The Defluoridation And Regeneration Performance Study Of Modified Activated Alumina

However, because of the influence of geological structure, hydrogeochemistryand Formation of geotechnical, Groundwater exploitation will has the problem ofexcessive fluoride, arsenic and iron ions. In order to meet the water quality parametersrequirements of different uses, in water treatment,the request of defluoridation isobjective and outstanding.Small regional water often use activated alumina fluoride removal method, buthas the problem of poor adsorption effect and low regeneration rate. This experimentin the same kind of alumina surface coating calcium magnesium. Through the contrasttest studied the effect of the fluoride adsorption capacity and mechanism ofmodificated alumina. At the same time analysised the effect of different regenerationmethods.By dynamic test, studied the influence of fluorine ion removal process,such asadsorption column height，raw water concentration and flow rate.The results show that:（1）The XRD analysis revealed that the main surfacecompositionof three alumina was calibrated as γ-Al2O3. The SEM showed that the sizeand number of surface pore and grain shape were difference each other.The XPSrevealed that the surface of alumina coated with CaO and MgO. Through BET analysisproved that Modification increased the specific surface area of the alumina. Specificsurface area of the modified calcium and magnesium than unmodified increases morethan30%.The batch fluoride adsorption experiments results revealed that the effect offluoride sorption by calcium oxide and magnesium oxide coated activated aluminawas better, and the regeneration is better too.（2）The regeneration effect of differentregenerant is quite different, the effect of regenerated by0.25mol/L sodium hydroxide solution is the best.（3）Dynamic experiments show that，under the sameconditions，the effective running time of Ca-AA and Mg-AA both longer than AA.the effect of fluoride sorption and regeneration is better than AA too. And waterconcentration is direct proportional to the adsorption column height, inverselyproportional to the raw water concentration and flow rate...