基于SDS临界胶束浓度调控BiOBr合成及其光催化降解头孢拉定研究

Regulation of BiOBr Synthesis Based on SDS Critical Micelle Concentration and the Photocatalytic Degradation of Cefradine

以十二烷基硫酸钠(sodium dodecyl sulfate,SDS)为模板剂,采用沉淀法制备了不同胶束浓度条件下的BiOBr光催化剂(SBr-1、SBr-2、SBr-3、SBr-4).通过XRD、SEM、BET表征BiOBr晶体结构、形貌和比表面积,结果表明在SDS为临界胶束浓度(8.0×10^(-3)mol/L)时制备的SBr-2具有较好的结晶度、特殊的形貌和最大的比表面积;运用UV-vis DRS吸收光谱、PL光谱、EIS电化学抗阻谱等表征BiOBr光电特性,结果证明SBr-2具有良好的可见光吸收能力和电子空穴分离效率.在可见光照射(λ≥420 nm)下,选用头孢拉定(cefradine,CFD)为目标污染物研究光催化活性,结果表明SBr-2具有最好的光催化活性,150 min内降解率达到98%.此外,通过自由基捕获试验,发现该光催化过程超氧自由基和空穴为主要活性物种.本研究为表面活性剂调控改善BiOBr结构、形貌和晶相提升其光催化活性提供了理论参考.

BiOBr photocatalysts(SBr-1,SBr-2,SBr-3,SBr-4)with Sodium Dodecyl Sulfate(SDS)as the template were prepared by precipitation method under different micellar concentrations.The crystal structure,morphology and specific surface area of BiOBr were characterized by XRD,SEM and BET.The results showed that SBr-2 prepared at the critical micelle concentration of SDS(8.0×10^(-3)mol/L)had better crystallinity,special morphology and maximum specific surface area.The photoelectric properties of BiOBr were characterized by UV-vis DRS absorption spectrum,PL spectrum and EIS electrochemical resistance spectrum.The results show that SBr-2 has good visible light absorption capacity and electron hole separation efficiency.Under visible light irradiation(λ≥420 nm),Cefradine(CFD)was selected as the target pollutant to study the photocatalytic activity.The results showed that SBr-2 had the best photocatalytic activity,and the degradation rate reached 98%within 150 min.In addition,it was found that superoxide free radicals and holes were the main active species in the photocatalytic process.This study provides a theoretical reference for improving the structure,morphology and crystal phase of BiOBr by surfactant regulation to enhance its photocatalytic activity.