土壤中重金属铊的分级提取形态分析法研究

Modified Sequential Extraction Procedure for Thallium in Soils

以自然高铊污染土壤为样品, 对BCR标准分级提取形态分析法中争议较大的HAc和NH2OH·HCl提取剂pH、提取剂浓度和提取体系温度对土壤中相应形态Tl提取量的影响进行了研究。实验发现标准条件的HAc提取体系可有效提取土壤中可交换态的Tl, 而标准的NH2OH·HCl提取体系不能有效提取土壤中易还原态的Tl。根据实验结果, 对标准BCR法进行如下改进: NH2OH·HCl提取剂pH由2.0酸化至1.5, 提取剂浓度由0.1mol/L增至0.5 mol/L, 提取体系温度由室温(28℃)增至60℃; 其他提取条件不变。

A modified sequential extraction procedure for thallium in soil was developed using a high thallium polluted soil sample.Based on the BCR method,the pH and concentration of the extractant,and the effects of the temperature of HAc and NH 2 OH·HCl extract systems on the extracted amount of Tl species in soil were studied in detail.It was found that the HAc extractant used in BCR method could effectively extract the exchangeable Tl species,but the NH 2 OH·HCl extractant could not effectively extract the easily reducible Tl species.Experimental results showed that the extracted amount of Tl species from different minerals would be increased if the pH of NH 2 OH·HCl extractant was decreased to1.5,and its concentration and the extract system temperature were increased to0.5mol/L and60℃,respectively.