湘南红壤对NO_3~-和SO_4~(2-)的吸附机理研究

本文研究了湘南第四纪红粘土发育的红壤对NO_3和SO_4~(2-)的吸附等温线。结果表明红壤对NO_3~-的吸附在浓度低时为负吸附,浓度高时为正吸附,吸附机理为非专性吸附,红壤对SO_4~(2-)的吸附等温式以Freundlich方程最好,在达到最大吸量(X_m)之前,SO_4~(2-)以置换羟基(—OH)的配位吸附为主;而在达到最大吸附量以后,以非专性物理吸附为主。

A STUDY ON MECHANISMS OF NO_3~-ANDSO_4~(2-)ADSORPTION ON RED SOIL INSOUTHERN HUNAN PROVINCE

In this article, NO, and SO42- adsorption isotherms on red soil developed from Quaternary Red Clay in southern Hunan Province were studied. The results showed that NO3- adsorption by the soil was negetive when concentrations of NO3- in the equilibrating solution were low, but it was positive when the concentrations were higher. The mechanism of the NO3-adsorption was non-specific. However, the most suitable isotherm equation for describing SO42- adsorption by the soil was Freundlich equation, and it was suggested by the authors that most of the sulphate had been adsorbed by red soil with a specific adsorption mechanism through the displacement of hydroxyl ion (-OH) in the surface of soil particals before achieving the maximum value of SO42-- adsorption (Xm) by the soil, while beyond which a non-specific physics adsorption mechanism was the prevalent mechanism.