陕南茶叶产区土壤对Ni(Ⅱ)的吸附特征研究

Adsorption Characteristics of Tea-growing Areas Soil to Ni(Ⅱ) of Southern Shaanxi

为探明陕南茶叶产区土壤对Ni(Ⅱ)的吸附特性,本文用振荡平衡法研究了陕南茶叶产区典型土壤黄褐土对Ni(Ⅱ)的吸附特性,并用数学模型模拟其吸附动力学过程。结果表明,准一级动力学模型、准二级动力学模型适合于表征Ni(Ⅱ)的吸附动力学特征,其中一级动力学方程模拟效果最好;Freundlich模型能够较好地模拟Ni(Ⅱ)的吸附等温过程。吸附热力学计算模拟结果表明,黄褐土对于镍的吸附反应是个吸热过程,随着吸附反应温度上升,吸附反应越强烈。溶液的酸碱度是影响Ni(Ⅱ)去除效果的一个重要因素,pH>8.5时Ni(Ⅱ)几乎完全被去除。对土壤基本理化性质与吸附参数的相关分析说明,土壤有机质含量对重金属Ni(Ⅱ)的吸附起重要作用。该结果可为茶叶产区土壤预防重金属污染提供一定的理论依据。

In order to find out the adsorption characteristics of typical soil towards Ni （ Ⅱ） in tea-growing areas of southern Shaanxi, the adsorption behavior of typical soil to Ni（ Ⅱ ） was studied by vibration batch equilibrium techniques, the adsorption kinetics process by mathematical model was simulated. The results showed that the pseudo-first-order kinetic model, the pseudo-second-order kinetic model all could simulate the adsorption kinetics process of the soil to Ni （Ⅱ）, and the pseudo-first-order kinetic model was best. The absorption isothermal process of soil to Ni （Ⅱ） could well simulate by Freundlich model. The simulation results showed that the browns soil for nickel adsorption reaction was an endothermic process. With the increase of adsorption reaction temperature, the adsorption reaction was more strong. pH value had great infiuence on the removal efficiency of Ni （Ⅱ ） from aqueous solution, and Ni （ Ⅱ ） could be nearly completely adsorb when pH〉8.5. Through the relation analysis of basic physical and chemical properties of soil and adsorption parameters, combined with infrared spectrum analysis of soil before and after adsorption, it was showed that soil organic matter played an important role in adsorption of Ni （Ⅱ） .