Abstract

The photocatalytic activity of bismuth oxychloride (BiOCl) toward sulfamethoxazole (SMX) elimination was investigated. BiOCl was synthesized according to a simple method using thiourea. Its physicochemical characteristics were determined by nitrogen physisorption, X-Ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy and transmission electron microscopy. Simulated solar irradiation and 1 g/L BiOCl, could effectively remove 0.5 mg/L SMX in less than 90 min. An increase in SMX concentration from 0.25 mg/L to 4 mg/L decreased the observed kinetic constant. Concerning the pH effect, it was found that under alkaline conditions SMX removal was slightly hindered. The water matrix's influence on SMX removal was explored, carrying out experiments in real water matrices, (bottled water (BW) and secondary effluent (WW)). Interestingly SMX removal was not practically altered in WW secondary effluent, but it was slightly hindered in BW bottled water. Experiments, performed in synthetic matrices, revealed that the presence of bicarbonates and chlorides slightly slowed down degradation kinetics, while humic acid enhanced SMX removal at concentrations up to 10 mg/L. Finally, an enhancement on SMX degradation was observed in the presence of persulfate. Quenching experiments of potential reactive species revealed that SMX degradation takes place mainly through reaction with hydroxyl radicals and photogenerated electrons.

摘要

研究了氯氧化铋 (BiOCl) 对磺胺甲恶唑 (SMX) 消除的光催化活性。BiOCl 是根据一种简单的方法使用硫脲合成的。通过氮物理吸附、X射线衍射、漫反射光谱、扫描电子显微镜和透射电子显微镜测定其理化特性。模拟太阳辐射和 1 g/L BiOCl，可在 90 分钟内有效去除 0.5 mg/L SMX。SMX 浓度从 0.25 mg/L 增加到 4 mg/L 会降低观察到的动力学常数。关于 pH 值的影响，发现在碱性条件下 SMX 去除受到轻微阻碍。研究了水基质对 SMX 去除的影响，在真实水基质（瓶装水 (BW) 和二次出水 (WW)）中进行了实验。有趣的是，在 WW 二级流出物中 SMX 的去除实际上没有改变，但在 BW 瓶装水中略有阻碍。在合成基质中进行的实验表明，碳酸氢盐和氯化物的存在略微减慢了降解动力学，而腐殖酸在浓度高达 10 mg/L 时增强了 SMX 的去除。最后，在过硫酸盐存在下观察到 SMX 降解增强。潜在活性物种的淬火实验表明，SMX 降解主要通过与羟基自由基和光生电子的反应发生。揭示碳酸氢盐和氯化物的存在略微减慢了降解动力学，而腐殖酸在浓度高达 10 mg/L 时增强了 SMX 的去除。最后，在过硫酸盐存在下观察到 SMX 降解增强。潜在活性物种的淬火实验表明，SMX 降解主要通过与羟基自由基和光生电子的反应发生。揭示碳酸氢盐和氯化物的存在略微减慢了降解动力学，而腐殖酸在浓度高达 10 mg/L 时增强了 SMX 的去除。最后，在过硫酸盐存在下观察到 SMX 降解增强。潜在活性物种的淬火实验表明，SMX 降解主要通过与羟基自由基和光生电子的反应发生。