زهرا شعباني ششكل

A novel polyvinyl chloride (PVC) membrane was synthesized by phase inversion method. When the dope polymer solution concentration decreased from 17 to 10 wt%, water flux increased from 4.15 to 15.95 L/m2.h and reverse salt flux (RSF) from 0.87 to 3.50 g/m2.h, using DI water as feed solution (FS) and 1 M NaCl as draw solution (DS). Then, the 10 wt% PVC substrate was selected for modification and it was modified by dopamine (DA) solution for 1 and 3 h. Compared to the pristine membrane, the 1 h polydopamine (PDA) modified membrane displayed a higher water flux (18.90 L/m2.h) and lower RSF (3.35 g/m2.h). In the next step, DA was mixed into m-phenylenediamine (MPD) as an aqueous solution followed by interfacial polymerization (IP) reaction with trimesoyl chloride (TMC) on a fabricated PVC substrate. The simultaneous effects of the DA concentration and the co-deposition time on the membrane morphology and FO properties were systematically investigated to explore the optimum condition. After eva‎luating the as-prepared membranes, the membranes with the DA concentration of 0.1 g/L and 120 min co-deposition time of PDA and MPD showed a high water flux (24.40 L/m2.h) and acceptable reverse salt flux (3.86 g/m2.h). Then, various UiO-66-NH2 were synthesized with manipulating the dopamine (DA) concentration and the best one was selected based on their FO performance (MOF@PDA(0.25)). The effects of different loading of the selected NPs on the FO performance were eva‎luated. In comparison with the conventional thin film composite (TFC) membranes, incorporation of 0.02 wt% MOF@PDA(0.25) led to enhanced water flux of the TFN membrane (29.73 L/m2.h) due to the establishment of extra water channels and the improved hydrophilicity. By comparing the FO selectivity of the TFN membranes with UiO66-NH2 (0.21 g/L) and MOF@PDA(0.25) (0.16 g/L), it can be concluded that the presence of PDA in both NPs and the aqueous phase during fabrication improves the compatibility between NPs and PA layer to enhance water flux without sacrificing selectivity. Compared with the pristine membrane, all modified membranes revealed brilliant performance in the seawater desalination and exhibited excellent rejection of heavy metal ions (Cu2+ and Pb2+). Finally, for understanding whether the experimental data can be supported by a theoretical model, the obtained experimental results were compared with a computational fluid dynamics (CFD) model and the results demonstrated acceptable agreement with each other. On the other hand, the results showed that membrane length and flow velocity are effective in membrane performance. The effect of membrane length when the velocity is high can be ignored. When the velocity is low the effect of membrane length can not be neglected. The velocity on the draw channel and the feed channel is more important to increase water flux in FO and PRO mode, respectively.

پلي وينيل كلرايد , غشاي مركب لايه نازك , اسمز مستقيم , پلي دوپامين , چارچوب هاي فلز-آلي

Zahra Shabani

Dr. Toraj Mohammadi, Dr. Norollah Kasiri