چكيده به لاتين
Abstract
Nanofiltration (NF) is a type of membrane filtration with properties between ultrafiltration (UF) and reverse osmosis (RO). An important issue facing NF membranes is the trade-off between rejection and permeability. This research tries to fabricate membranes with good performance when it is used to address the selectivity/permeability trade-off challenge. This research consists of two parts: first fabricating neat membranes and optimizing potentially important synthesis parameters; next using amine functionalized multiwalled carbon nanotube (f-MWCNT) in membranes support to investigate its effect on the membranes performance. The experimental design was performed using central composite design (CCD), based on the response surface methodology (RSM) to obtain optimum synthesis parameters of the UF support membrane as well as the NF top layer. Based on the optimization results parameters including polyethersulfone (PES) concentration in support layer, piperazine (PIP), trimesoyl chloride (TMC) concentration in top layer and reaction time were adjusted to 14 wt%, 1.5 w/v%, 0.2 w/v%, and 45 s, respectively. An additional membrane was prepared based on the optimum conditions of the preparation process. The permeation and rejection tests were performed; results were in good agreement with the values predicted by the model. Afterward, f-MWCNTs / PES hybrid membranes were fabricated and characterized by FTIR, ATR-FTIR, AFM, and SEM analysis. In the best nanoparticles loading ratio of 0.15 wt%, the fabricated membrane exhibited pure water flux of 9.84 LMH/bar which showed 20 % improvement compared with the neat NF membranes. Concerning the results of contact angle and porosity mesurements of the neat membranes and nanocomposite membranes, adding nanoparticles result in contact angle reduction from 74/84° to 57/99°, as well as increasing hydrophilicity and porosity from 70 % to 78 %.
