Research On Adsorption Capability Of The Clinoptilolite To Ammonia-nitrogen Wastewater With Low Concentration And Regeneration

The urban sewage is a kind of renewable water and reused as reclaimed water by advanced treatment. To strengthen research about urban sewage advanced treatment technology and to develop new technology have important practical significance for sustainable utilization of water resources.In recent years, a new type of adsorbent-clinoptilolite has attracted many research attentions. The clinoptilolite has low cost and good adsorption and ion-exchange properties, especially in removing ammonia nitrogen. The advanced treatment of ammonia-nitrogen wastewater by clinoptilolite has good industrial application value and prospects.In this paper, The simulated ammonia-nitrogen wastewater was studied first. The adsorption capability, the regeneration capability and the influencing factors of the clinoptilolite to ammonia nitrogen are studied through static state test, dynamic test and regenerative test. Then, the disposal of actual wastewater with clinoptilolite and activated carbon is a theoretical basis of practical application in engineering. Specific conclusions were as follows.(1) The clinoptilolite has good adsorption effect of ammonia-nitrogen in wastewater, and it could lowered ammonia-nitrogen levels from8mg/L to1mg/L to meet the Ⅲ standard of GB3838-2002《Surface Water Environment Quality Standard》.(2) Freundlich equation and Langmuir equation could describe the clinoptilolite adsorption behavior of ammonia-nitrogen, but Langmuir equation was better. The McKay false secondary equation is quite fit for expressing adsorption kinetics experiment data.(3) The ammonia nitrogen removal rate increased and the equilibrium adsorption capacity decreased gradually with the increase of clinoptilolite dosing quantity within a certain range. The ammonia nitrogen removal rate increased with the temperature rised. The ammonia nitrogen removal rate was up to75%when pH was6,7,8,9, but it was the largest when pH was near7.(4) The clinoptilolite column adsorption experiment showed that the best adsorption conditions were clinoptilolite with particle size of0.8-1mm and wastewater with flow rate of4m/h. The NaCl modified clinoptilolite has more adsorption ability to ammonia nitrogen than natural clinoptilolite. (5) The clinoptilolite had preferable regeneration effect on conditions of regenerated liquid of0.9mol/L NaCl, regenerated time of5h and regenerated liquid dosage of1:20. The adsorption capacity and regenerated rate of clinoptilolite were1.20mg/g and51.3%indicated that clinoptilolite has good renewability.(6) Clinoptilolite combined with activated carbon could remove COD and ammonia-nitrogen in the actual wastewater effectively.