Ag-BiOBr/WO3复合材料的制备及强化磺胺异噁唑去除性能

Preparation of Ag-BiOBr/WO3 composites and enhanced sulfisoxazole removal performance

抗生素类药物因其抗菌效果好在人畜医疗等领域得到广泛应用,但其在环境中难以自然分解,光催化氧化技术在降解持久型有机物方面有着光明的应用前景。然而,常规的光催化材料光谱吸收范围不够宽、光生载流子复合率过高,严重制约了催化材料的应用推广。因此,亟待研发更有效安全的去除技术。本文利用光沉积法将Ag单质负载于BiOBr/WO_(3)p-n型异质结材料表面,构建出新型Ag-BiOBr/WO_(3)材料,并将其用于光催化降解磺胺异噁唑。采用XRD、TEM、XPS、UV-vis DRS等技术对其进行表征表明,Ag的沉积拓展了材料的光响应范围,显著加快光生载流子的分离速度,从而提高了光催化性能。单质Ag含量为15wt%的材料为降解磺胺异噁唑效率最高的复合材料。当溶液中催化剂浓度为0.3 g/L,磺胺异噁唑浓度为5 mg/L,pH为7时,在60 min时光催化降解磺胺异噁唑的效率最高,可达98.1%,降解速率常数分别为BiOBr、WO_(3)和BiOBr/WO_(3)的28.79倍、36.37倍和7.59倍。经过5次循环实验后,15wt%Ag-BiOBr/WO_(3)复合材料仍具备较高的光催化活性,表明材料可循环回收利用,具备良好的稳定性。淬灭实验和电子自旋共振(ESR)结果表明,·O_(2)^(-)为15wt%Ag-BiOBr/WO_(3)体系中最活跃的自由基团,而^(1)O_(2)和h+发挥了次要作用。这为催化材料的制备和抗生素降解提供了理论基础。

Antibiotics have been widely used to treat human and animal diseases with good antibacterial effect.However,antibiotics are difficult to be degraded naturally in natural environment.The photocatalytic oxidation technology has bright application prospects in the degradation of persistent organic compounds.However,the spectral absorption range of conventional photocatalytic materials is not wide enough,and the recombination rate of photogenerated carriers is too high,which seriously restricts the application and promotion of catalytic materials.So,it is urgent to develop more effective and safe removal technologies.The photodeposition method was used to load Ag element on the surface of BiOBr/WO_(3)p-n type heterojunction material to construct a new type of AgBiOBr/WO_(3)material and apply to the photocatalytic degradation of sulfisoxazole.The samples were characterized by various techniques,such as XRD,TEM,XPS,UV-vis DRS et al.The result show that the deposition of Ag expands the photo-response range of the material,significantly accelerates the separation speed of photogenerated carriers,and thus improves the photocatalytic performance.The 15wt%Ag-BiOBr/WO_(3)with an Ag content of 15wt%is considered to be the most efficient composite material for the removal of sulfisoxazole.When the catalyst concentration is 0.3 g/L,the sulfisoxazole concentration is 5 mg/L,and the pH is 7,15wt%Ag-BiOBr/WO_(3)demonstrates the highest photocatalytic degradation efficiency of sulfisoxazole in 60 min,which reaches up to 98.1%.The degradation rate is 28.79,36.37 and 7.59 times higher than those of BiOBr,WO_(3)and BiOBr/WO_(3),respectively.After 5 cycles of experiments,the 15 wt%Ag-BiOBr/WO_(3)composite material still maintains high photocatalytic activity,indicating that the material can be recycled and reuses with good stability.The quenching experiments and electron spin resonance(ESR)shows that·O_(2)^(-)is the most active radical group in the BiOBr/WO_(3)system,while ^(1)O_(2)and h+played relatively minor roles.This provides a theoretical basis for the preparation of catalytic materials and the degradation of antibiotics.