【摘要】：以湖南株洲污染土壤作為研究對象,研究了Na-EDTA、NH_4-EDTA、Ca-EDTA在不同濃度下對土壤中Cd的去除效果,確定出適合的濃度與淋洗劑;并采用氯型717陰離子交換樹脂對土壤淋洗液中的EDTA-Cd絡(luò)合物進行吸附與回收試驗,主要方法流程如下:采用靜態(tài)法考察了固液比、pH值、時間、溫度對樹脂吸附EDTA-Cd絡(luò)合物的影響,確定最佳吸附條件;采用上柱吸附法研究了在不同流速下穿透曲線的變化,確定樹脂的穿透點;選取Fe_2(SO_4)_3多價金屬鹽溶液作為再生劑,對樹脂中的EDTA-Cd絡(luò)合物進行動態(tài)洗脫回收,測定出洗脫曲線與體積.隨后進行連續(xù)5次吸附洗脫試驗,探究樹脂的再生性與樹脂中EDTA-Cd絡(luò)合物的回收效果.結(jié)果表明,在濃度為2.5 mmol·L~(-1)時,Na-EDTA、NH_4-EDTA、Ca-EDTA溶液對土壤中的Cd具有較好的去除效果,其去除率分別為64.75%、66.11%、68.29%.另外,在靜態(tài)吸附過程中,隨著固液比增加,樹脂對EDTACd的吸附效率減少,在pH值為5.6時,對EDTA-Cd絡(luò)合物吸附效率達到93.53%,樹脂達到吸附平衡所需的時間為30—45 min,最佳反應(yīng)溫度區(qū)間為25—35℃;在動態(tài)吸附回收過程中,當上柱流速為4 m L·min~(-1)時,樹脂達穿透點所需EDTA-Cd絡(luò)合溶液為650 m L;再生劑Fe_2(SO_4)_3的洗脫體積為60 m L,洗脫溶液與吸附EDTA-Cd絡(luò)合物溶液的體積比例達到1∶10.經(jīng)過連續(xù)5次吸附洗脫試驗后,樹脂對EDTA-Cd絡(luò)合物的去除率和再生率分別達到76.64%—93.43%、75.65%—84.19%.利用氯型717陰離子交換樹脂提取以及回收土壤淋洗液中EDTA-Cd絡(luò)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，

本文編號：2126453