Study On The Purification Of Phenol And Ammonia Nitrogen In Wastewater By Modified Potassium Feldspar

In this paper,potassium feldspar（YK）was modified by loa d,and its performance in removing phenol and ammonia nitrogen in wastewater was investigated from the following aspects:1.The modification methods of potassium feldspar were screened.The study shows that Ca（OH）₂ and Na₂SiO₃ load potassium feldspar through hydration,and the adsorption effect of HK on ammonia nitrogen was better.Cetyltrimethylammonium bromide was used to modify the load of potassium feldspar（CaO and Na₂SiO₃）.and the adsorption effect of CK on phenol was good.2.Taking potassium feldspar as raw material,calcium oxide and sodium silicate were used to load it first to make it have more micromesoporous structure,then cetyltrimethylammonium bromide was used to modify it,and the synthesized potassium feldspar load modifier CK was used to investigate the adsorption of phenol in wastewater.Combined with single factor and orthogonal experiments,the optimal preparation conditions for CK were as follows:mass ratio of YK to CaO was 1:0.3,mass fraction of Na₂SiO₃ was 6%,mass concentration of CTMAB was 1.1%,and stirring time of CTMAB was 1h.SEM,XRD,FTIR,BET and EDS mapping were used to characterize the changes of morphology,structure and composition of potassium feldspar before and after modification.The characterization results showed that potassium feldspar had been successfully modified by loading.3.The effects of CK addition amount,initial p H value of solution,adsorption time and initial concentration of phenol on the adsorption of phenol by CK were investigated.The adsorption effect is better when the solution is neutral.Adsorption tends to equi li br ium a t 1h.Wi t h t he i ncr ea se of i nit ial phenol concent r ati on(50～3000 mg·L^-1),the adsorption capacity of CK on phenol increased to 30.64 mg·g^-1 and tended to saturation,which was more than 8.9 times of the raw material.The adsorption mechanism was explored by fitting the kinetic,thermodynamic and isothermal adsorption models.The quasi-second order kinetic model and Freundlich isothermal adsorption model can describe the adsorption process of CK on phenol.The R_L and N values of Langmuir and Freundlich isothermal adsorption models were all within a reasonable range,indicating that the load modification of potassium feldspar was beneficial to the adsorption of phenol in wastewater.△H<0,△G<0,?S<0.Combined with the results of the kinetic model,it can be seen that the adsorption process is a spontaneous entropy reduction and heat release process with the coexistence of physical and chemical adsorption.4.Potassium feldspar was loaded with calcium hydroxide and sodium silicate under the following conditions:the mass ratio of YK to Ca（OH）₂ was 1:0.4,and the total mass fraction of Na₂SiO₃ was 5%.SEM,FTIR and EDS were used to characterize the changes of materials before and after the load.Analysis showed that the potassium feldspar load HK synthesized by hydration had porous structure,increased specific surface area,and had good adsorption effect on ammonia nitrogen in wastewater.The static adsorption experiment of HK on ammonia nitrogen in wastewater was conducted,and the adsorption mechanism was explored by means of kinetic and isothermal adsorption model fitting.The results showed that when the adsorption time reached 6 h,the adsorption tended to be saturated.With the increase of the initial concentration of ammonia nitrogen(100-1000 mg·L^-1),the adsorption capacity of HK to ammonia nitrogen also increased,and the maximum adsorption capacity could reach 9.18 mg·g^-1.The quasi-second-order kinetic model and the Freundlich isothermal adsorption model can better describe the adsorption process,and the allocation factor R _L in the Langmuir isothermal adsorption model is between 0 and 1,and the n in the Freundlich isothermal adsorption model is between 1 and 2,both of which can indicate that the loaded potassium feldspar is more likely to absorb ammonia nitrogen in the wastewater.