BiOBr的可控制备及对废水中卡马西平的有效降解

以Bi(NO₃)₃·5H₂O为原料, 乙醇为介质, KBr和/或十六烷基三甲基溴化铵(CTAB)为溴源, 采用溶剂热法合成了不同结构和性能的BiOBr微纳米材料, 通过 X射线衍射仪(XRD)、 扫描电子显微镜(SEM)、 红外光谱仪(FTIR)、 紫外-可见漫反射光谱(UV-Vis DRS)及比表面积和孔隙度分析仪对产物进行了表征. 结果表明, 溴源(KBr, CTAB)对BiOBr的结晶特性和形貌有重要影响, 其中采用双溴源且KBr与CTAB摩尔比为3∶7时制得的BiOBr(K∶C=3∶7)光催化剂在模拟太阳光下具有最优的光催化性能, 光照20 min后对废水中卡马西平的降解速率常数是以KBr为溴源制备的BiOBr(K)的4.10倍和以CTAB为溴源制备的BiOBr(C)的2.14倍. BiOBr(K∶C=3∶7)优异的光催化活性可归因于其高暴露的(110)晶面、 表面羟基、 疏松的片层状形貌及较大的比表面积和孔体积. 活性物种淬灭实验结果表明, BiOBr(K∶C=3∶7)的光催化活性主要源于光生空穴、 羟基自由基和电子.

Tunable Synthesis of BiOBr for Efficient Photocatalytic Degradation of Carbamazepine in Wastewater †

A series of BiOBr photocatalysts was prepared with different bromine sources using an ethanol mediated solvothermal method with Bi(NO₃)₃·5H₂O as precursor. The obtained samples were characterized by powder X-ray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform Infrared spectroscopy(FTIR), UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS) and N₂ adsorption-desorption analysis. The results showed that the crystallinity structure, morphology and specific surface were influenced by bromine source. The BiOBr(K∶C=3∶7) sample prepared with KBr and CTAB(molar ratio 3∶7) as bromine sources exhibited high photocatalytic efficiency towards the degradation of carbamazepine under simulated solar light irradiation. The photocatalytic reaction with BiOBr(K∶C=3∶7) as catalyst followed pseudo first-order kinetics model with a reaction rate constant over 4.10, and 2.14 times that with BiOBr(K) and BiOBr(C) as catalyst, respectively. The enhanced photocatalytic activities could be attributed to the highly exposed(110) facet, surface hydroxyl, loose-packed lamellar morphology, as well as large specific surface area and pore volume. Radicals trapping experiments showed that h ⁺, ·OH and e ^- were involved in the photocatalytic degradation of carbamazepine.