Study On The Adsorption Of Fluoride With The Modified Activated Alumina

In Recent,people are increasingly concerned about hazards of fluoride,and because of the existence of fluorine widely in minerals, drinking water in many areas are containing high fluoride。Also, Because Chinese industrial production is becoming more and more widespread,many factories,which produce electronic products, fertilizers, materials and so on,discharge waste water containing high concentrations of fluoride,the adsorption of fluoride ion removal is imminent。Alumina adsorption of fluoride is the world recognized the best technology。With the continuously go deep into the study of alumina adsorbent,this study has obtained better results。Under this condition, this paper studies the adsorption properties of modified alumina heap.In this paper, the use of modified alumina is load the rare earth elements manganese into alumina to get Mn-Al2O3,and research on the Mn- Al2O3 adsorption performance of fluorine ion。Under different pH,this paper studies Mn-Al2O3 adsorbing fluoride ion。The Experiment Result Indicates that:When the pH is 4, the adsorption effect is best;In different temperature and initial concentration, which the best conditions is 20 ℃and the initial concentration of 9.5 mg/L,Fluoride ion removal rate is highest, that is 76.84%。In the adsorption isotherm experiments, the experimental data that both Langmuir and Freundlich equation were fitted,the Experiment Result Indicates that:Mn-Al2O3 adsorption of fluoride ion in line with the adsorption isotherm fitting and Langmuir isotherm fitting。When the temperature is 25 ℃, the fitting curve has a good relationship(R=0.993)。When the temperature is 25℃、30℃,Freundlich isotherm model fitted curve has a relationship,the correlation coefficient is 0.946 and 0.951,which show that Mn- Al2O3 conform to the secondary adsorption isotherm equation fittingIn the adsorption kinetics experiments,Mn- Al2O3 adsorb fluorine ion with different times and different initial concentration。the Experiment Result Indicates that:When the initial concentration is 9.5 mg/L,19 mg/L, and the adsorption time is 10 min, Adsorbent for the absorption of fluorine ion is in balance;When the initial concentration is 28.5 mg/L,and the adsorption time is 12 min,,Adsorbent for the absorption of fluorine ion is in balance。The use of adsorption kinetics model fitting, secondary fitting according to the results,When the initial concentration is 9.5 mg/L and 28.5 mg/L,the correlation coefficient is 0.959 and 0.943,which means the preparation of Mn- Al2O3 material conform to the secondary dynamics equation。On the analysis of the removal rate of fluorine ion results show that:When to reach adsorption equilibrium, removal rate of 60.95%, 50.16% and 49.14% respectively.