Preparation Of Modified Zeolite And Study On Its Removal Efficiency Of Ammonia Nitrogen In Source Water

Water source pollution has always been a major environmental problem facing my country.During the "Twelfth Five-Year Plan" and "Thirteenth Five-Year Plan" period,through the national and local implementation of water source protection and restoration measures,my countrys water source water quality has been improved to a certain extent,but it still exists.Pollution problems of varying degrees.Due to its special climatic conditions,the Northeast region will produce seasonal ammonia nitrogen pollution.It is difficult to deal with this fluctuating ammonia nitrogen pollution only by the conventional treatment process of the northern water plant,especially in the low temperature environment in winter.The removal rate will be lower.As an efficient and economical technology,the adsorption method has been widely used in water supply treatment.Combining the above problems,this topic aims at the problem of ammonia nitrogen pollution in water source water in northern China.It uses artificial zeolite as a raw material for surface modification to improve the adsorption efficiency of zeolite for ammonia nitrogen.It is used in the pretreatment process of water source water to solve the problem of ammonia nitrogen removal under low temperature conditions.problem.Through static and dynamic experiments,it is proved that the zeolite modified by dodecyl sulfonic acid(SDS)can greatly improve the adsorption efficiency of ammonia nitrogen,and can remove the ammonia nitrogen in the source water in a low temperature environment.Different kinds of modifiers are used to modify the surface of the zeolite,and the modification conditions are optimized to obtain the modified zeolite with the best ammonia nitrogen adsorption effect.In the experiment,the removal rate of ammonia nitrogen was used as an evaluation index,and the optimized preparation of modified zeolite was completed,and analyzed by scanning electron microscopy energy spectrum analysis(SEM-EDS),X-ray diffraction spectrum analysis(XRD),nitrogen adsorptiondesorption test and analysis(BET test),to characterize the zeolite before and after modification.The results showed that a solution of sodium dodecyl sulfonate(SDS)with a p H of 7 and a concentration of 6g/L was used to add zeolite at a solid-to-liquid ratio of1:50,and at an oscillation speed of 200r/min,in a constant temperature shaking box The modified zeolite was modified by medium oscillation for 24 hours,and the removal rate of ammonia nitrogen with a concentration of 5 mg/L could reach more than 75%,and the spatial structure of the zeolite was unchanged before and after the modification.Through static experiments,the ammonia nitrogen adsorption efficiency of the modified zeolite was studied,the relationship between different influencing factors and adsorption efficiency was determined,and the best reaction conditions were obtained.The experiment explored the changes in the ammonia nitrogen adsorption efficiency of the modified zeolite by changing the reaction conditions and preparing water samples with interference factors,and carried out a simulation experiment through a dynamic experimental device.The results show that the removal rate of modified zeolite can be as high as 80% in a low-concentration water sample with a p H of 6-9,a solution concentration of 4 mg/L,and a temperature of 20°C.When the input amount is 8 g/L,the removal rate can be as high as 80%.Let the ammonia nitrogen reach the surface water quality standard of Class III.The modified zeolite also has an adsorption effect on iron ions and humic acid in the actual water sample.On the whole,the two interference factors do not affect the final ammonia nitrogen removal rate.Dynamic simulation experiments confirmed that this type of modified zeolite has a better removal effect on this type of low-concentration ammonia nitrogen source water,and the removal rate is inversely proportional to the flow rate.Different adsorption models were used to curve-fit the process of ammonia nitrogen adsorption by modified zeolite,and the mechanism of ammonia nitrogen adsorption by modified zeolite was revealed.Through kinetics and thermodynamics experiments,Langmuir and Freundlich adsorption isotherm models,Lagergrende quasi-one and twostage kinetic models,diffusion control models,and thermodynamic models are used for curve fitting.The results prove that the process of adsorbing ammonia nitrogen by modified zeolite is a spontaneous endothermic reaction process,and the adsorption process is controlled by both intra-particle diffusion and liquid membrane diffusion.The entire adsorption process is mainly chemical adsorption,and physical adsorption is supplementary hybrid adsorption process.