Fabrication of Al2O3/PSf nanocomposite membranes: efficiency comparison of coating and blending methods in modification of filtration performance

Al2O3 nanoparticles were added to polysulfone (PSf) ultrafiltration membrane through the two methods of surface deposition and structure entrapment, to study the membrane performance in filtration of dye solutions. Alumina nanoparticles were synthesized through coprecipitation method and were added to casting solution containing PSf as a main polymer (17wt.%), N-methyl-2-pyrrolidone as a solvent (75wt.%), and polyethylene glycol with molecular weight of 400 as a pore former (8wt.%). In addition, a deposition of nanoparticles onto the surface of the pre-prepared PSf membrane was formed by using photo-polymerization method. Water flux and rejection of disperse dye solution were studied afterwards. According to the obtained results, the synthesized nanocomposite membranes showed less flux decline but higher dye rejection in comparison with neat polymeric membranes. Results also showed higher dye rejection for membrane modified by entrapment method, while membrane modified by surface deposition method had higher dye flux. Fourier transform infrared spectrum analysis confirmed the presence of alumina nanoparticles in the structure and on the surface of the membrane. According to X-ray diffraction analysis results, the size of synthesized alumina nanoparticles were 16.61nm and it reached 58.3nm after being placed in the polymeric structure.