负载型光催化膜特征及氟伐他汀降解性能分析

为克服传统悬浮型光催化技术因催化剂分离困难而导致的水体二次污染问题,通过悬浮过滤方式将ZnIn_2S_4负载在超滤膜表面得到光催化膜.利用扫描电镜(SEM)、紫外-可见漫反射光谱分析(UV-Vis)、X射线光电子能谱分析(XPS)、X射线衍射图谱分析(XRD)对其进行表征并分析其超滤性能.以氟伐他汀为目标污染物,采用功率500 W,光强230 W/m~2的长弧氙灯为光源,考察不同负载量光催化膜在光照条件下对氟伐他汀的降解率.结果表明,随着ZnIn_2S_4负载量增加,光催化膜对紫外光和可见光的响应逐渐增强,表面Zn、In、S元素特征峰响应逐渐增强,ZnIn_2S_4六方相型特征衍射峰逐渐增大,膜表面形成了均匀的光催化功能层,膜面亲水性增强,纯水通量衰减得到缓解,对氟伐他汀的降解率明显提高.但是过量ZnIn_2S_4会在膜面发生堆叠团聚,降低催化剂利用率,进而影响催化效率.负载量为0.2 g的光催化膜表面ZnIn_2S_4光催化层均匀,能有效利用光源能量,催化活性高,节省物料,在光照条件下对氟伐他汀的降解率可高达94.75%,长期运行下具有良好的光催化稳定性.

Characteristics of photocatalytic membrane loaded with ZnIn2S4 and its degradation performance of fluvastatin

To overcome the problem caused by the separation photocatalysts from system in the traditional photocatalytic technology, the photocatalytic membrane was prepared by filtrating suspended ZnIn₂S₄ on the surface of ultrafiltration membrane and was characterized by SEM, UV-Vis, XPS, XRD, and the ultrafiltration performance was also analyzed. The degradation rate of fluvastatin by photocatalytic membranes was investigated under a 500 W xenon lamp with intensity of 230 W/m². With the increase of the photocatalyst loading, the absorbance of photocatalytic membrane in ultraviolet and visible light region increased, the characteristic peak response of Zn, In and S elements increased, the diffraction peak of ZnIn₂S₄ with hexagonal phase increased and the hydrophilicity increased, which indicated that formation of photocatalytic coating layer on the surface. The degradation rate of fluvastatin was also enhanced by formation of photocatalytic coating layer. However, agglomeration of excess ZnIn₂S₄ on the surface of the membrane leaded to reducing the utilization rate of the photocatalyst and affeced the photocatalytic efficiency. The photocatalytic coating layer of photocatalytic membrane with 0.2 g ZnIn₂S₄ could be effectively excited by xenon lamp and the degradation rate of fluvastatin was 94.75%.