摘要
采用不同种类盐对天然沸石进行改性,通过吸附动力学和吸附热力学特性对比,探讨了盐改性方法对沸石吸附生活污水中氨氮性能的影响.结果表明,NaCl、CH3COONa、KCl、MgCl2和CaCl2改性沸石分别在改性液浓度为0.2、0.6、0.4、0.2 mol/L和0.1 mol/L时达到最佳氨氮去除率,分别为95.9％、82.1％、75.4％、74.9％和78.4％,最高达天然沸石的1.3倍,改性成本仅为0.052元/t.天然沸石和盐改性沸石对的吸附可以用准二级动力学描述,适用Freundlich吸附等温模型,低温有利于反应的发生.盐改性增大了沸石的吸附速率、表面均质性和最大离子交换容量.
Abstract
Different types of salts were used to modify natural zeolites,and the performance of zeolites after modification was compared for the adsorption of ammonia nitrogen of domestic wastewater according to the comparison of adsorption kinetics and thermodynamics.The results showed that the best ammonia nitrogen removal effect was achieved at the concentration of 0.2,0.6,0.4,0.2 mol/L,and 0.1 mol/L of the modified solution for NaCl,CH3COONa,KC1,MgCl2,and CaCl2 modified zeolites,corresponding to removal efficiencies of 95.9％,82.1％,75.4％,74.9％,and 78.4％,respectively.The cost to achieve the best salt modification effect(1.3 times the efficiency of natural zeolite)was only 0.052 yuan/t.The adsorption of ammonia nitrogen by natural or salt modified zeolites is consistent with the pseudo-second-order model and Freundlich adsorption isotherm model,and low temperature is favorable for the reaction.The adsorption rate,the homogeneity nature of the surface and maximum ion exchange capacity of zeolite are increased by salt modification.
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