| 摘要: |
| 【目的】使用生物表面活性剂（皂苷）、小分子有机酸（柠檬酸、苹果酸和草酸）对污染土娄土中的Cd进行淋洗，寻求各淋洗剂对污染土娄土Cd淋洗的最适条件，为强化植物修复重金属污染土壤提供参考依据。【方法】采用振荡淋洗批处理方法，研究皂苷、柠檬酸、苹果酸和草酸淋洗剂在不同时间、pH、浓度、淋洗次数、复合比条件下对污染土娄土中Cd的淋洗效果，用Sposito浸提法提取淋洗前后污染土娄土中的Cd，并分析其形态的变化。【结果】（1）0.01 mol/L草酸对污染土娄土中Cd无淋洗作用；其他淋洗剂对污染土娄土中Cd淋洗的最适条件为：淋洗时间240 min，pH 5.0，苹果酸、柠檬酸、皂苷淋洗的最适浓度分别为0.50，0.150，0.200 mol/L，对应最大的Cd淋洗百分率分别为39.86%，45.81%和17.4%；增加淋洗次数，可明显提高淋洗百分率。（2）皂苷与低浓度柠檬酸、苹果酸复配对污染土娄土中Cd的淋洗具有促进作用，当其物质的量之比分别为10∶3和4∶3时，对污染土娄土中Cd的复合淋洗效果最佳，Cd的淋洗百分率最大，分别可达37.09%，32.32%。（3）增加淋洗次数时，皂苷、柠檬酸、苹果酸促进了污染土娄土中各形态Cd的转变，土壤中碳酸盐结合态、有机结合态、硫化物残渣态Cd明显减少。【结论】皂苷、柠檬酸、苹果酸可用于强化植物修复重金属Cd污染土壤。 |
| 关键词: 土娄土 镉 皂苷 小分子有机酸 淋洗效果 |
| DOI： |
| 分类号: |
| 基金项目:陕西省农业科技攻关计划项目（2014K02-12-02） |
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| Washing efficiency of Cd from contaminated Lou soil by saponin and low-molecular-weight organic acids |
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LI Zhen,DENG Hongxia,GONG Zhengqing,et al
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| Abstract: |
| 【Objective】The washing of Cd from contaminated Lou soil was carried out by biosurfactants (saponins) and low molecular organic acids (citric acid,malic acid and oxalic acid) to find the optimum conditions,and to provide reference for the enhancement of plant remediation of heavy metal contaminated soil.【Method】Batch soil washing experiment was conducted to investigate the Cd washing efficiencies under the conditions of different contact time,pH values,concentration,washing time,compound ratio.Sposito extraction method was used to extract the different forms of Cd in contaminated Lou soil before and after washing.【Result】(1) 0.01 mol/L oxalic acid had no effect on the washing of Cd from contaminated Lou soil.The optimum conditions of the other eluents for the washing of Cd from contaminated Lou soil is 240 min and pH 5.0.The most suitable concentrations of malic acid,citric acid and saponin were 0.50 mol/L,0.150 mol/L,0.200 mol/L which corresponded to the washing percentage were 39.86%,45.81%,17.4%.The washing percentage were significantly improved with the increase of washing times;(2) The combination of saponin and low concentration of citric acid or low concentration of malic acid had an enhancement on the washing of Cd from contaminated Lou soil.When the ratio came to 10∶3 between the combination of saponin and low concentration of citric acid,or when the ratio came to 10∶4 between the combination of saponin and low concentration of malic acid,the washing percentage could be 37.09% and 32.32%,which were the best washing effect;(3) The increase of washing times by malic acid,citric acid and saponin lead to the transformation of Cd from contaminated Lou soil,specifically acted in the decrease of carbonate bound state,organic binding state and sulfide residue Cd in contaminated Lou soil.【Conclusion】The addition of saponin,citric acid and malic acid can be used to strengthen the effects of phytoremediation on heavy metal Cd contaminated soil. |
| Key words: Lou soil cadmium saponins low molecular organic acids washing efficiency |
