Study on adsorption properties of free and complex Cd(Ⅱ)in water by modified poplar sawdust
Ethylenediamine tetraacetic anhydride modified poplar dust(EPSD)adsorbent was prepared by solvent method.EPSD was characterized by SEM,FTIR and BET analysis.The adsorption properties of EPSD for citrate/tartrate complexed cadmium were discussed by static and dynamic adsorption experi-ments,and compared with those of free cadmium.The results showed that the surface of poplar bottom was modified by carboxyl group.The optimal pH value of EPSD adsorbing free and complexed Cd(Ⅱ)solution is about 6.0.The adsorption behavior of Cd(Ⅱ)conforms to the pseudo-second-order kinetic model,and the adsorption rate of heavy metal ions is mainly controlled by chemisorption.The Langmuir isotherm mod-el can better describe the adsorption isotherm of Cd(Ⅱ),indicating that the adsorption is monolayer.Thermodynamic analysis shows that all adsorption reactions are spontaneous endothermic processes.With the increase of inlet flow velocity,the time for EPSD to reach the penetration point of the free state and complex state Cd(Ⅱ)is gradually advanced,and the inlet flow velocity of 1.5 mL/min is the most suit-able for dynamic adsorption of EPSD.The adsorption capacity utilization of free Cd(Ⅱ)and tartaric acid complex Cd(Ⅱ)can reach54.93%～68.95%and 53.17%～70.47%,respectively.EPSD has a good application prospect for the adsorption of both free and complex Cd(Ⅱ)in water.
NETL
NSTL
万方数据
