Pb^(2+)在水稻土、黄褐土中的等温吸附特性

Isothermal Adsorption Characteristics of Pb^(2+) in Paddy Soil and Yellow-cinnamon Soil

[目的]为土壤重金属环境容量的制定和铅污染土壤的改良提供理论依据。[方法]采用一次平衡法研究水稻土和黄褐土对铅的吸附特性以及土壤加入H2PO4-后对铅吸附的影响。[结果]铅在水稻土、黄褐土中的吸附平衡均可采用Langmuir、Freundlich和Temkin等方程拟合,以Langmuir方程拟合最佳,用其求得水稻土、黄褐土对铅的最大吸附量均为5 000 mg/kg。水稻土和黄褐土对Pb2+的最大缓冲容量分别为666.67、1428.57 mg/kg,水稻土、黄褐土吸附H2PO4-后,对铅的吸附能力均有所增强,但最大吸附量都没有变化。[结论]两种土壤对铅的吸附能力较强,且都可用Langmuir、Freundlich、Temkin方程拟合。

[Objective] The objective of the research was to provide theoretical basis for establishing environmental capacity of heavy metals in soil and improving soil polluted by Pb. [Method] Once balance method was used to study the absorption characteristics of Pb in paddy soil and yellow-cinnamon soil and the effects of adding H2PO4^- to＇soil on Pb absorption. [Result] The absorption equilibrium of Pb in paddy soil and yellow-cinnamon soil could be fit with Langmuir, Freundlich and Temkin equations. Fitting with Langmuir equation was the best, with which the calculated maximum adsorption amounts of Pb in paddy soil and yellow-cinnamon soil were both 5 000 mg/kg. The maximum buffering capacities of Pb^2＋ in paddy soil and yellow-cinnamon soil were 666.67 and 1 428.57 mg/kg, respectively. After the paddy soil and yellow-cinnamon soil absorbed H2PO4^-, their absorption abilities of Pb were enhanced, but the maximum absorption amounts had no change. [Conclusion] Two kinds of soil had stronger absorption abilities to Pb and could all be fit with Langmuir, Freundlieh and Temkin equations.