213 Chitosan/Polyethersulfone Composite Nanofltration Membrane for Industrial Wastewater Treatment A. Ghaee 1*, M. Shariaty-Niassar 2 , J. Barzin 3 , A. F. Ismail 4 1- Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, I. R. Iran 2- Department of Chemical Engineering, College of Engineering, University of Tehran, Tehran, I. R. Iran 3- Department of Biomaterials, Iran Polymer and Petrochemical Institute, Tehran, I. R. Iran 4- Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia (*) Corresponding author: ghaee@ut.ac.ir (Received:15 Sep. 2013 and Accepted: 08 Oct. 2013) Abstract: Chitosan/polyethersulfone (CS/PES) composite membrane was prepared from casting chitosan solution on polyethersulfone substrate membrane. The Substrate membrane was prepared by phase inversion technique using polyethersulfone (PES) and dimethylacetamide (DMAc) as solvent with and without the addition of polyvinylpyrrolidone (PVP) as pore-forming agent. The effects of the composition of the casting solution on membrane morphology and water permeation were investigated. The membrane prepared from 15 wt % PES with 2.25 wt % PVP demonstrated better water permeability compared to other compositions. CS/PES composite membrane fux and retention were 5.2 lit/m 2 hr and 76.15%, respectively. The mean pore size of the composite membrane was calculated as 0.99 nm. Keywords: Chitosan; Composite membrane; Molecular weight cut off; Nanofltration; Thermal analysis. Int. J. Nanosci. Nanotechnol., Vol. 9, No. 4, Dec. 2013, pp. 213-220 1. INTRODUCTION The membrane process between UF (Ultrafltration) and RO (Reverse Osmosis) is called nanofltration (NF) and has just developed over the past decades. Their rejection for sodium chloride foats between 20 and 80% and their molecular weight cut-offs for dissolved organic solutes from 200 up to 2000 Da [1-2]. For water treatment with chitosan, a composite nanofltration membrane with a microporous substrate providing the mechanical strength and a selective layer coating of a different material is an appropriate solution. Chitosan, the deacetylated derivative of chitin, is the second most abundant polysaccharide found on earth next to cellulose. As a natural renewable resource, chitosan has a number of unique properties such as antimicrobial activity, non-toxicity and biodegradability [3, 4]. The amino (–NH2) and/or hydroxy (–OH) groups on chitosan chains serve as coordination sites and this is the reason why chitosan is known as a suitable sorbent for heavy metal ions. Additionally, its mentionable flm forming characteristics are worthy [5]. As chitosan membranes prepared by evaporation and immersion-precipitation were dense and had low solidity respectively, they were not suitable for continuous processes [6-7]. Here,