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采用不同添加量(1~4 mmol/g)的聚合羟基铝离子(Al13)柱撑改性膨润土,制得系列铝柱撑膨润土(Al13-Bent)。采用X射线衍射、热分析、N2吸脱附比表面积分析等表征分析了其结构特点,比较了不同添加量Al13-Bent对水中磷酸根与结晶紫的吸附性能。结果显示,随着Al添加量增大,Al13-Bent的比表面积增大,柱撑产物的底面间距在添加量为2 mmol/g后达到最大,稳定于1.9 nm左右。Al13-Bent对水中磷酸根的吸附效果好于原始膨润土,且随着Al含量增加而提高。Al13-Bent在低Al添加量下对水中结晶紫虽有较好的吸附能力,但其吸附性能相比于膨润土原土却有所下降。就其吸附机理来看,层间域内Al13离子表面羟基与层间阴离子促进了对阴离子含氧酸根的吸附;由于Al13柱撑后,层间可交换阳离子减少,导致对阳离子型染料的吸附性能下降。
A series of aluminum-pillared bentonites (Al13-Bent) were prepared by pillared modification of bentonite with different concentrations of Al (1 ~ 4 mmol / g). The structure and properties of Al13-Bent were investigated by X-ray diffraction, thermal analysis and N2 adsorption-desorption ratio surface area analysis. The adsorption properties of phosphate and crystal violet in water were compared. The results showed that with the increase of Al content, the specific surface area of Al13-Bent increased, and the distance between the bottom of pillared products reached the maximum at 2 mmol / g and stabilized at 1.9 nm. Al13-Bent adsorbed phosphate in water better than the original bentonite and increased with increasing Al content. Al13-Bent has good adsorption ability to crystal violet in water at low Al addition, but the adsorption capacity of Al13-Bent is lower than that of bentonite. In terms of its adsorption mechanism, the hydroxyl groups and interlayer anions on the surface of Al13 ions in the interlayer region promote the adsorption of anionic oxo acid radicals. Due to the reduction of the exchangeable cations between layers due to the Al13 pillaring, the adsorption performance on the cationic dyes decreases .