PVA/TiO_2复合薄膜长期光催化过程中的耐用性评价

Reusability of PVA/TiO_2 Hybrid Films during Long-term Use in Photocatalytic Process

利用冷冻-解冻法制备了具有较高光催化活性的PVA/TiO_2复合薄膜,长期实验结果显示,冷冻-解冻次数对复合薄膜的光催化性能、材料耐用性以及纳米TiO_2包埋效率有明显影响。相比冷冻-解冻1次和3次的复合薄膜,冷冻-解冻5次得到的复合薄膜在长期实验中的光催化速率更高,包埋TiO_2的损失量更少,膜重量和膜厚度的变化也更小。结合电镜、红外、热重和结晶度数据阐明了纳米TiO_2在PVA载体上固定化作用,以及冷冻-解冻次数影响复合薄膜光催化性能和薄膜耐用性的原因。

This paper presented the preparation of PVA/TiO2 hybrid films of high photocatalytic activity by the freezing and thawing process. In addition, long-term tests were conducted which indicated that the number of freezing-thawing cycles notably affected photocatalytic activity, the durability of PVA/TiO2 hybrid films and the embedding efficiency of TiO2; the PVA/TiO2 hybrid films when being prepared with five freezing-thawing cycles, compared with one or three freezing-thawing cycles, had higher photocatalytic activity, fewer embedded TiO2 loss, as well as lower weight and thickness changes during the long-time photocatalysis process. The immobilization effect of nano-TiO2 in PVA matrix and the relationship among freezing-thawing cycles, photocatalytic activity and recyclability of the hybrid films were also illustrated and discussed with the analytic data of SEM, FI-IR and TGA.