Effect of NaCl modification on ammonia-nitrogen adsorption property of zeolite

Natural zeolite was modified by NaCl solution and the effects of NaCl concentration,temperature and zeolite dosage on modification were studied.In addition,ammonia-nitrogen adsorption properties of natural and NaCl modified zeolite were compared through surface characteristics analysis,static adsorption and dynamical experiments.When 15 g of zeolite was modified in 100 mL of NaCl solution(mass ratio was 6%) at 303 K,the obtained zeolite presented the best ammonia-nitrogen adsorption property.SEM and BET analysis showed that the modified zeolite had rougher surface,smaller average adsorption pore size and larger specific surface area compared with natural zeolite.The adsorption of ammonia-nitrogen on two kinds of zeolite could be well fitted by both Langmuir and Freundlich isotherms equation,and NaCl modification could increase the theoretical maximum adsorption capacities(qm) by 34% or more.The intra-particle diffusion was the limiting factor for ammonia-nitrogen adsorption.The dynamic adsorption data were well described by pseudo second order reaction rate model,and the results indicated that adsorption of ammonia-nitrogen on modified zeolite was better than that on natural zeolite in view point of capacities and velocities.