Research And Industrial Application Of Renewable Material On Ammonium Removal

Ammonia nitrogen is one of the main pollutants in municipal wastewater,and the nitrogen content is generally lower than 50ppm,which belongs to low concentration ammonia nitrogen pollution.Ammonia nitrogen is the culprit of water eutrophication,and under the action of ammonia oxidizing bacteria,it can generate NO2-N,causing great harm to human beings.Therefore,ammonia nitrogen in wastewater is an urgent problem to be solved.In this paper,according to the physical and chemical properties of ammonia nitrogen,we explored a series of new methods of ammonia separation.The results showed that the surface hydrogen bond and pore size could not effectively separate ammonia nitrogen.We choosed the method of ion exchange and chemical precipitation to remove ammonia nitrogen.The original powder of magnesium aluminum phosphate molecular sieve was synthesized by hydrothermal method through phosphorus source,aluminum source,magnesium source and templating agent.After calcination at 550 ?,aluminum magnesium phosphate molecular sieve was obtained.And this material can adsorpt 1.6mg/g of ammonia nitrogen,but it is the difficult to regenerate and hard to recycle use.And then we developed a series of silica-alumina molecular sieves with a high adsorption capacity and easy regeneration.Through the optimization of the silicon source,aluminum source,alkali source and template materials,and adjusting of the amount of alkali?silicon?aluminum?hydrothermal time and water temperature,we obtained a silica-alumina molecular sieve material with high specific surface area and high adsorption capacity.And its adsorpt capacity of ammonia nitrogen can reach 22mg/g.It can be completely regenerated with a certain concentration of sodium chloride solution,and the regeneration performance is relatively stable.In order to avoid the blockage and the loss of powder in the process of application,we studied the molding of the material.Two kinds of molding formulations were studied,one mothed is using water glass as a binder and glucose as a pore forming agent,the other is using PAN as a binder and DMF as solvent,with the mechanism of phase transformation dropping molding.Through the small scale experiment of the adsorption column,the molecular sieve was in good condition.It showed a high adsorption capacity of ammonia nitrogen in the sewage.Moreover,the ammonium ion belongs to the dominant ion,which shows a certain selectivity.After the simulation calculation,the cost of treating 1m3 wastewater with zeolite is only 0.39 RMB.