The Performance And Mechanism For The Removal Of Fluorine And Phosphate From Water By Aluminum-zirconiium Granular Adsorbent

The adsorption method is widely used as a deep water purification process because of its low cost,high efficiency and convenient operation.The key of this technology is to select the appropriate adsorbent material.For water-fluoro(F.),Phosphorus(P)the problem of excessive contamination,the present study developed a new and efficient adsorbent material-Aluminum zirconium composite particles of metal oxides(Aluminium Zirconium Granular Adsorbent,AZGA),The surface physical and chemical properties and structural characteristics of AZGA were studied by means of thermogravimetric analysis,compressive strength test,XRD,BET and Zeta potential analysis.The adsorption characteristics and water quality factors of F and P were discussed by adsorption kinetics,adsorption isotherm,pH effect and coexisting ion influence experiment.The adsorption mechanism of AZGA on F and P was explained by SEM-EDS,Mapping,FTIR,XPS,NMR and Raman.The effects of F / P and regeneration on the adsorbent were evaluated by desorption-regeneration experiments and dynamic column experiments.The main results are as follows:1 ? By comparing the removal efficiencies of F and P with different proportions of aluminum,iron and zirconium adsorbents,the optimum adsorbent was Al: Zr = 3: 1,The AZGA particles with particle size of 2 ~ 2.5mm were prepared by extrusion method with polyvinyl alcohol(PVA)as binder.The surface properties of AZGA particles were characterized by a number of characterization techniques.The maximum mechanical load is34.21 N,the specific surface area is 29.55 m2 / g,the zeta potential is pHpzc = 6.93,the surface of the material contains a large number of hydroxyl groups,the main elements are C,H,O,Al,Zr,S?2 ? The static experimental results of AZGA except F and P show that the dynamic characteristics of AZGA are in accordance with the quasi-second order model,except that the kinetic characteristics of P are in accordance with the Power model,This indicates that the adsorption of F / P occurs on the heterogeneous surface,and the chemical adsorption is the main;The results show that the adsorption rate of AZGA on F and P is affected by more thanone reaction process.At the same time,AZGA is suitable to Freundlich model for F / P adsorption isotherm,which further confirms that adsorption is mainly chemical,and the maximum adsorption capacity of AZGA to F and P is 65.07 mg / g and 20.76 mg / g,respectively.Higher than most other particulate adsorbents.3?The optimum pH value of AZGA was 6.93,except that P was the best pH value of 3,and the anions had the inhibitory effect on the addition of P in the addition of P,The interference effect of PO43-is the largest in addition to F,and the interference effect of SiO32-P is the largest in P,which is mainly due to the competitive adsorption between anions.Ca,Mg and other cations can promote the adsorption of F and P by bridging.4 ? The dynamic and regeneration experiments of AZGA showed that the optimum regeneration concentration was 0.3mol/L NaOH,and the adsorption effect was 71.34% after the fifth cycle.When the column volume reached 808 BV,the effluent F-concentration was0.997 mg / L,and the regeneration column volume reached 704 BV.Compared with the initial adsorption,the column volume decreased by 12.87% and the adsorption capacity decreased by 16.6%.5 ? The dynamic and regeneration experiments of AZGA showed that the optimum regeneration concentration was 0.3mol/L NaOH,and the adsorption effect was only 77.8%after five cycles of regeneration.When the column volume reached,the column volume of the effluent P was more than 584 BV and 780 BV,respectively,and the volume of the column after dynamic regeneration was 504 BV and 636 BV respectively.After the column was regenerated,the column volume was reduced by 18.5% and the adsorption capacity decreased by 23.7%.6?The samples were analyzed by SEM-EDS,Mapping,FTIR,XPS,NMR,Raman and so on.The results showed that AZGA was mainly composed of rich hydroxyl groups and F,P,And the surface of AZGA embedded in the SO42-ion exchange reaction.