摘要
本文对Ｃｕ￣（２＋）、Ｚｎ￣（２＋）、Ｃｏ￣（２＋）、Ｎｉ￣（２＋）和Ｃｄ￣（２＋）在砖红壤、针铁矿、无定形氧化铝和高岭石表面上的专性吸附进行的研究结果表明：ｐＨ是影响重金属离子吸附过程的最重要因素，而表面带电性质对吸附过程的影响不大。砖红壤表面的吸附顺序是Ｃｕ￣（２＋）＞Ｚｎ￣（２＋）＞Ｃｏ￣（２＋）＞Ｎｉ￣（２＋）≥Ｃｄ￣（２＋）；针铁矿表面的吸附顺序是Ｃｕ￣（２＋）＞Ｚｎ￣（２＋）＞Ｃｄ￣（２＋）＞Ｎｉ￣（２＋）＞Ｃｏ￣（２＋）；而无定形氧化铝和高岭石表面的吸附顺序是Ｃｕ￣（２＋）＞Ｚｎ￣（２＋）＞Ｎｉ￣（２＋）＞Ｃｏ￣（２＋）≥Ｃｄ￣（２＋）。重金属离子在四种材料上的吸附过程符合三层络合模式：（式中Ｓ为表面；Ｍ为重金属离子；Ｋ＿Ｍ（ｉｎｔ）是本征络合常数；Ｑ＿Ｍ是表观络合常数；ｅｘｐ为指数函数；ｅ为电子电荷；ψ＿０为表面电位；ψ＿β为Ｓｔｅｒｎ层电位，Ｒ为气体常数；Ｔ为绝对温度。用吸附数据求得的－ＬｏｇＱ＿Ｍ与σ＿０（表面电荷密度）之间呈极显著直线相关（α＝０．０１）。模型参数Ｋ＿Ｍ（ｉｎｔ）和内层电容θ＿１可用来表征表面与Ｍ￣（２＋）吸附亲和大的大小。在本文所测试的五种离子中，Ｃｕ￣（２＋）与表面?
The
specific adsorption of divalent Cu￣(2+), Zn￣(2+), Co￣(2+), Ni￣(2+) and Cd￣(2+) on
latosol,goethite, amorphous Al oxide, and kaolinite was measured as a function of pH.The
adsorption of heavy metals with increasing pH was in the order of Cu￣(2+) >Zn￣(2+)>Co￣
(2+)>Ni￣(2+)≥ Cd￣(2+) on latosol, Cu￣(2+)> Zn￣(2+) > Cd￣(2+)> Ni￣(2+)> Co￣(2+) on
goe-thite and Cu￣(2+)>Zn￣(2+)> Ni￣(2+)> Co￣(2+)≥ Cd￣(2+) on amorphous Al oxide and
kaolinite.The adsorption data are consistent with the triple layer model. The interfacial reac-tion
is described by the equationwhere Q_M= [(SO)_2M][H￣+]￣2/[SOH]￣2[M￣(2+)],ψ_0 is the
surface potential and ψ_β isthe mean potential at the plane of specifically adsorbed ions.
The affinity of Cu￣(2+)for surface was the largest, while the distance between surface and the
plane ofCu￣(2+) adsorbed was the shortest among the ions tested.
出处
《土壤学报》
CAS
CSCD
北大核心
1995年第4期370-376,共7页
Acta Pedologica Sinica
关键词
砖红壤
矿物表面
重金属离子
专性吸附
Specific
adsorption, Triple layer model, Heavy metal cations,Variable charge surface
