| With the rapid development of livestock breeding industry of our country,the environmental pollution of manure produced by livestock farming is becoming more and more serious.If untreated well and discharged directly it can easily cause eutrophication of water because it contains large amounts of nitrogen and phosphorus elements.Therefore,it is of great significance to remove nitrogen and phosphorus from livestock manure for the prevention and control of water eutrophication.The adsorption method has advantages of high efficiency,simple operation and has no twice pollution,meanwhile,it can be used to recycle nitrogen and phosphorus resources and it is being paid more and more attention by all countries in the world.This study selected the inexpensive Maifan stone as the adsorbent material,in light of the eutrophication pollution problems of Dali Erhai,with the urine of cows as the processing object,we used Maifan stone modified by sodium hydroxide and ferric nitrate to conduct the adsorbent experiment.To explore the best way to modified Maifan stone and the best adsorption condition of static and dynamic adsorption of ammonia nitrogen and phosphorus in wastewater,and characterization analysis of ammonia nitrogen and phosphorus adsorpted by Maifan stone to fit the adsorption isotherm model,to explore the mechanism of the mechanism that Maifan stone adsorpt ammonia nitrogen and phosphorus.The results showed that the adsorption effect of Maifan stone modified by sodium hydroxide and ferric nitrate has increased significantly,dosing 1 g Maifan stone modified by sodium hydroxide at 50 mL simulated water sample,under the condition of pH 6.0,25℃ to adsorpt 4 h;dosing 0.8 g Maifan stone modified by ferric nitrate at 50 mL simulated water sample,under the condition of pH 7.0,25℃ to adsorpt 6 h.The removal rate of ammonia nitrogen and phosphorus from simulated wastewater was up to 86%and 98%.Using Maifan stone to conduct the adsorption treatment of simulated wastewater,the amount of ammonia nitrogen and phosphorus in Maifan stone content were greatly improved,improve the medical stone as application potential of agricultural fertilizer;after the change in the experiment of effect of dynamic factors on the removal of ammonia nitrogen and phosphorus in wastewater by modified bovine urine stone effect has a direct impact.When the column height is 40 cm,the water flow rate was 5 mL/min,the cow urine liquid treatment collected in this experiment,change of nitrogen and phosphorus in wastewater on urinary stone has a good removal effect of Maifan stone.Natural stone and wheat meal before and after adsorption was characterized by BET,XRD,SEM and FT-IR,the results showed that Maifan stone formation of porous structure,ammonia nitrogen and phosphorus in the wastewater effectively adhered on the surface of the stone,and the modification methods and not on the stone of the crystal.The result of analysis of Freundlich adsorption isotherm curve showed that the process of adsorption of ammonia nitrogen and phosphorus by modified Maifan stone is a kind of non-uniform and multi molecular layer adsorption process.Study of the mechanism of Maifan stone adsorption of ammonia nitrogen and phosphorus showed that the adsorption process of modified Maifan stone adsorption of nitrogen and phosphorus could be divided into two steps:first,effective adsorption site of the solution of ammonia nitrogen and phosphorus combined with Maifan stone,and then reacted with the material on the adsorption sites through chemical complexation and ion exchange reaction,and the Na+adsorpted on the pore surface reacted with the NH4+ion to achieve the effect of adsorption of ammonia nitrogen in wastewater,meanwhile,phosphorus and iron oxide hydrate conducted complex reaction,generating compounds such as Fe3(PO4)2,Fe(PO3)3 and Fe(H2PO4)3 compounds to remove the phosphorus of the wastewater.The ammonia and phosphorus was fixed on the surface or channel of Maifan stone to achieve the adsorption effect of ammonia nitrogen and phosphorus in solution. |
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