• 关键词：土壤  铅  阴离子  磷酸盐  稳定  镉  锌

• 基金项目：河南省教育厅自然科学研究计划项目(No.2011A610006)

• 邢维芹
• 河南工业大学化学化工学院, 郑州 450001

• 王亚利
• 河南工业大学化学化工学院, 郑州 450001

• 李立平
• 河南工业大学化学化工学院, 郑州 450001

• 向国强
• 河南工业大学化学化工学院, 郑州 450001

• 巩丹丹
• 河南工业大学化学化工学院, 郑州 450001

• 史丽兰
• 河南工业大学化学化工学院, 郑州 450001

• Kirk G Scheckel
• National Risk Management Research Laboratory, U. S. Environmental Protection Agency, Cincinnati, OH 45224, USA

• 摘要：在重金属污染土壤中加入磷酸盐是稳定重金属的有效方法.本研究的目的是探讨不同阴离子对水溶性磷酸盐稳定污染土壤铅、镉和锌的影响.在重金属复合污染土壤(全铅、镉和锌的含量分别为2337、21.4和391 mg·kg^-1)中按P:Pb=2:1 (mol:mol)加入磷酸二氢钙,之后按P:阴离子=3:1或3:2 (mol:mol)加入盐酸、氯化钠、硫酸、硫酸钠或氟化钠,并设置只加磷酸盐、不加其它试剂的对照,培养55 d,之后测定土壤性质.结果表明,与对照相比,HCl处理、2HCl处理、NaCl处理和2NaCl处理土壤DTPA-Pb含量下降比例依次为5.72%、9.29%、6.38%和8.80%(p<0.05),加入硫酸、硫酸钠的处理土壤DTPA-Pb含量与对照无显著差异(p>0.05),而加入氟化钠的处理升高4.70%(p<0.05).加入盐酸或氯化钠的处理土壤镉有效性显著高于对照(升高5.24%~12.8%)(p<0.05),其它处理对DTPA-Cd含量无显著影响(p>0.05).各处理对土壤DTPA-Zn含量和pH影响较小,但均引起土壤电导率明显升高.以上结果表明,氯离子可促进水溶性磷酸盐对土壤铅的稳定,但可促进镉有效性.氯磷酸铅的生成是加氯情况下磷酸盐稳定铅的重要机制.

• Abstract：An effective way to remediate heavy metal polluted soils is phosphate amendments. This work investigated the effect of different anions on the immobilization of heavy metals in soil with a soluble phosphate. A multi-heavy metal polluted soil (total Pb: 2337, total Cd: 21.4, and total Zn: 391 mg·kg^-1) was amended with calcium dihydrogen phosphate (Ca(H₂PO₄)₂) at the rate of P:Pb=2:1 (mol:mol), and HCl, NaCl, Na₂SO₄, H₂SO₄ or NaF were added at the rate of P:anion (mol:mol)=3:1 or 3:2. A control with phosphate amendment only was also set up. Soils were incubated for 55 days and then analyzed. The results indicated that, compared with the control, DTPA-extractable Pb of the soils amended with HCl (3:1), 2HCl (3:2), NaCl (3:1) and 2NaCl (3:2) decreased 5.72%, 9.29%, 6.38% and 8.80% (p<0.05), respectively, with no statistically significant difference found between the DPTA-extractable Pb concentrations of the H₂SO₄ and Na₂SO₄ amended soils and the control; however, the NaF amended soil increased 4.70% (p<0.05). DTPA-extractable Cd concentrations of soils amended with HCl or NaCl were 5.24%~12.8% higher than that of the control (p<0.05), and no significant difference was found between other amendments and the control (p>0.05). No robust effect of the anion amendments on the concentration of DTPA-extractable Zn and pH was observed, but all the amendments increased soil electrical conductivity. The results confirmed that chloride promotes the immobilization of Pb with soluble phosphate, and increases the availability of Cd. When chloride is added, a vital mechanism of Pb immobilization with soluble phosphates is the formation of chloropyromorphite.

• Key words：soil  Pb  phosphate  immobilization  anion  Cd  Zn

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