College of Environmental Science and Engineering/Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tong Yan Road 38, Tianjin, 300350, China.
College of Environmental Science and Engineering/Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tong Yan Road 38, Tianjin, 300350, China.
Water Res. 2019 Sep 1;160:197-205. doi: 10.1016/j.watres.2019.05.073. Epub 2019 May 23.
With the widespread use of oxytetracycline (OTC), residual OTCs have been detected in natural surface waters, as well as in water and wastewater treatment systems. Semiconductor photocatalysis has been proven to be a green and high-performing method for the removal of organic contaminants. However, most photocatalysts are only effective when irradiated by UV light. This study explores the efficiency of a new semiconductor photocatalysis method for OTC removal under solar and visible light. To expand the spectral range from the UV to the visible region, a facile prepared ball-like TiO at graphene oxide (TiO@GO) composite, a TiO-associated catalyst, was synthesized. Chemical characterization indicated that the TiO@GO has the features of both TiO and GO, with the regular TiO fiber balls cladded by GO nanosheets. The photocatalytic activity of TiO@GO composites under solar and visible light was evaluated in terms of OTC degradation. Values of 100% and 90% OTC removal efficiencies were achieved with TiO@GO at 6 mg/L under solar and visible light irradiation, respectively. The band structure of TiO@GO expanded the spectral range to full light wavelengths, facilitating formation of a light-induced electron hole (h), which was identified in this study as the major cause of OTC degradation. The pH and TSS levels (>100 mg/L) were found to have high and low impacts, respectively, on the removal efficiency of OTC, while natural organic matter (NOM) was found to have an insignificant impact. Furthermore, the degradation of OTC with catalysis by TiO@GO was verified using two real water samples, and averages of 90% and 75% OTC removal efficiencies were achieved under solar and visible light respectively. The results indicate that the synthesized TiO@GO composites can provide an effective way of removing toxic organic compounds, including OTC, from the water system.
由于土霉素（OTC）的广泛使用，自然地表水以及水和废水处理系统中都检测到了残留的 OTC。半导体光催化已被证明是去除有机污染物的一种绿色、高性能方法。然而，大多数光催化剂只有在受到紫外光照射时才有效。本研究探讨了一种新的半导体光催化方法在太阳光和可见光下去除 OTC 的效率。为了将光谱范围从紫外扩展到可见区域，制备了一种简便的 TiO@GO 复合半导体光催化剂，该催化剂是一种与 TiO 相关的催化剂。化学特性表明，TiO@GO 具有 TiO 和 GO 的特性，其规则的 TiO 纤维球被 GO 纳米片包裹。通过 OTC 降解评价了 TiO@GO 复合材料在太阳光和可见光下的光催化活性。在太阳光和可见光照射下，TiO@GO 在 6mg/L 时分别达到了 100%和 90%的 OTC 去除效率。TiO@GO 的能带结构将光谱范围扩展到全光波长，有利于形成光致电子空穴（h），本研究认为这是 OTC 降解的主要原因。pH 值和 TSS 水平（>100mg/L）分别对 OTC 的去除效率有高和低的影响，而天然有机物（NOM）的影响可以忽略不计。此外，使用两种实际水样验证了 TiO@GO 催化下的 OTC 降解，在太阳光和可见光下分别达到了 90%和 75%的 OTC 去除效率平均值。结果表明，合成的 TiO@GO 复合材料可以为去除水系统中的有毒有机化合物（包括 OTC）提供一种有效途径。
