SiO2纳米颗粒内嵌强化介孔TiO2单晶光催化降解盐酸四环素

吸附性能和光生载流子的分离效率是决定光催化降解抗生素的主要因素.为提高介孔TiO_2单晶(MSCs)的吸附性能和光生载流子的分离效率,在MSCs内部构建SiO_2纳米颗粒吸附结构.同时,利用表面光电压谱、氮气等温吸附-脱附、X射线衍射等研究其结构特性.最后,以盐酸四环素为抗生素代表,通过控制SiO_2纳米颗粒比表面积,考察SiO_2对复合材料吸附及光催化性能的影响.结果表明,SiO_2纳米颗粒与TiO_2单晶复合显著提高了材料的吸附性能,表面保护蚀刻进一步提升了材料的比表面积.实验条件下,高比表面积SiO_2-TiO_2单晶复合材料(KSiO_2@TiO_2)对盐酸四环素的平衡吸附量、降解效率、降解速率常数和矿化率分别达到了0.96 mg·g-1、90.2%、0.0079 min-1、54.4%,分别是MSCs的4.4、1.5、2.6和3.1倍.副产物分析表明,SiO_2复合介孔单晶材料更易将盐酸四环素降解为小分子物质.

SiO2 nanoparticles composited TiO2 single crystal for photocatalytic degradation of antibiotic

Adsorption capacity and charge separation efficiency are the main factors that determine the photocatalytic degradation efficiency of antibiotics. In order to improve the adsorption ability and photoactivity of mesoporous TiO₂ single crystals (MSCs), SiO₂ nanoparticles was induced into TiO₂ single crystal. The structural characteristics of the prepared materials were studied by surface photovoltage, nitrogen isothermal adsorption-desorption, and X-ray diffraction. The tetracycline hydrochloride was taken as the representative of antibiotics to investigate the photocatalytic activity of the prepared samples. The results showed that the combination of SiO₂ nanoparticles and TiO₂ single crystal significantly improved the adsorption amount of tetracycline hydrochloride and the charge separation efficiency of the composited MSCs. Under the experimental conditions, the equilibrium adsorption amount, degradation efficiency, degradation rate constant and mineralization rate of tetracycline hydrochloride for high surface area SiO₂-TiO₂ single crystal composites (KSiO₂@TiO₂) reached 0.96 mg·g^-1, 90.2%, 0.0079 min^-1, 54.4%, that were 4.4 times, 1.5 times, 2.6 times and 3.1 times of MSCs, respectively. Moreover, by-product analysis showed that KSiO₂@TiO₂ was more likely to degrade tetracycline hydrochloride into small molecules.