研究报告
李苏奇,刘子正,王宇楠,李进军,吴峰.单线态氧氧化水中对氨基苯胂酸的研究[J].环境科学学报,2016,36(8):2852-2858
单线态氧氧化水中对氨基苯胂酸的研究
- The oxidation of p-arsanilic acid by singlet oxygen in water
- 基金项目：国家自然科学基金（No.51508423,21477090）；2014年武汉大学实验技术项目（No.WHU-2014-SYJS-04）
- 作者
- 单位
- 李苏奇
- 武汉大学资源与环境科学学院, 武汉 430079
- 刘子正
- 武汉大学土木建筑工程学院, 武汉 430072
- 王宇楠
- 武汉大学资源与环境科学学院, 武汉 430079
- 李进军
- 武汉大学资源与环境科学学院, 武汉 430079
- 吴峰
- 武汉大学资源与环境科学学院, 武汉 430079
- 摘要：阿散酸（p-ASA）作为一种有机砷饲料添加剂被广泛应用于养殖业以促进动物生长.因其几乎不被动物体吸收转化而易进入到养殖业环境中，其氧化降解则会向环境中释放无机砷而造成环境砷污染.以LED灯（λ=660 nm）为激发光源、亚甲基蓝（MB）为光敏剂，产生单线态氧（1O2），研究1O2对水中p-ASA的氧化降解形成无机砷的过程.同时考察体系初始pH、光照强度、光敏剂浓度等因素对反应的影响.结果表明，p-ASA经光敏反应而显著降解，并产生以As（V）为主的无机砷.p-ASA在偏碱性条件下降解显著；p-ASA降解率与光照强度呈正相关；p-ASA降解率随着光敏剂MB浓度增大先有明显提高，MB浓度大于3 mg·L-1后趋于稳定.选取糠醇（FFA）作为参考物，利用竞争动力学方法估算得出pH=10时1O2与p-ASA的反应速率常数为7.44×106 L·mol-1·s-1.
- Abstract：p-Arsanilic acid (p-ASA) is a kind of organoarsenic compound and is widely used as livestock and poultry feed additive for promoting animal growth in China. The use of p-ASA may release arsenic to the environment because it is mostly excreted by animals in its original form and can be oxidized to produce inorganic arsenic species. By using methylene blue (MB) as the photosensitizer and LED lamp (λ=660 nm) as the light source, singlet oxygen (1O2) was produced in aqueous solutions and the oxidative degradation of p-ASA by 1O2 was investigated thereafter. Several factors such as initial pH value, light intensity, initial concentration of methylene blue were investigated. The results show that p-ASA could be significantly degraded by 1O2 and inorganic As (V) was the final product. Under alkaline conditions, p-ASA was degraded significantly. The degradation rate of p-ASA was positively correlated with light intensity. The degradation rate of p-ASA was obviously improved with the increasing MB concentration and then became constant when the MB concentration was raised to above 3 mg·L-1. The second-order rate constant for the reaction between singlet oxygen and p-ASA in aqueous solution at pH 10 was determined to be 7.44 x 106 L·mol-1·s-1 by using competitive kinetic method with furfuryl alcohol (FFA) as a reference.
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