几种铵盐对土壤吸附Cd2+和Zn2+的影响

采用平衡吸附法，研究了不同铵盐对潮褐土、红壤吸附Cd2+、Zn2+的影响。结果表明，土壤对Cd2+、Zn2+的吸附量随平衡溶液中Cd2+、Zn2+浓度的增加而增加；潮褐土和红壤对Cd2+、Zn2+的最大吸附量为:Zn2+ Cd2+，且潮褐土红壤；随NH4HCO3浓度的增加，两种土壤对Cd2+、Zn2+的吸附率显著提高，NH4Cl、NH4NO3和(NH4)2SO4抑制红壤对Cd2+、Zn2+的吸附及潮褐土对Cd2+的吸附，对潮褐土Zn2+的吸附率影响不显著；铵盐浓度相同时，红壤对Cd2+吸附率为:NH4HCO3NH4ClNH4NO3≈ (NH4)2SO4，红壤对Zn2+吸附率为:NH4HCO3NH4Cl NH4NO3(NH4)2SO4。

Effects of NH4+salts on sorption of Cd2+and Zn2+in soils

The effects of different NH₄⁺ salts on Cd²⁺ and Zn²⁺ sorption in meadow cinnamon soils (MCS) and red soils (RS) were evaluated by batch method. The results showed that Cd²⁺ and Zn²⁺ amounts adsorbed by soils increased with the initial concentrations of added Cd²⁺ and Zn²⁺. The maximum amount of Cd²⁺ and Zn²⁺ sorption on MCS and RS were: Zn²⁺> Cd²⁺. The maximum amount of heavy metal ions adsorbed on soils was greater in meadow cinnamon soil than in red soil. The sorption percentage of Cd²⁺ and Zn²⁺ by soils decreased in the presence of NH₄HCO₃. NH₄⁺ salts, such as NH₄Cl, NH₄NO₃, and (NH₄)₂SO₄ restrained Cd²⁺ and Zn²⁺ sorption in RS and Cd²⁺ sorption in MCS. There was no significant effect of NH₄Cl, NH₄NO₃, and (NH₄)₂SO₄ on Zn²⁺ sorption in MCS. At the same concentration of NH₄⁺ salts, Cd²⁺ sorption percentage in RS was decreased in the following order: NH₄HCO₃>NH₄Cl>NH₄NO₃≈(NH₄)₂SO₄, and Zn²⁺ sorption percentage in RS in the following order: NH₄HCO₃>NH₄Cl>NH₄NO₃>(NH₄)₂SO₄.