新型光催化材料制备及其PVDF膜自清洁改性

A Novel (H)g-C_3N_4/Ag_3PO_4/TiO_2 Photocatalysis Composite Modified PVDF Membrane and Its Evaluation on Self-cleaning Properties

膜污染问题制约着膜分离技术在水处理领域的应用,为解决此问题,文章提出将光催化与膜分离技术联用,制备出紫外-可见光响应三元光催化材料(H)g-C_3N_4/Ag_3PO_4/TiO_2,将其用于聚偏氟乙烯(PVDF)膜亲水性及自清洁改性。通过X-射线衍射、扫描电子显微镜、紫外可见吸收光谱分析、光致发光光谱分析及光催化降解实验研究光催化材料的物化性能。通过接触角测量及通量恢复率实验表征改性复合膜的抗污染性能。结果显示:由于光生电子和空穴的有效分离,(H)g-C_3N_4/Ag_3PO_4/TiO_2展示了良好的光催化活性和稳定性;与未改性膜相比,掺杂0.5%的(H)g-C_3N_4/Ag_3PO_4/TiO_2的PVDF复合膜初始接触角由78.3°降低到60.7°,膜通量恢复率由45%升高到80.65%。改性复合膜材料具有良好的自清洁性能。

Extensive applications of membrane technology suffers membrane fouling problem which limits its further development. Coupling membrane separation with photocatalysis provides a new idea for mitigating effect of membrane fouling. In this study, a （H）g-C3NdAg3POdTiO2 ternary photocatalyst is fabricated with enhanced photocatalytic activity. Then the material is used to modify polyvinylidene fluoride （PVDF） membrane with improved hydrophilicity and self-cleaning properties via method of nonsolvent-induced phase inversion. The physical-chemical properties of the material are characterized by XRD, SEM, UV-vis absorption spectra and PL spectra. The results show that （H）g-C3NdAg3POdTiO2 exhibit high photocatalytic activity which attribute to the robust separation of photo-excited electrons （e-） and holes （h＋） caused by formation of more ternary heterojunctions. The self-cleaning property of modified PVDF is evaluated by measuring the water contact an- gle and flux recovery rate. The initial contact angle of the PVDF membrane modified by 0.5% （H）g-CaNa/Ag3PO4/TiO2 （PVDF-0.5）, in contrast to PVDF-0, decreases from 78.3° to 60.7°. Moreover, the flux recovery rate of PVDF-0.5 reached 80.65% compared to 45% for PVDF-0 after continuous operation for 1 h, which reflects excellent self-cleaning properties for PVDF-0.5 under natural light irradiation. The modified membrane material displays good self-cleaning property.