(191s) Fabrication and Characterization of Novel Cellulose Acetate Hollow Fiber Nanoporous Membranes Prepared Via Thermally Induced Phase Separation

Pang, B., Sinopec Research Institute of Petroleum Processing
Mao, J., Sinopec Research Institute of Petroleum Processing
Wang, X., Tsinghua University
Cellulose acetate (CA) is a kind of environment-friendly and biodegradable material and CA separation membrane has been widely used in the fields of food processing, pharmaceutical engineering, medicine, etc.. Hydrophilic modified cellulose acetate (CA) hollow fiber nanoporous membrane was firstly fabricated via thermally induced phase separation (TIPS) method. The hydrophilic additive was added into the dope solution. The effects of additive on membrane morphologies, hydrophilicity, permselectivity of CA membrane were investigated systematically. With the increase of additive content, the fabricated membrane had the denser cross-section pore structure and the thicker surface layer. The morphological change was beneficial to the membrane ductibility, corresponding to the increase of elongation from 20.0 % to 74.8 %. The additive played a critical role in the improvement of membrane hydrophilicity. The initial contact angle sharply decreased from 79° of CHM25 membrane to 53° of CPHM25-4 membrane. The additive molecules presented excellent twine with CA molecules which facilitated the improvement of membrane performance stability. The preferred CPHM25-2 membrane had the ultrafiltration membrane characteristics with high rejections for different neutral solutes. The molecular weight cut-off (MWCO) was about 13000 Da and the pure water flux increased 8 times compared with CHM25 membrane. Furthermore, heat treatment were adopted to compact the surface pore size in order to realize the membrane separation performance transition from ultrafiltration to nanofiltration. As for CPHM25-2-80-50 membrane, the rejections of Na2SO4 and NaCl solution could reach 89.6 % and 29.0 %. It is promising that the novel hydrophilic modified CA hollow fiber nanoporous membrane has broad application prospects in the fields of food processing, chlor-alkali industry, wastewater treatment, etc..