阴离子交换树脂回收土壤淋洗液中的EDTA-Cd
发布时间：2018-07-16 12:54
【摘要】：以湖南株洲污染土壤作为研究对象,研究了Na-EDTA、NH_4-EDTA、Ca-EDTA在不同浓度下对土壤中Cd的去除效果,确定出适合的浓度与淋洗剂;并采用氯型717阴离子交换树脂对土壤淋洗液中的EDTA-Cd络合物进行吸附与回收试验,主要方法流程如下:采用静态法考察了固液比、pH值、时间、温度对树脂吸附EDTA-Cd络合物的影响,确定最佳吸附条件;采用上柱吸附法研究了在不同流速下穿透曲线的变化,确定树脂的穿透点;选取Fe_2(SO_4)_3多价金属盐溶液作为再生剂,对树脂中的EDTA-Cd络合物进行动态洗脱回收,测定出洗脱曲线与体积.随后进行连续5次吸附洗脱试验,探究树脂的再生性与树脂中EDTA-Cd络合物的回收效果.结果表明,在浓度为2.5 mmol·L~(-1)时,Na-EDTA、NH_4-EDTA、Ca-EDTA溶液对土壤中的Cd具有较好的去除效果,其去除率分别为64.75%、66.11%、68.29%.另外,在静态吸附过程中,随着固液比增加,树脂对EDTACd的吸附效率减少,在pH值为5.6时,对EDTA-Cd络合物吸附效率达到93.53%,树脂达到吸附平衡所需的时间为30—45 min,最佳反应温度区间为25—35℃;在动态吸附回收过程中,当上柱流速为4 m L·min~(-1)时,树脂达穿透点所需EDTA-Cd络合溶液为650 m L;再生剂Fe_2(SO_4)_3的洗脱体积为60 m L,洗脱溶液与吸附EDTA-Cd络合物溶液的体积比例达到1∶10.经过连续5次吸附洗脱试验后,树脂对EDTA-Cd络合物的去除率和再生率分别达到76.64%—93.43%、75.65%—84.19%.利用氯型717阴离子交换树脂提取以及回收土壤淋洗液中EDTA-Cd络合物是可行的.
[Abstract]:The effects of Na-EDTA-NH4-EDTA-Ca-EDTA on the removal of CD in soils at different concentrations were studied, and the suitable concentration and eluant were determined. The adsorption and recovery of EDTA-Cd complex in soil eluate by chlorine 717 anion exchange resin were studied. The main process was as follows: the effects of pH value, time and temperature on the adsorption of EDTA-Cd complex were investigated by static method. The optimum adsorption conditions were determined; the change of penetration curve at different flow rates was studied by the method of column adsorption, and the penetration point of resin was determined. Fe2 (SO4) 3 polyvalent metal salt solution was selected as regeneration agent for dynamic elution and recovery of EDTA-Cd complex in resin. The elution curve and volume were determined. The regeneration of the resin and the recovery of the EDTA-Cd complex from the resin were investigated by five successive adsorption elution tests. The results showed that when the concentration was 2.5 mmol L ~ (-1), the solution of Na-EDTANH _ 4-EDTACa-EDTA had a better effect on the removal of CD in soil, and the removal rates were 64.75 and 66.11and 68.29, respectively. In addition, in the static adsorption process, the adsorption efficiency of EDTACD decreased with the increase of solid-liquid ratio, and the adsorption efficiency of EDTACD was decreased at pH 5.6. The adsorption efficiency of EDTA-Cd complex is 93.53, the adsorption equilibrium time of resin is 30-45 min, the optimum reaction temperature range is 25-35 鈩，
本文编号：2126453
[Abstract]:The effects of Na-EDTA-NH4-EDTA-Ca-EDTA on the removal of CD in soils at different concentrations were studied, and the suitable concentration and eluant were determined. The adsorption and recovery of EDTA-Cd complex in soil eluate by chlorine 717 anion exchange resin were studied. The main process was as follows: the effects of pH value, time and temperature on the adsorption of EDTA-Cd complex were investigated by static method. The optimum adsorption conditions were determined; the change of penetration curve at different flow rates was studied by the method of column adsorption, and the penetration point of resin was determined. Fe2 (SO4) 3 polyvalent metal salt solution was selected as regeneration agent for dynamic elution and recovery of EDTA-Cd complex in resin. The elution curve and volume were determined. The regeneration of the resin and the recovery of the EDTA-Cd complex from the resin were investigated by five successive adsorption elution tests. The results showed that when the concentration was 2.5 mmol L ~ (-1), the solution of Na-EDTANH _ 4-EDTACa-EDTA had a better effect on the removal of CD in soil, and the removal rates were 64.75 and 66.11and 68.29, respectively. In addition, in the static adsorption process, the adsorption efficiency of EDTACD decreased with the increase of solid-liquid ratio, and the adsorption efficiency of EDTACD was decreased at pH 5.6. The adsorption efficiency of EDTA-Cd complex is 93.53, the adsorption equilibrium time of resin is 30-45 min, the optimum reaction temperature range is 25-35 鈩，
本文编号：2126453
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