High permeability poly(vinylidene fluoride) ultrafiltration membrane doped with polydopamine modified TiO2 nanoparticles

• 作者: Qi Zhang Weixing Li Zhaoliang Cui
• 来源期刊: 中国化学工程学报（英文版）
• 年，卷（期）: 2020,（12）
• 所属期刊栏目: Materials and Product Engineering
• 页码范围: 3152-3158
• 页数: 7页
• 语种: 英文

摘要

In order to improve the water permeability of poly(vinylidene fluoride) (PVDF) ultrafiltration (UF) membranes with low molecular weight cut-off (MWCO), polydopamine (PDA) was employed in the membrane preparation process. Owing to its merits of material-independent adhesion, PDA was coated on inorganic particles or added in coagulation bath to tailor the final membrane structure and property. The introduction of PDA broke through the permeability/selectivity trade-off of the PVDF membrane. By adding the PDA coated titanium dioxide (PDA/TiO2) nanoparticles, water flux increased by 287％ while MWCO kept similar with the pristine PVDF membrane. Ther-modynamics and Kinetics of the PVDF/additives/non-solvent were analyzed and shown that nanoparticles re-duced the thermodynamic stability and increased the phase separation speed, and the speed can be adjusted using different nanoparticles. Additionally, X-ray diffraction (XRD) test indicated that PVDF crystalline form changed from α phase to β phase after adding different nanoparticles. Permeability/selectivity trade-off was bro-ken through by DA addition in coagulation bath. Compared with the original PVDF membrane, when the DA con-centration of the coagulation bath was 2.0 g·L-1, water flux increased by 312％, and MWCO of the PVDF membrane ranged in 10,000 to 20,000 Da as well as contact angle decreased from 81.4° to 45°.