In order to explore the adsorption mechanism and optimal regeneration method of natural heulandite to high ammo-nia nitrogen wastewater,the natural heulandite from Hebei Province is selected as the research object.The adsorption kinetics, adsorption isotherms and adsorption thermodynamics are studied by single factor test.The results show that the adsorption process of ammonia nitrogen on heulandite with particle size range of 50～600 μm complies with the quasi-second order kinetic equation with ammonia nitrogen concentration of 500 mg/L at temperature of 25 ℃.Particle diffusion and liquid film diffusion are the dominated process of the adsorption.The adsorption capacity of heulandite is 7.81 mg/g at temperature of 45 ℃.The adsorption isotherm of ammonia nitrogen on the experimental heulandite is fitted well with Freundlich model.Gibbs free energyΔG is calculated to be less than zero,indicating that the adsorption of ammonia nitrogen on the experimental heulandite is a spontaneous endothermic reaction.Additionally,the adsorption capacity of heulandite increases with appropriate increaseing in temperature.The optimal regeneration solvent of the saturated heulandite is 0.1 mol/L of NaCl,with which the desorption rate increases to 79％,and the times of elution and regeneration are more than 5.The results of this study can improve the economic benefits and environmental value of heulandite in the treatment of ammonia nitrogen wastewater.It can be seen that heulandite in the industrial wastewater treatment has broad prospects for application.%为了探索天然片沸石对高氨氮废水的吸附机理及最佳再生方法,选取河北省天然片沸石为研究对象,采用单因素试验法,通过吸附动力学、吸附等温线、吸附热力学进行研究.结果表明,在温度25℃下,粒径为50～600μm,氨氮质量浓度为500 mg/L时,准二级动力学方程更能准确地描述片沸石对氨氮的吸附过程,颗粒内扩散和液膜扩散在吸附过程中占主导地位;当温度为45℃,片沸石的饱和吸附量为7.81 mg/g,吸附等温试验较符合Freundlich模型.吉布斯自由能 ΔG<0,吸附是自发的吸热反应,适当升高温度可提高片沸石的吸附量.对饱和片沸石的最佳再生溶剂为0.1 mol/L的NaCl溶液,解吸率为79％,且可多次洗脱再生.研究结果有助于进一步提高片沸石在氨氮废水处理中的经济效益和环境价值,使得沸石在工业废水处理中的应用前景更加广阔.
展开▼
