ORIGINAL PAPER Fabrication of thin film-PEI nanofiltration membrane with promoted separation performances: Cr, Pb and Cu ions removal from water S. Bandehali 1 & F. Parvizian 1 & A. R. Moghadassi 1 & S. M. Hosseini 1 & J. N. Shen 2 Received: 30 September 2019 /Accepted: 27 February 2020 # The Polymer Society, Taipei 2020 Abstract In this study, L-cysteine functionalized POSS nanoparticles were synthesized. The synthesized nanoparticles and methyl- methacrylate were applied to fabrication of polyether-imide-thin film nanocomposite nanofiltration membrane. The ratio of (MMA: NPs) changed to obtain efficient separation performances and good antifouling properties. Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM) analysis were used in membranes characterization. Pure water flux, Na 2 SO 4 , CrSO 4 , Pb(NO 3 ) 2 and Cu(NO 3 ) 2 rejection, membrane porosity, mean pore size of membrane and water contact angle were studies. Pure water flux measured 14.3 (L/m 2 .h) for neat membrane whereas that was 11–70.6 for thin-film membranes. Surface hydrophilicity enhanced and roughness, pore size and porosity decreased by increase of MMA:NPs ratio. The highest Na 2 SO 4 , CrSO 4 , Pb (NO 3 ) 2 and Cu(NO 3 ) 2 rejection observed 84%, 81%, 83% and 79%, at 0.03 wt.% of MMA:NPs ratio. FRR% measured ~95% at 0.03 wt.% of MMA:NPs ratio whereas it was ~29 for neat membrane. Keywords Nanofiltration membrane . Thin-film nanocomposite . Methyl methacrylate . L-cysteine functionalized POSS nanoparticles . Improved separation performance Introduction Nanofiltration (NF) membranes as press-driven membranes with molecular weight cut-off in the range of 200–1000 Da have been extensively studies for different salts and heavy metals separation during the last two decades. Currently, most NF membranes have been prepared through thin film compos- ite membranes (TFCs) as a production technique of membrane by interfacial polymerization [1–4]. Polyether-imide (PEI) has been extensively applied to membrane preparation especially in gas separation because of high mechanical and thermal stability [5–7]. Moreover, PEI shows good potential for formation of film with good chemical resistance in the wide range of pH. But PEI is hydrophobic that limits its application in the nanofiltration membranes due to low water permeability, reduce fouling resistance and decrease life time during the process. Since one of the major challenges and issues in membrane separa- tion is fouling. The different contaminants such as organ- isms, colloids and organics in the feed solutions adsorb on the membrane surface and diffuse onto the porosities or de- posit on the surface of membrane. The membrane fouling would effect on the membrane performance. Moreover, the biofouling and the formation of biopolymers or biofilm on the membrane surface is another problem that occurs in the wastewater treatment. The fouling phenomena on the mem- brane surface increase the need to repeated cleaning and maintenance processes that leads to increase cost for appli- cation of membrane technology in the wastewater treatment [8–11]. Thus, the fouling control is one of the major chal- lenges in the filtration membranes. Improvement of mem- brane hydrophilicity and increasing thickness of top layer on the membrane surface are the best methods for reducing fouling. * F. Parvizian f-parvizian@araku.ac.ir * S. M. Hosseini s-hosseini@araku.ac.ir 1 Department of Chemical Engineering, Faculty of Engineering, Arak University, Arak 38156-8-8349, Iran 2 Center for Membrane Separation and Water Science & Technology, Ocean College, Zhejiang University of Technology, Hangzhou 310014, China Journal of Polymer Research (2020) 27:94 https://doi.org/10.1007/s10965-020-02056-x