Study On Adsorption Of Ammonia Nitrogen Wastewater By Ion Exchange Resins

Ammonia is not only a major contaminant in municipal,industrial and agricultural wastewaters,but also a resource.Ammonia treatment methods are mainly biological and physical and chemical methods,the basic principle is to transform ammonia into another form of ammonia.These methods exist in large area,high operating costs,but also resulted in a waste of resources.Therefore,it is urgent to find a low-cost,environmentally-friendly ammonia nitrogen adsorbent to reduce the cost of wastewater treatment and improve the rate of wastewater purification.Adopting self-developed high adsorption capacity of strong acid ion exchange resin treatment of simulated ammonia wastewater in this paper,The effects of resin dosage,pH,reaction temperature,reaction time and initial ammonia concentration on the adsorption of ammonia nitrogen were investigated.The adsorption process of kinetic and thermodynamic mechanisms were analyzed,furthermore,discussing.the dynamic adsorption and analysis process.Static experimental results show that the removal efficiency of ammonia nitrogen increased with the increase of the amount of ion exchange resin;The increase of temperature is beneficial to improve the adsorption efficiency;Resin adsorption of ammonia nitrogen wastewater to achieve a balance of time was 40min;At pH value of 6.5,the adsorption effect of the resin on ammonia nitrogen is the best,then resin static adsorption capacity was 11.05 mg/g;When the solution is Na+>1000mg/L,Ca2+>500mg/L,the resin of the ammonia nitrogen adsorption effect is significantly reduced.The results of dynamic experiments show that the greater the flow rate increased,,the penetration volume decreased,and the the penetration time increased.The greater the concentration of the influent solution was,the smaller of the penetration volume was,and adsorption capacity of the resin increased,the result is consistent with the static experimental results.Adopting 20mL/min flow conditions to remove ammonia nitrogen concentration of 200mg/L simulated ammonia wastewater,The dynamic saturated adsorption capacity of resin to ammonia nitrogen was 86.72mg/g.Adsorption of saturated resin at lOmL/min flow rate,with about 3 times the resin body of 20%NaCl + 0.5%NaOH for analysis can be achieved recycling.The adsorption rate of resin performance changes lessafter ten times continuous adsorption and regeneration.The comparative study of the adsorption of simulated wastewater and industrial wastewater showed that the effect of ammonia nitrogen treatment by the resin on the industrial wastewater was significantly reduced.The analysis of Adsorption Mechanism show that the adsorption of ammonia nitrogen by ion exchange resin is more consistent with the Langmuir adsorption isotherm equation,and the adsorption of ammonium ions is the adsorption of monomolecular layer.The adsorption of ammonia nitrogen on the resin is an endothermic reaction(AH>0),accompanied by the increase of entropy(△S>0),and the adsorption process is spontaneous(AG<0).The process of adsorbing ammonia nitrogen by ion exchange resin is more consistent with quasi two order kinetic model.And the ion exchange resin on the ammonia nitrogen adsorption process is mainly controlled by the liquid film diffusion.Infrared spectrum analysis shows that the resin before and after adsorption of ammonia,the adsorption process of ammonia resin is through H+ and NH4+ active groups on the-SO3H dissociation happened out of the ion exchange.The treatment of ammonia nitrogen wastewater by new strong acid cation exchange resin is a feasible and effective treatment method for ammonia wastewater.