ADSORPTION KINETICS OF Cd2+ IONS ONTO MgPz THIN FILM

Abstract

A (2,3,7,8,12,13,17,18-Octakis(4-tert-butylbenzylthio)-porphyrazinato)Mg(II) functionalized quartz crystal microbalance sensor has been developed for the detection of trace Cd2+ions in water samples. The quartz crystal microbalance results indicated that the MgPz coated sensor exhibited high sensitivity, stability and selectivity for the detection of Cd in aqueous solution. The lowest detection limit can reach 10 ?g/ml Cd2+ in aqueous solution, which resulted in the frequency shift of ? 150 Hz. The observed adsorption data were analyzed using four adsorption kinetic models; the Elovich equation, Ritchie's equation, pseudo first- and second-order equations. Results show that the linear regression analysis with respect to pseudosecond-order rate equation generates a straight line that best fit to the data of adsorption of Cd2+ on Pz film.