农田土壤重金属淋洗剂筛选与效应分析
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杨文俊(1995-),男,在读硕士研究生,主要从事土壤污染与控制研究。E-mail:646309109@qq.com

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X53

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国家重点研发计划项目(2017YFD0801105);中央级科研院所基本科研业务费专项(Y2018LM18)


Screening and Effect Analysis of Eluents Removing Heavy Metals from Paddy Soil
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    摘要:

    为分析不同淋洗剂在不同淋洗条件下对重金属淋洗效果的影响,采用振荡淋洗法对比研究4种淋洗剂(柠檬酸(CA)、酒石酸(TA)、乙二胺四乙酸二钠盐(EDTA)和氨三乙酸三钠盐(NTA))不同浓度、淋洗时间、pH和固液比对重金属复合污染农田土壤中Pb、Cd、Cu和Zn的淋洗效果及单因素最佳淋洗条件下土壤淋洗前后重金属不同形态含量的变化。结果表明,CA和TA的最佳淋洗浓度为0.3 mol/L,EDTA和NTA为0.05 mol/L;CA和NTA的最佳淋洗时间为480 min,EDTA和TA为720 min;4种淋洗剂的最佳淋洗pH均为3,最佳固液比均为1∶20。单因素最佳淋洗条件下,EDTA对土壤重金属去除效果最佳,对Pb、Cd、Zn和Cu的去除率分别为67.4%,61.0%,13.8%和76.0%;NTA效果次之,去除率分别为41.6%,42.4%,9.9%和54.3%。土壤重金属去除率随淋洗剂pH的降低而升高,随固液比的增加而增加,随淋洗剂CA与TA浓度增大而增大。淋洗剂对土壤重金属的解吸动力学曲线符合准二级动力学模型,解吸过程为化学解吸,且解吸反应速率受土壤重金属含量与淋洗剂浓度控制。土壤重金属在淋洗剂作用下的解吸速率为Cd>Pb≈Zn≈Cu。EDTA和NTA淋洗显著降低土壤中Pb、Cd、Zn和Cu铁锰氧化态和有机结合态的含量,CA和TA显著降低Pb、Cd、Zn和Cu铁锰氧化态的含量。淋洗剂对重金属的去除效率为EDTA > NTA > CA > TA。

    Abstract:

    To study the removal effects of different eluents on heavy metals contaminated soil with different leaching conditions, a batch experiment was conducted to compare the effects of four eluents (citric acid (CA), tartaric acid (TA), ethylene diaminetetra acetic acid disodium salt (EDTA), and triacetintrisodium salt (NTA)) on removing heavy metals (Pb, Cd, Cu and Zn) from a paddy soil at different concentrations, leaching time, pH values and solid-liquid ratios. Changes in fractions of heavy metals in soil before and after leaching with eluents were analyzed at single factor optimal leaching conditions. The results showed that the optimum leaching concentrations were 0.3 mol/L CA and TA, and were 0.05 mol/L for EDTA and NTA; the optimal leaching time was 480 min for CA and NTA, and was 720 min for EDTA and TA; the optimum leaching pH value was 3 for all 4 eluents; and the optimum solid-liquid ratio was 1:20 for all 4 eluents. At the single factor optimal leaching conditions, EDTA had the best effects removing heavy metals from paddy soil, and the removal rates were 67.4%, 61.0%, 13.8% and 76.0% for Pb, Cd, Zn and Cu, respectively, followed by NTA, and the removal rates were 41.6%, 42.4%, 9.9% and 54.3%, respectively. The removal rates of heavy metals increased with the decreasing eluention pH values, with the increasing solid-liquid ratios, and with the increasing CA and TA concentrations. The desorption kinetics curves of the eluents removing heavy metals from paddy accorded with the pseudo second-order kinetic model. The desorption process was mainly a chemical desorption, and the desorption rates were controlled by heavy metal contents in soil and eluent concentrations. The desorption rates of heavy metals from soil followed the sequence of Cd>Pb≈Zn≈Cu. EDTA and NTA leaching significantly reduced the contents of iron/manganese oxidation and organic binding fractions of Pb, Cd, Zn and Cu, and CA and TA leaching significantly decreased the contents of iron/manganese oxidation fraction of these four heavy metals. The efficiency of the eluents removing heavy metals was EDTA > NTA > CA > TA.

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杨文俊, 辜娇峰, 周航, 黄芳, 王诗龙, 张竞颐, 龙坚, 袁腾跃, 廖柏寒.农田土壤重金属淋洗剂筛选与效应分析[J].水土保持学报,2019,33(4):321~328

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  • 收稿日期:2019-02-21
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  • 在线发布日期: 2019-08-19
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