Preparation Of Zeolite And Fly Ash Modified Materials And Their Removal Performance Of Ammonia Nitrogen And Phosphorus In Water

Water eutrophication is one of the most eye-catching water environmental problems in the world.The main reason is that the excessive accumulation of nutrients such as nitrogen and phosphorus in water bodies leads to the proliferation of phytoplankton.It is generally believed that reducing the nitrogen and phosphorus concentrations in the water and inhibiting the release of endogenous nitrogen and phosphorus from the sediment are effective ways to effectively control eutrophication on the basis of controlling the input of external sources of pollution.In this paper,natural zeolite and fly ash were used as raw materials.A porous adsorbent was prepared by secondary modification of alkali,salt modification and high temperature calcination.The modified oxygen carrier was modified by pressure swing adsorption to obtain a new composite functional material.The goal of this study is to develop a new composite functional material with high efficiency of ammonia nitrogen and phosphorus adsorption and strong oxygen carrying capacity,and to apply it in situ in the field and in the field to achieve the concentration of ammonia nitrogen and phosphorus in eutrophic water.Reduce,at the same time repair the bottom anaerobic environment,reverse the redox conditions,effectively control the risk of secondary release of endogenous pollutants into the water.Studies have shown that by alkali and salt modification,the surface of the material is loaded with cations,which increases the ability to adsorb nitrogen and phosphorus.The high temperature calcination modification effectively increases the specific surface area and porosity of the material,increases the oxygen carrying capacity of the material,and pressure swing adsorption.Oxygen loading is a composite function of the material to form"adsorption+oxygen carrying".The main results are as follows:(1)In this experiment,the optimal preparation conditions of material ZFA were determined by orthogonal test:m(zeolite):m(fly ash)=3:2,calcination temperature 800?,calcination time 150 min,heating rate 10?/min.The intensities of the four influencing factors are:calcination time>calcination temperature>m(zeolite):m(fly ash)>heating rate.(2)The optimal salt-alkali modification conditions were determined by screening:the concentration of sodium hydroxide solution and aluminum chloride solution were 1 mol/L and 1 mol/L,the modification time was 24 h,and the solid-liquid ratio was 1:6.(3)The modified MZFA has a specific surface area of 52.86 m2/g and is mainly mesoporous.Compared with the original material,the modified MZFA is loaded with sodium and aluminum.(4)In order to better verify the experimental data,Langmuir and Freundlich adsorption isotherms were used to fit the results.The results show that the adsorption process of ammonia nitrogen and phosphorus by MZFA accords with the Langmuir adsorption isotherm model,and the adsorbent interacts with the adsorbate during the adsorption process.(5)Through the practical application of the Houhu Lake in the Summer Palace in Beijing,it is proved that the application of MZFA composite functional materials to the sediment-water interface can effectively improve the oxygen environment at the sediment-water interface and inhibit the release of phosphorus from the sediment into the water.Improve the eutrophication of water bodies.