摘要
为探究植被根系分泌物的主要成分低分子有机酸对汞氧化还原反应的影响,采用室内模拟试验,探讨了酒石酸、柠檬酸及琥珀酸对汞的还原、氧化反应的影响,并分析了其相应的作用机制.结果表明,酒石酸对汞还原反应有明显的促进作用,柠檬酸有抑制作用.低浓度琥珀酸对汞还原反应有促进作用,高浓度为抑制作用.酒石酸还原Hg2+的反应为二级动力学反应,速率常数为0.0014~0.0056 L·(ng·min)-1.3种有机酸在反应初期对Hg0表现出一定的氧化作用,但随后被氧化的Hg0又被重新还原.3种有机酸对Hg0的氧化能力顺序为:柠檬酸>酒石酸>琥珀酸.
To study the effects of the main component of vegetation root exudates-low molecular weight organic acids on the redox reactions of mercury,laboratory experiments were conducted to investigate the roles of tartaric,citric,and succinic acid in the redox reactions of mercury,and to analyze their interaction mechanism. The results indicated that tartaric acid significantly stimulated the mercury reduction reaction,while citric acid had inhibitory effect. Succinic acid improved the reduction rate at low concentration,and inhibited the reaction at high concentration. The mercury reduction rate by tartaric acid treatment was second-order with respect to Hg2 +concentration,ranging from 0. 001 4 L·( ng·min)-1to 0. 005 6 L·( ng·min)-1. All three organic acids showed a capacity for oxidating Hg0 in the early stage,but the oxidized Hg0 was subsequently reduced. The oxidation capacity of the three organic acids was in the order of citric acid > tartaric acid > succinic acid.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2014年第6期2193-2200,共8页
Environmental Science
基金
国家重点基础研究发展规划(973)项目(2013CB430004)
国家自然科学基金项目(41373113
41173116)
中国博士后科学基金项目(2013M542242)
关键词
汞
还原
氧化
酒石酸
柠檬酸
琥珀酸
mercury
reduction
oxidation
tartaric acid
citric acid
succinic acid
