Synthesis of PVDF nanocomposite surface-modified membrane containing ZnO:Ca for dye removal from colored wastewaters in a fixed-bed photocatalytic-membrane reactor

In the present study, the process of synthesis of polymeric membranes based on polyvinylidene fluoride (PVDF) was investigated using different techniques of phase inversion and also the process of surface modification was carried out via chemical method with diethanolamine (DEA). Also, removal of Reactive Red 120 (RR120), Reactive Blue 19 (RB19), and Basic Violet 16 (BV16) from the synthetic effluent was evaluated in the dead-end membrane system. Results revealed that 20% w/w of polymer is suitable for production of a uniform film which is resistant against fluid pressure (2–4 bar). DEA optimal (%w/w) was determined about 20% to remove the fluorine atoms from the hydrocarbon chain in order to increase the hydrophilic properties of membrane. Furthermore, the nano-photocatalyst zinc oxide: calcium (ZnO:Ca) was synthesized by combustion method. The optimum value of ZnO:Ca nanoparticles to make a nanocomposite membrane (PVDF/ZnO:Ca) was 10% w/w. Findings showed that decolorization of RR120, RB19 and BV16 using membrane system was increased from 3.84%, 2.61% and 37.52% to 18.45%, 27.36% and 66.45%, respectively, within 2 h because of chemical modification and ZnO:Ca photocatalyst nanoparticles. In addition, the removal efficiencies of dyes in a fixed-bed photocatalytic-membrane reactor (FPMR) during 1 h were 65.10%, 75.95% and 65.04%, respectively. Finally, results indicated that FPMR has a high removal efficiency, compared with the other studied membrane systems.