羟基磷灰石和氯化钾联用修复铅锌矿区铅镉污染土壤的研究

Remediation Pb,Cd Contaminated Soil in Lead-zinc Mining Areas by Hydroxyapatite and Potassium Chloride Composites

以湖南凤凰铅锌矿区的2个重金属污染土壤(HF-1、HF-2)为研究对象,利用组合制剂羟基磷灰石(HA)加氯化钾(KCl)修复矿区铅镉污染土壤,目的是探讨Cl-对HA修复重金属铅镉污染土壤的作用.每个实验土壤设置5个HA水平和4个KCl水平,共计40个处理,采用美国固体废弃物毒性浸提程序(TCLP)评价修复效果.结果表明,HA能够有效地降低污染土壤中的TCLP浸提态铅和镉;组合制剂在HA∶Pb∶KCl摩尔比为8∶1∶2时对土壤铅和镉的固化效果达到最佳,该处理下土壤HF-1、HF-2中铅和镉的固化率分别达到83.3%、97.27%和35.96%、57.82%;在HA∶Pb摩尔比为8的水平上,KCl∶Pb摩尔比为2时土壤HF-1、HF-2中铅和镉的固化率比未添加KCl时分别提高6.26%、0.33%和7.74%、0.83%.研究表明,适量的Cl-存在可以提高羟基磷灰石对重金属铅镉污染土壤的修复效果.

The composite agents containing potassium chloride （KC1） and Hydroxyapatite（HA） were used to remediate the lead and cadmium contaminated soil in Fenghuang lead-zinc mining-smelting areas, Hunan province. The objective of this study was to identify and evaluate the influence of Cl^- to the fixing efficiency of Pb and Cd by HA. Two types of contaminated soil （HF-1, HF-2） were chosen and forty treatments were set by five different Hydroxyapatite （HA） dosages and four different Cl^- dosages. The toxicity characteristic leaching procedure （TCLP） was used to evaluate the results. It showed that HA could efficiently fix the Pb and Cd from TCLP form. The maximum Pb-fixing efficiency and Cd-fixing efficiency of two types of soil were 83.3% , 97.27% and 35.96% , 57.82% when the HA： Pb： KCl molar ratio was 8： 1： 2. Compared to the fixing efficiency without KCl, KCl at the KCl： Pb molar ratio of 2 improved Pb-fixing efficiency and Cd-fixing efficiency by 6. 26% , 0. 33% and 7.74% , 0. 83% respectively when the HA： Pb molar ratio was 8. Generally, Cl^- can improve the Pb/Cd-fixing efficiency in heavy metal contaminated soil by Hydroxyapatite.