الفهرس | Only 14 pages are availabe for public view |
Abstract -All factors which could effect on preparation of PSf membrane by wet phase inversion were studied by evaluation under VEDCMD unit and experimental results illustrated that DMF was suitable solvent than DMAc to synthetize membranes of MD from PSf, increase in concentration of PSf in casting solution inversely proportion with MD Flux, 15 % w/v was the best concentration, increase in thickness of PSf membrane led to reduction in MD flux, increase in solvent evaporation time before coagulation step decline MD flux, temperature of coagulation increase led to decrease of MD flux,(25 oC) was selected as best coagulation temperature and presence different concentration of solvent in coagulation bath effect slightly on MD flux also presence of LiCl with different concentration in coagulation bath led to enhancement of MD flux. 2-Operation parameters which could effect on MD flux were studied by using membrane of PSf (15% w/v) where experimental results illustrated the increase of feed temperature increase flux of MD, on contrary increase of permeate temperature decrease MD flux this according to thermodynamic effect, also increase in feed flow rate increase MD flux as reducing of temperature polarization with fast flow rate, increase in feed concentration decrease slightly MD flux so MD suitable desalination process for high water salinity, also decrease of pores pressure in permeate side by vacuum enhance MD flux and this pressure must be less than membrane LEP. Durability of membrane was investigated as function with MD flux and permeate EC where PSf membrane gave good stability and salt reject through operation time period ,it is found that change of feed salt type effect on MD flux according to Rout’s law as we found MD flux of NaCl > MgSO4 >Na2SO4 at same operation conditions. 3-All modified PSf membrane with different nano-materials and different concentrations were studied where PSf/MWCNTs membranes MD Conclusion and recommendations [135] flux increase with MWCNTs increase until (1%) then flux started in reduction and this was attributed to tubular nature of MWCNTs , its hydrophobicity , its effect on morphology of PSf membrane and all this effect on mass transfer mechanism of PSf membrane .Also we found that (0.5%) was the best concentration was added to PSf/SiO2 membrane when we used silica mesoporous with different concentration and (0.75%) was optimal TiO2 concentration was added to PSf/TiO2 also (0.5 %) was the best ZnO concentration could give high MD flux all this inorganic nonmaterial effect by significantly on PSf membrane morphology as illustrated in SEM images and other characterization analysis. Dispersion sonication time of different nanomaterials was studied as function with MD flux where sonication time of MWCNTs in dispersion medium of DMF had clear effect on MD flux productivity also in case of TiO2 and ZnO sonication increasing enhanced MD flux of PSf. Moreover, comparison study was done between neat PSf membrane and optimal modified membranes. |