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中国科技论文在线
铁(III)-羟基配合物体系对草甘膦的光化学
转化作用
#
冯晓楠
1
,王宗平
1
,陈勇
1
,陶涛
1
,吴峰
2**
基金项目:中央高校基本科研业务费资助(HUST:2010QN052);高等学校博士学科点专项科研基金资助
课题(20100142120004);武汉市青年科技晨光计划(201050231074)
作者简介:冯晓楠,(1984-),女,博士研究生,主要研究方向:水污染控制及治理
通信联系人:陈勇,(1976-),男,讲师,主要研究方向:水处理高级氧化. E-mail: ychen@mail.hust.edu.cn
(1. 华中科技大学环境科学与工程学院,武汉 430074; 5
2. 武汉大学资源与环境科学学院,武汉 430074)
摘要:以草甘膦作为有机磷的代表性化合物,对其在 Fe(III)-羟基配合物体系中的光化学
转化规律进行了研究,并对光降解途径进行了初步探讨。实验中以 125W 的卤素灯(波长≥
365nm)为光源,在同心圆自转式反应装置上进行光化学反应;采用钼锑抗比色法检测草甘膦
的光化学转化产物 PO4-P;考查了溶液初始 pH 值、Fe(III)/羧酸盐配比、草甘膦的初始浓10
度等因子对草甘膦的光化学转化效率的影响。采用茚三酮显色实验定性地检测了草甘膦的光
降解产物。通过实验得出:溶液 pH 值为 3.0~7.0 时,草甘膦的光化学转化效率随溶液的
初始 pH 值升高而降低。当 Fe(III) 浓度为 100µmol• L-1,草甘膦的初始浓度为 2.0mg
• L-1,溶液的初始 pH 值为 7.0 时,草甘膦的光化学转化效率为 24.7%。
关键词:草甘膦;Fe(III)-羟基配合物;光化学转化 15
中图分类号:X52
Photochemical Transformation of Glyphosate in the
Presence of Fe(III)-hydroxo Complexes
Feng Xiaonan
1
, Wang Zongping
1
, Chen Yong
1
, Tao Tao
1
, Wu Feng
2
20
(1. School of Environmental Science and Engineering, Huazhong University of Science and
Technology, WuHan 430074;
2. School of Resource and Environmental Science, Wuhan University, WuHan 430074)
Abstract: Glyphosate (N-(phosphonomethel)glycine) was used as a probe compound of
organophosphorous to investigate its photochemical transformation behaviours in the 25
Fe(III)-hydroxo. A proposed pathway of photolysis for glyphosate in the complexes was
hypothetically presented. The photochemical transformation experiments were performed in a
centric photochemical reactor of rotating type with a 125W halogen lamp (λ ≥ 365 nm). The
concentrations of orthophosphate (PO4-P) were measured with a spectrophotometer at 700 nm.
The photochemical transformation efficiencies of glyphosate were analysed. The effects of initial 30
pH values, the Fe(III)/carboxylate ratios and the initial concentrations of glyphosate on the
photochemical transformation were investigated. To test for the possibility of C-N and C-P bond
cleavage during the iron(III)-mediated decomposition of glyphosate, the ninhydrin tests for
primary amines were run before and after irradiation.The main results and conclusion are
presented as following: the photochemical transformation efficiencies of glyphosate increase with 35
decreasing pH values in the pH range of 3.0-7.0. The cupric ions in the solution show inhibition
effect on the photochemical transformation. When the concentration of Fe(III) is 100 µmol• L-1,
the initial concentrations of glyphosate 2.0 mg• L-1,the initial pH value 7.0, 24.7% of glyphosate
can be chemically transformed into orthophosphate (PO4-P).
Keywords:
Glyphosate; Fe(III)-hydroxo; Photochemical transformation 40
0 引言
草甘膦是一种广泛使用的有机磷农药,有机磷农药是为替代有机氯农药而进入生产使用
的,相对与有机氯农药而言,它的降解速度较快,在生物食物链中富集程度较低。然而,随
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