融雪剂对Cd在土壤中吸附规律及动力学影响

Effect of De-Icing Salt on Adsorption Law and Kinetics of Cadmium in Soil

摘要: 融雪剂中NaCl是人为加入土壤中的化学成分。通过等温吸附试验和吸附动力学试验，研究了NaCl对贵州铜仁、黔东南、黔南三个地区道路周边混合黄壤中Cd²⁺的吸附行为。1) Cd²⁺在土壤中的吸附行为由于溶液中加入NaCl而有所差异。在NaCl作用下，三地区土样对两种重金属的吸附能力降低。对于不同重金属，三地区土样的吸附能力顺序有所不同。2) 在NaCl作用下，Cd²⁺的解吸率由原来的8.69%~43.3%增加17.5%~54.1%。3) 两种吸附液中三地区土样对Cd²⁺的吸附用Langmuir模式来拟合较合适。在低浓度范围用Henry模式拟合比较合适，而在高浓度时适合用Langmuir拟合比较合适。4) 动力学试验表明：Elovich方程拟合出的相关系数最高可达0.9098，最适合描述动力吸附过程。由拟合参数计算出，在有无NaCl作用下，而对Cd²⁺作用效果不明显。

Abstract: NaCl in De-icing Salt is one of chemical components in soil itself. An investigation on the effects of NaCl on adsorption of Cd²⁺ in the Tongren, Qiandongnan, Qiannan in Guizhou province were carried out using isothermal adsorption and kinetic experiment. 1) The adsorption behaviour of Cd²⁺ was different when NaCl was added into solution. Under the action of NaCl, three regional soils adsorption capacity of the metals were lower. About different metals, the adsorb ability order of three regional soils was different. 2) Under the action of NaCl, the desorption rate of Cd²⁺ was from 8.69% - 43.3% to 17.5% - 54.1%. 3) The more suitable mode for the two types of solution in three regions to adsorb Cd²⁺ is Langmuir mode. The low concentration range was suitable Henry, but the high concentration range was suitable Langmiur. 4) Elovich equation has the highest correlation coefficient, and most suitable description of kinetic adsorption process. The highest R2 is 0.9098. From the parameters, under and without NaCl, Cd²⁺ had no effect.