논문 상세보기
pp.325-333
This research investigated the feasibility of rice husk as a biosorbent for the removal of heavy metals from aqueous solutions. The carboxyl groups were chemically bound to the surface of the rice husk by graft polymerization of acrylic acid using potassium peroxydisulphate as a redox initiator. The Pb sorption capacity and FT-IR spectra confirmed the presence of carboxyl groups on the structural units of the acrylic acid-grafted rice husk (RH-g-AA). The sorption selectivity of the RH-g-AA for cations under competition with each other was high in the following order: Pb > Cu > Cd ≥ Fe > Mn > Zn > Ni > Mg > K > Cr > Ca. Sorption equilibrium of Pb on RH-g-AA was better described by the Fruendlich isotherm model than the Langmuir isotherm model. The sorption energy obtained from D-R model was 13.13 kJ/mol indicating an ion-exchange process as the primary sorption mechanism. Sorption kinetic data fitted with the pseudosecond- order kinetic model and indicated that both external and intraparticle diffusion took part in sorption processes. The RH-g-AA sorbent could be regenerated for more than 5 times by the washing process with 0.1 M HCl without a serious lowering the sorption capacity.
