摘要
采用振荡活化方法,探究44种有机酸对碳酸镉的活化差异及其机理,评价活化能力较强的5种有机酸对低浓度Cd污灌菜园土的活化效应。结果表明:低分子有机酸、酚酸及氨基酸对碳酸镉的活化能力存在明显差异;低分子有机酸活化能力总体较强,其中草酸、柠檬酸活化率达7.48%、7.06%。等摩尔浓度有机酸活化效果计算表明:柠檬酸的活化效果最大,活化量为22.73 mg·L^(-1),其次是苹果酸和顺乌头酸,分别为14.55和12.75 mg·L^(-1),酚酸的活化效果不明显,氨基酸中除天冬氨酸、组氨酸和谷氨酸活化效果较强,其余无明显效果。研究表明在等摩尔浓度时,柠檬酸活化碳酸镉主要机制为官能团的螯合作用,而草酸主要为酸溶作用;活化碳酸镉能力较强的柠檬酸对污灌菜园土低浓度Cd的活化最强,对镉的活化量达到食品安全风险水平。
This paper investigated the impact of 44 organic acids on mobilization of cadmium carbonate. The impact of five organic acids with best performance on Cd mobilization in garden soil was also examined. The results showed that the mobilization ability of low molecular weight organic acids（LMWOAs）,phenolic acids（PAs）and amino acids（AAs） on cadmium carbonate were significantly different. The mobilization ability of LMWOAs was stronger than PAs and AAs. The mobilization rates of oxalic acid and citric acid were 7. 48% and 7. 06%,respectively. Based on equivalent molarity of organic acid,the mobilized Cd by citric acid was 22. 73 mg·L^-1,followed by malic acid and cis-aconitic acid,which were 14. 55 mg ·L^-1and 12. 75 mg ·L^-1,respectively.The effect of PAs mobilization is not obvious. Among AAs,the mobilization effect of aspartic acid,histidine and glutamate was relatively strong and the rest were not significant. The main mechanism of Cd mobilization by citric acid was complexing,while the acid-soluble effect mainly contributes to Cd mobilization by oxalic acid. The citric acid with strongest ability to cadmium carbonate mobilization also had strongest ability to mobilize Cd in sewage-irrigated soil,and its mobilized Cd concentration reached the level of food safety risk.
出处
《环境工程学报》
CAS
CSCD
北大核心
2017年第9期5298-5306,共9页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(41371321)
广东省科技计划项目(2016A020221015
2017A010105005)
关键词
有机酸
碳酸镉
活化
organic acid
cadmium carbonate
mobilization
