磷在砖红壤土壤固-液界面的吸附反应特征研究

Characteristics of Absorption of Phosphate on the Latosol Solid-solution Interface

以砖红壤为研究对象,探讨了其对磷的吸附动力学及相关影响因素。结果表明,砖红壤对磷的吸附容量较高,磷初始浓度为2.0 mmol/L,土壤吸附磷后,溶液p H上升。由于有机酸可与磷酸根竞争表面吸附位点,所以有机酸的存在将抑制土壤对磷的吸附。土壤表面吸附磷后,有机酸溶解土壤过程中,Fe、Mn的释放量减少,进一步表明有机酸与磷酸根之间存在竞争作用。此外,草酸的抑制作用强于酒石酸。

Latosol was uesd to study adsorption kinetics of P and the influence of several solution factors.The results showed the Latosol had a high capacity for P.The maximum adsorption was not reached with the initial concentration of P as high as2.0 m M.Adsorption of P was rapid at the initial stage,following by a slow process.The change in solution p H exhibited the same trend.The presence of organic acids suppressed the adsorption of P,which was attributed to the competition between P and organic anions for reactive sites.The amounts of Fe and Mn releasing from the organic acids-promoted soil dissolution decreased once the soil was pre-adsorbed P.The inhibitive effect of tartaric acid on P adsorption was more strong than that of oxalic acid.