Effect of Salt Modification Method on Performance of Ammonia Nitrogen Adsorption by Zeolite
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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