土壤矿物对汞的吸持特性研究

吸附热力学与动力学试验研究结果表明 ,5种土壤矿物对Hg的吸附容量与吸附强度均表现为MnO2 >Fe2 O3 >膨润土 >高岭土 >CaCO3 。MnO2 对Hg吸附容量大且固持能力强 ,CaCO3 则与之相反。各土壤矿物结合汞的形态分布特征表明各土壤矿物结合汞在不同环境的稳定性及相应数量比例。挥发试验结果表明各土壤矿物结合汞的环境活性 (挥发活性 )大小受土壤矿物对Hg吸附容量与吸附强度制约 ,并与矿物结合汞的形态分布特征相关 ,水溶交换态和酸溶态比例越高则土壤矿物结合汞挥发活性越强 ,碱溶态和残渣态比例越高则土壤矿物结合汞挥发活性相应越弱

Adsorption and bound characteristics of soil minerals with Hg

Adsorption thermodynamics and kinetics experiments indicate that the sequence of adsorption capacity as well as the adsorption strength of five types of soil minerals to Hg is MnO_2>Fe_2O_3>bentonite>kaolinite>CaCO_3. The differences of speciation distribution characteristics of mineral bound Hg can reflect the stability and corresponding quantity of mineral bound Hg under different environmental conditions. Volatilization experiment verifies that the environmental activity of mineral bound Hg is strongly influenced by its speciation distribution as well as the adsorption capacity and strength of minerals with Hg. The higher the proportions of water soluble and exchangeable Hg and acid soluble Hg are, the higher the environmental activity of the mineral bound Hg will be. The higher the proportions of alkali soluble and residual Hg are, the lower the environmental activity of the mineral bound Hg will be.