几种可变电荷土壤中氧化铁类型与磷吸附特性

应用Ｘ射线衍射和化学分析等手段研究了红壤，砖红壤和黄棕壤中氧化铁类型及其与磷吸附和解吸的关系。结果表明：（１）黄棕壤中的氧化铁是针铁矿型，砖红壤和红壤是以赤铁矿为主，棕红壤是以针铁矿为主的针－赤混合型。（２）针铁矿的ＭＣＤ值一般小于赤铁矿的ＭＣＤ值，前者的比表面积大，后者的小。砖红壤中的赤铁矿晶体薄，红壤中的原。（３）针铁矿型氧化铁的磷吸附量明显高于针－赤混合型氧化铁的磷吸附量，并随粘粒中Ｇ／Ｇ（

TYPES OF Fe OXIDES AND THEIR PHOSPHATE SORPTION CHARACTER IN SOILS WITH VARIABLE CHARGE

The types of Fe oxides and their relation to phosphate adsorption or desorption on clay fractions were investigated by means of XRD and chemical analysis methods. Results indicated that the type of Fe oxide was only goethite in yellowbrown soil. The dominant Fe oxide was hematite in latosol and red soil, and was goethite in brown red soil. The MCD values of goethite were generally smaller than those of hematite, but the specific surface areas of the former were greater than those of the latter. The P adsorption of goethite was much greater than that of the mixture of goethite and hematite, and the P adsorption increased with increasing the G/(G+H) value in Fe oxides. The thinner the hematite crystal was, the less the P adsorbed would be. The P adsorbed on goethite was desorbed more difficulty than that on hematite. The difference of hematite morphology hardly influenced the desorbing ratio of P adsorbed by hematite.