Zahra Rahimi - Water and Wastewater Research Center (WWRC), Department of Applied Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran.
Ali Akbar Zinatizadeh - Water and Wastewater Research Center (WWRC), Department of Applied Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran.
Sirus Zinadini - Water and Wastewater Research Center (WWRC), Department of Applied Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran.

An innovative method based on the membrane bioreactor (MBR) technology was developed as a potential remedy for the water shortage. MBRs attracted much attention in the field of wastewater treatment and reuse. It is reported from many researchers that membrane bioreactor technology is feasible and an efficient method for the treatment of wastewater. However, MBRs are faced to membrane fouling which lead to short membrane lifetime and increase operating costs. Here we was modified polyethersulfone (PES) ultrafiltration membrane by blending of O-carboxymethyl chitosan/ Fe3O4 nanoparticles in a PES solution (14% polymer weight) and casted by a phase inversion process. Membranes with four different weight percentage of O-Carboxymethyl chitosan bound Fe3O4 magnetic nanoparticles (OCMCs-Fe3O4) to PES of 0.05, 0.10, and 1 wt. % were tested. The OCMCS-Fe3O4 nanoparticles were prepared by the binding of carboxymethyl chitosan (CC) onto the surface of Fe3O4 magnetic nanoparticles, which were prepared by co-precipitating method. The synthesized nanoparticles were characterized by the Fourier transform infrared (FTIR) technique. Moreover, OCMCS-Fe3O4 nanoparticales blend membranes were also characterized using scanning electron microscopy (SEM), and permeation tests. Antifouling performance was studied using activated sludge as a biological suspension and measuring the pure water flux recovery ratio (FRR). The 0.1 wt. % OCMCS-Fe3O4-PES membrane revealed the highest FRR value (89%). The results exhibited that addition of OCMCS-Fe3O4 nanoparticales lead to membranes with high pure water flux compared to the unmodified PES membrane. 

Membrane bioreactor, Antifouling, Ultrafiltration, Carboxymethyl chitosan-Fe3O4