白云石质凹凸棒石粘土的磷吸附特性及应用浅析

CHARACTERIZATION AND MECHANISM OF PHOSPHATE ADSORPTION ONTO DOLOMITIC ATTAPULGITE

选择江苏省盱眙雍小山和仇集黄泥山的白云石质凹凸棒石粘土,以凹凸棒石粘土和白云石为对照,比较它们对磷的吸附特性,在分析吸附性能的基础上阐明白云石质凹凸棒石粘土对磷的吸附机理。结果发现,白云石质凹凸棒石粘土对磷的吸附性能显著优于凹凸棒石粘土,在低磷污染水体中,其对磷的吸附净化能力与活性炭接近,吸附等温曲线呈S型,且Freundlich方程拟合效果更好,说明白云石质凹凸棒石粘土对磷的吸附可能属于不均匀介质的多分子层吸附。此外,白云石质凹凸棒石粘土与同比例凹凸棒石粘土/白云石复混材料的磷吸附能力相当,而两者均高于单独凹凸棒石粘土与白云石的比例加和。结果表明,白云石质凹凸棒石粘土具有较佳的磷吸附能力,可用作磷污染水体的吸附净化材料。

Dolomitic attapulgite was selected to compare its phosphate adsorption characteristics with dolomite and attapulgite, and then its adsorption mechanism was clarified on the basis for the analysis of phosphate adsorption properties. The results showed that dolomitie attapulgite had better phosphate adsorption capacity than that of attapulgite,which was close to activated carbon in wastewater with low phosphate concentration. The phosphate adsorption isotherm of dolomitic attapulgite is an S-type isotherm, and the Freundlich equation provided better fitting than the Langmuir equation in terms of adsorption parameters. It is suggested that the adsorption of phos- phate on attapulgite was inhomogeneous multilayer adsorption. In addition,the phosphate adsorption capacity of dolomitic attapulgite was approximately the same as the attapulgite/dolomite complex mixture with the same proportion of dolomite, while both were higher than the total phosphate adsorption results calculated from individual attapulgite and dolomite. The results above revealed that dolomitic attapulgite had better phosphorus adsorption capacity and it could be used as adsorption purification materials in phosphate-polluted water bodies.