Phosphorus Modified Beohmite And Alumina And Their Adsorption Properties For Cd²⁺?Pb²⁺in Aqueous Solution

Beohmite is an inorganic material which has porous structure.And it's an important precursor for preparing activated alumina.Activated alumina is widely applied in industrial wastewater treatment as an adsorbent mainly for removing anions.In this study,aluminum sulfate,sodium metaaluminate and disodium hydrogen phosphate were used to synthesis phosphorus modified beohmites with large BET surface area.Phosphorus modified beohmites have larger BET surface area and lower IEP than beohmite.A sample with Al/P ratio of 25%has an adsorption quantity of 124.6 mg·g-1 for Cd2+ and 237.5 mg·g-1 for Pb2+.The adsorption quantity increases with the decreasing IEP and the adsorption processes were well represented by the pseudo-second-order model kinetics and Langmuir isotherm.Commercial beohmites and disodium hydrogen phosphate were used to synthesis phosphorus modified ?-Al2O3 by equivalent-volume impregnation.Phosphorus modified ?-Al2O3 samples have smaller BET surface area and lower IEP than ?-Al2O3 samples.A sample with Al/P ratio of 20%has an adsorption quantity of 493.7 mg·g-2 for Cd2+.The equilibrium was reached in 4h and the adsorption processes were well represented by the pseudo-second-order model kinetics.