ADSORPTION KINETICS OF Cd2+ IONS ONTO MgPz THIN FILM

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 Cd 2+ 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 2+ in aqueous solution. The lowest detection limit can reach 10 m g/ml Cd 2+ 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 pseudo-second-order  rate equation generates a straight line that best fit to the data of adsorption of Cd 2+ on Pz film.