天然膨润土的矿物特性及其磷吸附性能研究

Mineral Characteristics of Natural Bentonite and Its Phosphate Adsorption Properties

比较了不同天然膨润土共7个样品对不同程度磷污染水体的吸附净化性能,通过等温吸附实验,探讨了膨润土对磷的吸附机制。结果发现,供试膨润土对水体磷均有一定的吸附净化潜力,但针对不同程度磷污染水体存在一定差异,且同一属型膨润土的吸附净化能力因矿物组成差异而不同。针对模拟Ⅴ类水(P 0.4 mg/L)和劣Ⅴ类水(P 1.0 mg/L),BN-2的吸附净化能力最强,BN-6的吸附净化能力较差,而其余膨润土对磷的吸附净化能力稍显差异。天然膨润土对磷的吸附等温曲线符合Freundlich方程,说明膨润土对磷的吸附可能属于不均匀介质的多分子层吸附。结果表明,在针对不同程度磷污染水体时,需根据膨润土的矿物特性,使各具特殊性质的不同天然膨润土矿样得到有效的应用。

Phosphate adsorption capacities of different natural bentonites, including seven samples, in phosphate-contaminated waters different in phosphate concentration were investigated, and the mechanism of phosphate adsorption onto bentonite was discussed by adsorption isotherm experiment. Results showed that phosphate adsorption capacities of seven natural bentonitcs were different in waters different in phosphate concentrations, and also did the same genotype bentonite with different mineral constituents. In water of Grade V （P 0.4 mg/L） and Grade V-minus （P 1.0 mg/L）, BN-2 had the highest adsorption capacity, BN-6 had the poorest adsorption capacity, while other bcntonites had great different phosphate removal efficiencies, due to their discrepant composition. The phosphate adsorption isotherm of natural bentonitcs was fitted to the Freundlich equation in terms of R^2 values. It suggested that the adsorption process of phosphate on bentonites was inhomogeneous multilayer adsorption. The results depicted above revealed that different natural bentonites should be choosed in practical application, in view of their characteristics, to make them effectively applied.