不同淋洗剂对镍污染砂土的柱淋洗研究

比较了去离子水、阴离子表面活性剂十二烷基硫酸钠（SDS）、盐酸和柠檬酸对模拟污染砂土中镍（Ⅱ）的柱淋洗作用。SDS浓度为500、1000、1750、2500和3250mg／L，盐酸溶液pH值为0．8、1、2和3，柠檬酸溶液浓度为0．01、0．04、0．1和0．4mol／L。结果表明，几种淋洗剂对土柱中镍的淋洗曲线规律相似，即在淋洗液孔隙体积数为0．5时开始有镍淋出，随着累计孔体积数目的增大，淋洗液中镍的浓度逐渐开始增大，迭到峰值时又开始减小。在去离子水淋洗过程中，镍最大淋出浓度为90．8mg/L；五种不同浓度SDS淋洗过程中，镍最大淋出浓度分别为92．4、90．2、94．1、51．0和53．7mg／L；四种不同pH值的盐酸溶液对应的镍最大淋出浓度分别为959．5、753．3、56．3和23．9mg／L；四种不同浓度的柠檬酸对应的镍最大淋出浓度分别为318．6、793．4、930．1和1464．4mg／L。pH=1的盐酸溶液对镍的淋洗去除率最高为87．3％，其次是浓度为0．1mol／L的柠檬酸溶液，去除率为83．2％；SDS的淋洗效率低，与去离子水相当。0．1mol／L的柠檬酸溶液可为污染土壤重金属镍淋洗用试剂。

Column Flushing of Nickel in Sandy Soils by Different Eluting Solutions

A comparative investigation on column flushing of nickel（II） in sandy soils by deionized water, an anionic surfactant（sodium dodecyl sulfate, SDS）, hydrochloric acid and citric acid was conducted. The concentrations of SDS were 5 00, 1000,1 750,2 500 and 3 250 mg/L. The pH values of hydrochloric acid solutions were 0. 8,1,2 and 3. The concentrations of citric acid solutions were 0. 01, 0. 04, 0. I and 0. 4 mol/L. The resuhs show that the tendency of elution curves by four eluent is similar. When the pore volume number of solution was 0. 5, nickel （II） concentration in eluting solution became to increase. Then nickel（II） concentration went up, got maximum value and went down with the pore volume number. The maximum nickel（II） concentrations were 90. 8 mg/L by deionized water,92. 4,90. 2,94. 1,51.0 and 53.7 mg/L by five SDS,959. 5,753.3,56. 3 and 23.9 mg/L by hydrochloric acid, and 318.6,793.4,930. 1 and 1464. 4 mg/L by citric acid, respectively. The highest removal efficiency of nickel（II） was 87.3% using hydrochloric acid with 1.0 of pH value. And the second one was 83.2% by citric acid with 0. 1 mol/L of concentration. The flushing capability of SDS was less and about equivalent to those by deionized water. The best eluent to flushing nickel（II） is citric acid at 0. 1 mol/L concentration.