几种铵盐对土壤吸附Cd^2＋和Zn^2＋的影响

Effects of NH_4^+ salts on sorption of Cd^(2+) and Zn^(2+) in soils

采用平衡吸附法,研究了不同铵盐对潮褐土、红壤吸附Cd^(2+)、Zn^(2+)的影响。结果表明,土壤对Cd^(2+)、Zn^(2+)的吸附量随平衡溶液中Cd^(2+)、Zn^(2+)浓度的增加而增加;潮褐土和红壤对Cd^(2+)、Zn^(2+)的最大吸附量为:Zn^(2+)>Cd^(2+),且潮褐土>红壤;随NH_4HCO_3浓度的增加,两种土壤对Cd^(2+)、Zn^(2+)的吸附率显著提高,NH_4Cl、NH_4NO_3和(NH_4)_2SO_4抑制红壤对Cd^(2+)、Zn^(2+)的吸附及潮褐土对Cd^(2+)的吸附,对潮褐土Zn^(2+)的吸附率影响不显著;铵盐浓度相同时,红壤对Cd^(2+)吸附率为NH_4HCO_3>NH_4Cl>NH_4NO_3≈(NH_4)_2SO_4,红壤对Zn^(2+)吸附率为NH_4HCO_3>NH_4Cl>NH_4NO_3>(NH_4)_2SO_4。

The effects of different NH4^＋ salts on Cd^2＋ and Zn^2＋ sorption in meadow cinnamon soils （MCS） and red soil, （RS） were evaluated by batch method. The results showed that Cd^2＋ and Zn^2＋ amounts adsorbed by soils increased witt the initial concentrations of added Cd^2＋ and Zn^2＋ The maximum amount of Cd^2＋ and Zn2^＋ sorption on MCS and RS were：Zn^2＋ 〉 Cd^2＋ . The maximum amount of heavy metal ions adsorbed on soils was greater in meadow cinnamon soil than in red soil. The sorption percentage of Cd^2＋ and Zn^2＋ by soils decreased in the presence of NH4HCO3. NH4^＋ salts, such as NH4Cl, NH4NO3, and （NH4）2SO4 restrained Cd^2＋ and Zn^2＋ sorption in RS and Cd^2＋ sorption in MCS. There was no significant effect of NH4Cl, NH4NO3, and （NH4）2SO4 on Zn^2＋ sorption in MCS. At the same concentration o： NH4^＋ salts, Cd^2＋ sorption percentage in RS was decreased in the following order： NH4HCO3 〉 NI-I4Cl 〉 NH4NO3 （NH4）2SO4, and Zn^2＋ sorption percentage in RS in the following order： NH4HCO3 〉 NH4Cl 〉 NH4NO3 〉 （NH4）2SO4.