACTOR

Exterior surface characteristics of the submerged hollow fiber (HF) membranes are believed to have a significant impact on the fouling rate within the filtration process in a bioreactor used for wastewater treatment. Most of the interactions among the organics, particulate particles, and microorganisms occur at the interface of the membrane surface and activated sludge (AS). Despite the numerous advantages exhibited by polyethersulfone (PES) hollow fiber (HF) membranes, their extensive utilization in wastewater treatment applications is substantially hindered by the prevalent issue of biofouling, which stands as the primary challenge in membrane bioreactors (MBR). Accordingly, the aim of this investigation is to characterize the exterior surface of the PES HF membrane after a two-step modification process involving the biomimetic-based polydopamine nanospheres and in situ synthesis and immobilization of zinc oxide nanoparticles (ZnO NPs), and to assess its impact on the permeability and fouling rate of the membrane in an MBR. The surface morphology and elemental analysis of the surface functionalized PES HF membranes were assessed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Antimicrobial properties of the surface-modified PES HF membranes were tested under dynamic contact conditions based on the ASTM E2149 after inoculation with Staphylococcus spp. strain CCM 2446 and Escherichia coli strain CCM 7395 (supplied by Masaryk University in Brno). Finally, the permeability of the membranes beneath deionized (DI) water and activated sludge was evaluated as well. The results of this study can aid in the development of PES HF membrane performance used for wastewater treatment applications.