Experimental Study On Adsorption Of Nitrogen And Phosphorus In Water By Modified Zeolite

In recent years,with the rapid development of urbanization and industrialization in China,the problem of water pollution is becoming more and more serious.A lot of wastewater with high nitrogen and phosphorus content is discharged into natural waters,which seriously pollute the water environment and affect the life of human beings.Therefore,more and more scholars have done a lot of researches on highly efficient removal of pollutants from water.Some scholars have found that zeolite has obvious adsorption effect on nitrogen and phosphorus in wastewater,and has attracted more and more attention.The crystal structure of zeolite is unique,which has certain adsorption performance,but the adsorption capacity of natural zeolite is not ideal,so this test is intended by physical or chemical methods of modification test of zeolite increases the specific surface area and cation exchange capacity,and improve the adsorption properties of zeolite.According to the adsorption properties of natural zeolite for ammonia nitrogen and phosphate,the Langmuir and Freundlich isotherms were plotted,and the kinetics of nitrogen and phosphorus adsorption by natural zeolite was studied.The results of the test are as follows:The fitting equation of Langmuir and Freundlich has good fitting effect on ammonia nitrogen adsorption.The fitting correlation coefficients are all greater than0.97,indicating that zeolite adsorption on ammonia nitrogen is a process of physical adsorption and chemical adsorption coexist.In the Freundlich equation,1/n is 0.423,indicating that zeolite has strong adsorption capacity for ammonia nitrogen.The adsorption process of natural zeolite is more consistent with the Freundlich isothermal adsorption model.In the Freundlich equation,the 1/n is 1.233,indicating that adsorption is difficult.The kinetic test results showed that the adsorption process of natural zeolite on nitrogen and phosphorus accorded with pseudo two stage kinetics fitting equation,and its change trend basically accorded with the characteristics of "fast adsorption and slow balance".Take hydrochloric acid modified,modified sodium hydroxide,sodium chloride modification,roasting and composite modification zeolite adsorption test ofwastewater containing ammonia nitrogen;lanthanum modified,modified zirconium and compound modification treatment of phosphorus containing wastewater,zeolite test showed that hydrochloric acid modified and sodium hydroxide modified zeolite adsorption can hardly improve the ability ammonia nitrogen.Sodium chloride modification and calcination modification under suitable conditions can greatly improve the adsorption effect of ammonia composite modified zeolite can improve the adsorption performance of ammonia nitrogen;sodium chloride concentration is5%,calcination temperature is 400 ? composite modified zeolite prepared,the ammonia nitrogen removal rate can reach 74.2%.The removal of phosphorus from water samples by natural zeolite is only about10%.Lanthanum and zirconium modified zeolite can greatly improve the ability of zeolite to adsorb phosphorus,which are 75.5% and 74.4% respectively,and the effect of phosphorus modification is better.When lanthanum modified zeolite is treated at high temperature,the phosphorus removal rate can be further increased,and the phosphorus removal rate is 86%.