柠檬酸浸出土壤中铜、锌的优化设计

以某工业废弃地土壤为供试材料,采用批次实验方法,研究了柠檬酸对重金属Cu、Zn的浸出效果。并在单因素实验基础上,探讨不同pH值、柠檬酸浓度、固液比和浸提时间等对浸出效果的影响,进而对实验条件进行正交优化组合,确定优化工艺参数为：pH值为3.2,柠檬酸浓度为0.4 mol/L,壤土固液比为1/10,土壤中Cu、Zn接近平衡的时间分别为1 h和1.5 h。结果表明,在此条件下,对这2种金属来说,Cu较Zn易释放,Cu、Zn的最大浸出率分别为74.8%和65.3%。柠檬酸浸提前后,土壤中有机质含量下降范围为0.61%~3.16%。单从土壤有机质含量来看,柠檬酸对土壤质量影响较小,具有较好的应用前景。

Optimal design to extract Cu and Zn from mixed contaminated soils with heavy metals by citric acid

In a series of batch experiments,citric acid was used to remediate Cu and Zn contaminated soil derived from an industrial wasteland to study the extraction efficiency.Based on the single factor experiment,the effects of pH,citric concentration,liquid-solid ratios and reaction time were investigated.Then,the orthogonal test was prepared to optimize parameters,which was determined to be pH value of 3.2,citric concentration of 0.4 mol / L,loam liquid-solid ratio of 1 /10,equilibrium time of extraction for Cu in 1 hour and for Zn in 1.5 hour.The results showed that Cu was more releasable than Zn,and they had the highest leaching rate,reaching 74.8% and 65.3%,respectively.Organic matter content in soil in this study was reduced by 0.61% to 3.16% after extraction.In the case of soil organic matter content,citric acid has little effect on soil quality and could be a promising method for practical use in the future.