Experimental Study on Phosphorus Removal by Modified Activated Alumina

In order to improve activated alumina's performance of phosphorus removal in waste water,the activated alumina as a carrier was modified with aluminum sulfate solution by impregnation method.Pore volume,average pore size and BET surface area were determined.The effects of adsorption time,pH,initial concentration of wastewater,modified dosage and other factors on the phosphorus removal from wastewater were studied.Modified activated alumina's adsorption mechanism of phosphorus was discussed.The results showed that the specific surface area of modified activated alumina was 398.364 m2/g and was improved by 14.22% than the unmodified activated alumina's.The adsorption equilibrium came after four hours and the adsorption capacity of phosphorus improved by 30.4%.The best adsorption pH was 5~7.It was also found that with the increase of initial concentration of wastewater,the removal rate of phosphorus decreased instead,while the removal rate of phosphorus increased with the increasing modified dosage,the optimal dosage of modified activated alumina was 3.0 g/L.Both Freundlich and Langmuir model of adsorption isotherms could reflect the adsorption behavior of modified activated alumina for phosphorus,while the Langmuir model was more proper.