CuBi_(2)O_(4)/Bi_(2)WO_(6)Z型异质结用于光电类芬顿体系下高效降解环丙沙星

CuBi_(2)O_(4)/Bi_(2)WO_(6)Z-type Heterostructures for Effective Removal Ciprofloxacin in Photo-electro-Fenton-like System

针对目前水环境中抗生素污染严重的问题,使用简单的溶剂热法制备了CuBi_(2)O_(4)/Bi_(2)WO_(6)(CBWO)Z型异质结催化剂.扫描电子显微镜分析结果表明,其结构为棒状和纳米片状.能量色散元素图谱显示,Cu,W,Bi和O元素均匀分散在CBWO-60中;使用X射线衍射和傅里叶变换红外光谱探究了催化剂的晶体结构和化学键、官能团组成;BET表征结果证明,CBWO-60具有较高的比表面积.X射线光电子能谱(XPS)证明Cu^(+)和Cu^(2+)共存,促进了芬顿(Fenton)反应的循环进行,XPS结合能的位移证明了异质结中CuBi_(2)O_(4)和Bi_(2)WO_(6)之间具有强的电子相互作用,而不是物理混合;使用紫外⁃可见漫反射光谱和价带-X射线光电子能谱分析了异质结的能带结构;利用光致发射光谱、电化学阻抗谱和瞬态光电流响应谱探究了催化剂的电荷转移情况.在该系列催化剂中,CBWO-60在光电类芬顿(PEF-like)体系中对环丙沙星(CIP)的降解效率最高,90 min时,降解效率为98.0%.同时,溶液初始pH在2~6范围时,体系始终能够维持有效的CIP去除效率,与传统芬顿体系相比,该体系的pH应用范围得到了有效拓宽.在PEF-like体系中,CBWO-60对喹诺酮类、磺胺类和四环素类抗生素均表现出较强的降解能力,充分证明了CBWO-60的普适性.CBWO-60在连续5次循环实验后,对CIP仍保持87.8%的降解率,并且反应后催化剂的晶体结构没有发生改变.根据高效液相色谱⁃质谱的结果,提出了CIP降解的5种可能途径.

In response to the serious problem of antibiotic pollution in the current water environment,herein,a CuBi_(2O)4/Bi_(2)WO_(6)(CBWO)Z-type heterojunction photoelectric catalyst was synthesized by a simple solvothermal method.The morphology and structure were obtained through SEM,which showed that the structure of the CBWO-60 was cuboid rod-like morphology and nanosheet.The EDS elemental mapping images displayed that Cu,W,Bi and O elements were evenly dispersed in CBWO-60.The crystalline phases and molecular structures of the catalyst were determined by XRD and FTIR.These results firmly confirmed that the successful synthesis of the composite.The large specific surface area of CBWO-60 was investigated via BET.XPS analysis proved that the Cu^(+)and Cu^(2+)coexisted,which promoted the cycling of Fenton reaction.Moreover,the displacement of binding energy well verified the strong electronic interaction rather than a physical contact between CuBi_(2)O_(4) and Bi_(2)WO_(6) in the heterojunction.The band structure of the heterojunction was proved by UV-Vis DRS and VB-XPS analysis.The interface charge transfer situation of the heterojunction was investigated by PL,EIS,and transient photocurrent response spectra.In a series of catalysts,CBWO-60 has the highest degradation efficiency for Ciprofloxacin(CIP)in the photo-electro-Fenton-like(PEF-like)system,with a degradation efficiency of 98.0%at 90 min.At the same time,when the initial pH of the solution was in the range of 2—6,the system could always maintain effective CIP removal efficiency.The pH range of this system was broadened to some extent compared to the conventional Fenton method.In the PEF-like system,CBWO-60 showed high catalytic activity to quinolone,sulfonamides and tetracycline antibiotics,which proved the universality of CBWO-60.Finally,the degradation efficiency of CIP still maintained 87.8%after five cycles of experiments,and the crystal structure of CBWO-60 remained unchanged after the reaction.Based on the results of HPLC-MS,five possible pathways for CIP degradation were proposed.This study provided a new idea for the purification and treatment of antibiotic pollution in the water environment.