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为明确铅、汞、镉和砷在通辽地区土壤中的吸附-解吸特征,采用批量平衡法,研究通辽地区4种典型土壤(草甸土、盐碱土、风沙土和栗钙土)对Pb(Ⅱ),Hg(Ⅱ),Cd(Ⅱ)和As(Ⅴ)的吸附-解吸行为,并分析影响吸附与解吸的因素。结果表明:1)Langmuir模型适合描述Pb(Ⅱ)和Cd(Ⅱ)在这4种土壤中的吸附特征,Freundlich模型适合描述Hg(Ⅱ)和As(Ⅴ)在这4种土壤中的吸附特征。2)4种土壤对重金属离子的吸附顺序是Pb(Ⅱ)>Hg(Ⅱ)>Cd(Ⅱ)>As(Ⅴ);4种土壤对4种重金属的吸附能力不同,对Pb(Ⅱ)的吸附量顺序是栗钙土>盐碱土>草甸土>风沙土,对Hg(Ⅱ)和Cd(Ⅱ)的吸附量顺序是草甸土>栗钙土>盐碱土>风沙土,对As(Ⅴ)的吸附量顺序是栗钙土>草甸土>盐碱土>风沙土。3)二次幂函数可以较好地拟合重金属离子解吸量与吸附量的关系。4)4种土壤对4种重金属离子解吸量顺序是As(Ⅴ)>Cd(Ⅱ)>Pb(Ⅱ)>Hg(Ⅱ);不同土壤对同一重金属离子的解吸量不同,对Pb(Ⅱ)和Cd(Ⅱ)的解吸量为:风沙土>盐碱土>栗钙土>草甸土,对于Hg(Ⅱ)的解吸量为:风沙土>草甸土>盐碱土>栗钙土,对于As(Ⅴ)的解吸量为:风沙土>盐碱土>草甸土>栗钙土。通辽地区4种典型土壤对铅、汞、镉和砷4种重金属的吸附、解吸行为是不同的。
In order to clarify the characteristics of adsorption and desorption of lead, mercury, cadmium and arsenic in soils of Tongliao area, four typical soils (meadow soil, saline soil, aeolian sandy soil and chestnut soil) in Tongliao area were used to study the effects of Pb ), Hg (Ⅱ), Cd (Ⅱ) and As (Ⅴ), and analyzed the factors affecting the adsorption and desorption. The results show that: 1) The Langmuir model is suitable for describing the adsorption characteristics of Pb (Ⅱ) and Cd (Ⅱ) in these four soils. Freundlich model is suitable for describing the adsorption characteristics of Hg (Ⅱ) and As . The adsorption order of Pb (Ⅱ)> Hg (Ⅱ)> Cd (Ⅱ)> As (Ⅴ) in four kinds of soils was different. The adsorption capacities of four soils to four heavy metals were different. The order of sorption amount was the sequence of chestnut soil> saline soil> meadow soil> aeolian soil. The order of adsorption amount of Hg (Ⅱ) and Cd (Ⅱ) was meadow soil> chestnut soil> saline soil> aeolian soil, Ⅴ) the order of adsorption is the chestnut soil> meadow soil> saline soil> aeolian soil. 3) The second power function can well fit the relationship between the amount of heavy metal ions desorbed and the amount of adsorption. (4) The order of desorption amount of four heavy metal ions in four soils is As (Ⅴ)> Cd (Ⅱ)> Pb (Ⅱ)> Hg (Ⅱ); Different desorption amounts of heavy metal ions in different soils are different, Desorption amounts of Cd (Ⅱ) were as follows: sandy soil> saline soil> chestnut soil> meadow soil. The desorption amount of Hg (Ⅱ) was as follows: aeolian soil> meadow soil> saline soil> (V) Desorption amount is: windy soil> saline-alkali soil> meadow soil> chestnut soil. The adsorption and desorption behaviors of four typical soils in Tongliao were different for the four heavy metals such as lead, mercury, cadmium and arsenic.