花岗岩上发育的几种土壤表面氟、磷、硫的竞争吸附

Competitive Adsorption of Fluoride, Phosphate and Sulphate to Some Soils Derived From Granite

对中南地区花岗岩上发育的５种土壤的氟吸附特征及其与磷、硫竞争吸附的研究结果表明：（１）土壤对氟的吸附量随加入氟浓度增大而增加，且在吸附时不断释放ＯＨ－，使平衡液ｐＨ升高。氟吸附容量的大小次序为：红壤＞赤红壤＞黄棕壤和砖红壤。氟吸附与Ｌａｎｇｍｕｉｒ方程、Ｆｒｅ－ｕｎｄｌｉｃｈ方程和Ｔｅｍｋｉｎ方程有极好的拟合性；（２）氟、磷、硫之间存在着竞争吸附，在磷酸根或硫酸根存在时，土壤对氟的吸附量增加，氟吸附等温线位置上移，曲线斜率变大。

The adsorption of fluoride and its competitive adsorption with phosphate or sulphate on 5 kinds of soils derived from granite,in middlesouth China,were studied.Results indicated that:(1) The amount of fluoride adsorption increased with the increasing of flouride concentration and the pH value of equilibrium solution raised with the releasing of OH- in the process of F- adsorption.The order of F- adsorption capacity was as follows:red soil>lateritic soil>yellow brown soil and latosol.The trial data of F- adsorption in the examined soils significantly well conformed to the Langmuir,Freundlich and Temkin equations(r=0.9552-0.998**).(2)There was a competitive adsorption among fluoride,phosphate and sulphate,and the amount of soil adsorption of fluoride could be raised with the occurrence of phosphate or sulphate.The effect of phosphate on soil adsorption of fluoride was more remarkable than that of sulphate.