Journal of Applied Research in Water and Wastewater 1 (2014) 13-17 Please cite this article as: Z. Rahimi, A.A. Zinatizadeh, S. Zinadini, Preparation and characterization of a high antibiofouling ultrafiltration PES membrane using OCMCS -Fe3O4 for application in MBR treating wastewater, Journal of Applied Research in Water and Wastewater, 1(1), 2014, 13-18. Page | 13 Journal of Applied Research in Water &Wastewater Journal homepage: www.arww.razi.ac.ir Original paper Preparation and characterization of a high antibiofouling ultrafiltration PES membrane using OCMCS-Fe 3 O 4 for application in MBR treating wastewater Zahra Rahimi, Ali Akbar Zinatizadeh*, Sirus Zinadini Water and Wastewater Research Center (WWRC), Department of Applied Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran. ARTICLE INFO ABSTRACT Article history: Received 13 October 2013 Received in revised form 13 December 2014 Accepted 25 March 2014 Available online 18 March 2014 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. © 2014 Razi University-All rights reserved. Keywords: Membrane bioreactor Antifouling Ultrafiltration Carboxymethyl chitosan-Fe3O4 1. Introduction Due to increasing the water source shortage concerns, recently technology of membrane bioreactors (MBRs) is become an attractive option for the treatment and reuse of municipal and industrial wastewaters because of many favorable features that it offers: high quality of processed water, reduction in excess sludge, controllability of solids and hydraulic retention time, and minimization possible in required footprint (Le-Clech et al. 2010; Kraume et al. 2010; Judd. 2008). However, a major issue associated with MBR is membrane fouling that the bioreactor suffers from it. Complicated interactions between membrane material and various components of activated sludge mixed liquor result in biofouling of the membrane. Unlike physical or chemical fouling, biofouling can irreversibly damage membrane surfaces and often causes permanent permeability loss, which makes the MBRs for wastewater treatment costly (Lee et al., 2013; Flemming et al. 1991; Liu et al. 2010). Therefore, it is highly desirable to have a membrane with antifouling capability, or anti- biofouling membrane. A membrane material among synthetic polymers that has widely been used in membrane processes is polyethersulfone (PES), because of having many good physico-chemical characteristics such as desirable thermal and mechanical properties as well as chemical stability and easy processing (Marchese et al. 2003). However, the natural hydrophobicity of PES due to its structure is caused it is not immune from the biofouling problem and provides a low membrane flux and poor anti- fouling properties (Akar et al. 2013). Therefore, various approaches have been taken to increase the hydrophilic properties of PES either by chemical or physical modifications including blending [Yi et al. 2010; Teli et al. 2012), coating (He et al., 2008) and grafting (Yune et al. 2011; Deng et al. 2009). Akar and coworker (2013), prepared polyethersulfone ultrafiltration membranes with selenium and copper nanoparticles and investigated the morphology, performance and anti-fouling properties of membranes. It was shown that the blending membranes with nanoparticles are considered to be suitable for the prevention of biofouling. Yu et al. (2013) were prepared SiO2@N-Halamine/polyethersulfone (PES) ultrafiltration membranes by phase inversion method. It was reported that hybrid membranes showed good antifouling and antibacterial properties, which might expand the usage of PES in water treatment and also could make some potential contributions to membrane antifouling. In the another study by Huang et al. (2012), mesoporous silica (MS) particles was synthesized as inorganic fillers, and blended with polyethersulfone (PES) to achieve nanocomposite membranes with antifouling properties. Corresponding author E-mail: zinatizadeh@razi.ac.ir