化学强化洗脱修复硫化铜矿区周边农田污染土壤中的铅锰

Remediation of Pb/Mn of the Polluted Farmland Soils around the Cupric Sulfide Ore District by Chemical-enhanced Elution

研究了非离子型表面活性剂辛烷基苯酚聚氧乙烯醚(Triton X-100)、聚氧乙烯失水山梨糖醇单油酸酯(Tween-80)与螯合剂二乙三胺五醋酸(DTPA)强化洗脱污染土壤中的铅和锰。单一洗脱实验结果表明,当DTPA浓度为26.7 mmol L-1时,DTPA对污染区的供试土壤中铅的去除率达到52.49%,锰的去除率达到21.94%;而Triton X-100和Tween-80单独洗脱时对铅锰的洗脱效果不佳,洗脱率均小于3%。复配洗脱实验结果表明,DTPA的浓度较低时,Triton X-100和Tween-80对DTPA洗脱重金属铅的作用表现为协同增溶。当DTPA浓度为3.3 mmol L-1时,当Triton X-100与DTPA复配时,污染土壤中铅的去除率由2.68%增加到83.35%;当Tween-80与DTPA复配时,污染土壤中铅的去除率由2.68%增加到24.72%。但当DTPA的浓度为6.7mmolL-1时,加入Triton X-100或Tween-80抑制了DTPA对铅的洗脱,表现为拮抗作用。Triton X-100、Tween-80分别与DTPA复配实验结果表明,Triton X-100和Tween-80不适合与DTPA复配洗脱供试土样中的锰。

The enhanced elution of Pb and Mn from the polluted farmland soil around the cupric sulfide ore district were studied with Triton X-100, Tween-80 and Diethylenetriamine pentacetic acid(DTPA). The single elution experimental results showed that DTPA could efficiently remove Pb and Mn in soils. When the concentration of DTPA was 26.7 mmol L-1, the total removal rates of Pb and Mn were 52.49% and 21.94%. The elution effects of Pb and Mn with Triton X-100 and Tween-80 respectively were poor, all the removal rates were less than 3%. In addition, the compound elution experimental results showed that Triton X-100 and Tween-80 could significantly enhance the synergetic solubilization of Pb at lower concentration of DTPA. When the concentration of DTPA was 3.3 mmol L-1, the removal rates of Pb increased from 2.68%(by single DTPA) to 83.35% by using the mixture of Triton X-100 and DTPA, while the removal rate of Pb increased from 2.68%(by single DTPA) to 24.72% by using the mixture of Tween-80 and DTPA. However, when the concentration of DTPA was 6.7 mmol L-1, the adsorption of Pb from the soils was inhibitory by using DTPA + Triton X-100 or DTPA + Tween-80, which was assumed antagonism. The results of Triton X-100 + DTPA or Tween-80 + DTPA compound showed that Triton X-100 and Tween-80 were not suitable to compound with DTPA to remove Mn in soil.