【摘要】 【目的】土壤淋洗是快速去除污染土壤中重金属的实用修复技术之一,但成本低廉、高效且环境友好淋洗剂的研究报道仍然较少。【方法】采用振荡淋洗法研究了2-羟基膦酰基乙酸(HPAA)、巯基琥珀酸(MSA)和十水焦磷酸钠(SPP)3种生物易降解螯合剂在不同浓度、pH及时间下对两种污染土壤中重金属的淋洗效率。【结果】3种试剂对土壤Pb、Cd和Zn的去除率随浓度增加而逐渐提升(P<0.05),且总体上HPAA和MSA的去除率优于SPP。在淋洗浓度为0.05 mol/L,p H值为4和时间为60 min条件下,HPAA对两种土壤Pb、Cd和Zn的去除率分别为3.69%～18.44%、21.74%～38.34%和19.17%～52.95%,而MSA相应是25.91%～39.86%、11.84%～17.03%和19.37%～38.25%。它们对重金属的去除率随淋洗液pH值的升高而呈现不同的变化趋势,随淋洗时间的延长呈准一级动力学和准二级动力学反应过程。因此,HPAA和MSA是可适用于去除复合污染土壤中Pb、Cd和Zn的两种淋洗剂。更多还原

【Abstract】 【Objective】TSoil washing is one of the feasible techniques that remove heavy metals from contaminated soils. However,limited information is available on low cost,high efficiency and eco-friendly washing reagents.【Method】Three biodegradable chelators including 2-hydroxy phosphonoacetic acid(HPAA),mercaptosuccinic acid(MSA) and sodium pyrophosphate decahydrate(SPP) were used to remove cadmium,lead,and zinc from two contaminated soils near the mine under the different chelator concentrations solution p H values and durations.【Result】The removal efficiencies of Cd,Pb and Zn increased with increasing chelator concentrations(P<0.05). Generally,the efficiencies of soil Pb Cd and Zn by HPAA and MSA were higher than that by SPP. Under the conditions of 0.05 mol/L and pH4 of washing solution and duration of 60 min,the removal efficiencies of soil Cd,Pb and Zn by HPAA were 3.69%～39.86%,11.84%～38.34% and 19.17% ～52.95%,respectively. In addition,the removal efficiencies by MSA were 25.91%～39.86%,11.84%～17.03% and 19.37%～38.25%,respectively. They exhibited various changes with increasing p H values. Their reaction processes displayed pseudo-first and pseudo-second order models with prolonging durations.【Conclusion】HPAA and MSA are two relatively efficient biodegradable chelators removing Pb,Cd and Zn from contaminated soils.更多还原