Experimental Study On Treatment Of Ammonia Nitrogen In Micro-Polluted Water By Zeolite And Modified

With the continuous expansion of the city and the rapid economic development,the discharge of industrial wastewater,domestic sewage and excessive use of chemical fertilizers and pesticides have caused varying degrees of pollution to the Pearl River.Over the years,relevant departments of A southern city have always been committed to the pollution control in the Pearl River.However,the pollution indicators such as ammonia nitrogen in water bodies are still high and the water quality changes greatly.This has plagued the water supply treatment and posed a potential hazard to residents' safe drinking water and health.In this paper the Pearl slightly polluted raw water for the study,in order to remove the effect of ammonia in water polluted water Micro Pearl index control,using zeolites and modified zeolite for adsorbing ammonia solution to the problem ammonia concentration in source water slightly polluted Pearl excessive.Adopting the static adsorption method,the effects of the factors such as particle size,dosage,pH value and temperature on the adsorption of ammonia nitrogen in the micro-polluted source water by zeolites and modified zeolites were investigated.The effects of the type,concentration,solid-effect effect,respectively,and determine the optimum reaction conditions by orthogonal test;The relationship between the microstructure of zeolite and adsorption of ammonia nitrogen was analyzed by scanning electron microscope(SEM),specific surface area and chemical composition.Research zeolite and modified zeolite adsorption thermodynamics and kinetics and other issues,and provide reliable test data and scientific technical support for future combined process productivity test.Effects of zeolite particle size,dosage,pH,temperature and other factors on the removal of ammonia nitrogen in the slightly polluted source water of the Pearl River were studied.The results show that the optimal particle size of natural zeolite and modified zeolite is 60-75 meshes and the optimum pH is 6-9.The lower the water temperature is,the higher the removal rate of ammonia nitrogen from zeolite is,and the best dosage of natural zeolite the optimum dosage of modified zeolite is 6.4g/L when the amount of modified zeolite is 8g/L.When the modified zeolite is used to treat the ammonia nitrogen in the slightly polluted water,the dosage of zeolite is saved by 20%.Orthogonal Experiment Study on Optimum Reaction Conditions for Adsorbing Ammonia and Nitrogen by Zeolite in Pearl River Micro-polluted Source Water.Test results:The order of influence of various factors on zeolite adsorption of ammonia nitrogen is:zeolite particle size>adsorption time>dosage>temperature>pH value.The optimum particle size of natural zeolite and modified zeolite is 60-75 mesh,the adsorption time is 30min,the temperature is 30 ?,the optimum pH is 9,and the dosage of modified zeolite is less than natural zeolite.The effects of regenerant type,concentration,regeneration time,pH and other factors on regeneration of saturated zeolite were studied.The results showed that the best regeneration solution was 1mol/L KCl solution and the regeneration time was 40min.When the solution pH value was less than 10,the regeneration effect was small,and the desorption amount was about 4.34?4.67mg/g.Orthogonal experimental study of optimal conditions for the regeneration of saturated zeolite.Test Results:The order of influence of various factors on regenerated saturated zeolite is:solid-liquid ratio>regenerant solution type>pH value>regeneration time.Regeneration liquid species lmol/L KCl solution,regeneration time was 40min,PH value of 7.Under the optimum reaction conditions,the regenerated zeolite repeatedly adsorbed NH3-N in the micro-polluted source water of the Pearl River.At the second and third repeated adsorption,the adsorption amount weakened by 24.8%and 31.2%respectively.The relationship between zeolite micro structure and adsorption of ammonia nitrogen was observed and studied.The results showed that zeolite with flake distribution adsorbed ammonia nitrogen more effectively than granular zeolite,zeolite with compact structure,uniform pore distribution and uniform pore size had better ammonia nitrogen adsorption effect.Compared with Zhejiang Jinyun zeolite of 10-18 mesh size,Zhejiang Jinyun zeolite of 60-75 mesh showed strong permeability and large pore size,and the adsorption effect on ammonia nitrogen increased by 84.78%,which is favorable for the removal of ammonia nitrogen.Large surface area of the zeolite adsorption of ammonia nitrogen effect;The average adsorption pore size of zeolite is closer to that of NH4 +,and the adsorption effect is better.The silica-alumina ratio greater than 8 high silica zeolite adsorption of ammonia nitrogen is good,clinoptilolite Bili serpentinite asbestos adsorption effect.Experimental study of zeolite adsorption thermodynamics and kinetics and other issues.The results show that the Langmuir isotherm equation of natural zeolite for the adsorption of ammonia nitrogen is y = 0.5722x + 0.1499,and the R2 correlation is high,which means the adsorption of ammonia nitrogen by natural zeolite is monolayer adsorption.The Freundlich isotherm equation for the adsorption of ammonia nitrogen on the modified zeolite is y= 0.4352x+ 0.4607,and the correlation of R2 is high,indicating that adsorption of ammonia nitrogen by the modified zeolite is multi-molecular layer adsorption.The Lagergren quasi-second-order kinetic equations for the adsorption of armmonia-nitrogen on natural zeolite and modified zeolite are t/q = 0.0934t + 0.9093 and t/q= 0.0676t + 0.3204,respectively.The quasi-second-order kinetic equation has a higher R2 correlation,A more accurate description of zeolite adsorption kinetics of ammonia nitrogen process.Zeolite adsorption of ammonia nitrogen spontaneous exothermic reaction,the adsorption process is the entropy reduction reaction.Natural zeolite and modified zeolite adsorption of ammonia is a multi-step control process.