Fe(Ⅱ)活化亚硫酸盐降解卡马西平的动力学及机制研究
2021-09-13李阳关小红董红钰
李阳 关小红 董红钰



摘 要:高级氧化技术是去除水中新型有机污染物的重要方法之一。研究Fe(Ⅱ)活化亚硫酸盐(Fe(Ⅱ)/亚硫酸盐)体系降解卡马西平(CBZ)的动力学及体系中活性氧化物种对CBZ降解的贡献。结果表明:当亚硫酸盐浓度由0.20 mmol/L增加至0.50 mmol/L时,反应20 min时Fe(Ⅱ)亚硫酸盐体系对CBZ的去除率不断增加,而进一步增加亚硫酸盐浓度时,卡马西平的去除率不再进一步增加。当反应初始pH值为3.0~7.0时,Fe(Ⅱ)/亚硫酸盐体系均可降解CBZ,在初始pH值为5.0时,此体系对CBZ的去除率最高,反应平衡时CBZ的去除率达87.3%。此外,铁盐中SO2-4和Cl-对Fe(Ⅱ)/亚硫酸盐体系降解CBZ基本无影响。综合电子顺磁共振检测及淬灭剂实验的结果可知,Fe(Ⅱ)/亚硫酸盐体系中所產生的活性氧化物种包括硫酸根自由基(SO-4·)、羟基自由基(HO·)和过一硫酸根自由基(SO-5·),它们均对卡马西平的降解起贡献作用,其中SO-4·和HO·起主要贡献作用。
关键词:亚铁;亚硫酸盐;硫酸根自由基;羟基自由基;新型有机污染物;卡马西平
中图分类号:X522;X592 文献标志码:A 文章编号:2096-6717(2021)06-0165-07
Abstract: Advanced oxidation processes (AOPs) are one of the important methods to remove emerging organic contaminants in water. In this study, we investigated the degradation kinetics of carbamazepine (CBZ) during the activation of sulfite by Fe(Ⅱ) (Fe(Ⅱ)/sulfite system) and the contribution of reactive oxidative species to the degradation of CBZ in this process. The research results showed that the removal of CBZ at 20 min in the Fe(Ⅱ)/sulfite system increased with the concentration of sulfite increasing from 0.20 mmol/L to 0.50 mmol/L, while the removal of carbamazepine did not further increase with further increasing the sulfite concentration. CBZ could be degraded in the Fe(Ⅱ)/sulfite system over the initial pH (pHini) range of 3.0~7.0. The removal of CBZ at pHini 5.0 was the highest and was 87.3% at equilibrium. In addition, SO2-4 and Cl- in the Fe(Ⅱ) salt had no influence on the degradation of CBZ in the Fe(Ⅱ)/sulfite system. The results of electron paramagnetic resonance and quenching experiments showed that the reactive oxidative species in the Fe(Ⅱ)/sulfite system included sulfate radical (SO-4·), hydroxyl radical (HO·) and peroxymonosulfate radical (SO-5·), contributing to the degradation of CBZ,and the degradation of CBZ was mainly contributed by SO-4· and HO·.
Keywords: ferrous; sulfite; sulfate radical; hydroxyl radical; emerging organic contaminants; carbamazepine
近年来,随着经济社会的快速发展,人工合成有机化合物的种类每年以惊人的速度增加,在这些有机化合物的生产、运输、使用及废弃过程中,人们的不当行为造成它们进入自然水体,导致大量的水源水受到新型有机污染物(Emerging organic contaminants,EOCs)的污染[1-2]。其中,卡马西平(carbamazepine,CBZ)是一种典型的抗癫痫药物,是水环境中最常见的EOCs之一[3-5]。全世界CBZ的年平均消耗量巨大,高达1 014 t[6],所消耗的CBZ大部分被排放到天然水体中。这些EOCs在水中的浓度低、种类多、性质复杂,传统的污水处理工艺及常规饮用水处理工艺难以将其去除。……
