【摘要】 利用膨润土原矿提取了粒径小于2μm的膨润土胶体,经过钠质化处理后分别用聚羟基铁和聚羟基铝进行改性,然后用一次平衡法研究了改性膨润土对水体中铬酸根的吸附性能。结果表明,与原矿相比,改性膨润土对铬酸根的吸附量有了不同程度的提高,铁改性膨润土对铬酸根的吸附量大于铝改性者。CrO42-的吸附平衡浓度为0.5mmol·L-1时,Mt-1(Fe)、Mt-2(Fe)和Mt-3(Al)对铬酸根的吸附量分别为271.0mmol·kg-1、114.0mmol·kg-1和16.1mmol·kg-1。改性膨润土对铬酸根的吸附量随离子强度的增加而增大,随体系pH值的增加而减小。铬酸根在改性膨润土表面的吸附以专性吸附机制为主,静电吸附所占比例很小,一般不超过30%。这些研究结果可为开发新型水处理剂提供理论指导。更多还原

【Abstract】 Clay fraction less than 2μm in diameter was separated from a bentonite collected from Nanjing suburb by decantation and then Fe/Al modified bentonites were prepared from bentonite colloid after it was saturated with Na+ in this study. Adsorption of CrO42-by Fe/Al modified bentonites was investigated with a batch method. The results of our study have shown that a noticeable increase in CrO42-adsorption by Fe modified bentonite than the one modified by Al. When the equilibrium adsorption concentration was 0.5 mmol·L-1, the amount of CrO42-adsorbed by Mt-1（Fe）, Mt-2（Fe） and Mt-3（Al） was 271.0 mmol·kg-1, 114.0 mmol·kg-1 and 16.1 mmol·kg-1, respectively. Since the amount of CrO42-adsorbed by Fe/Al modified bentonites increases with the increase in the ion strength and decreases with the increase of pH, the adsorption of CrO42-may involve specific and electrostatic interaction of CrO42-with the modified bentonites. The specific adsorption can be thought of as the main mechanism for CrO42-under the experimental conditions in this study. The contribution of electrostatic adsorption proves less than 30% of the total adsorption of CrO₄^2-. Thus, the results obtained are expected to provide a useful reference to developing new doses for waste water treatment.更多还原