THE EQUILIBRIUM STUDY AND KINETICS OF ADSORPTION OF ZN (II) IONS ON COOKED TEA WASTE

Abstract

The sorbent potential of cooked tea waste (TW) for the Zn (II) heavy metal removal from aqueous solution was examined in a batch adsorption study. The various parameters investigated were the contact time, dose of sorbent, initial concentration of Zn (II) solution. It was revealed from the batch studies experiments that the equilibrium of the adsorption was achieved within 1.5 h. The hydroxyl and carboxyl functional groups were found mainly responsible from the Fourier transform infrared spectroscopy (FTIR) analysis for the adsorption of Zn (II) ions. The Langmuir and Freundlich models were used for the fit of equilibrium data. It was observed that data was best fit in the Langmuir model. The 10.75 mg/g at pH 5 was the adsorption capacity found. For the sorption rate study two kinetic models, pseudo-first-order, pseudo-second-order were applied. The correlation coefficient of 0.998 was obtained for pseudo-second-order model. From the results the sorbent potential of cooked tea waste (TW) was explored and was found good for removal of Zn (II) metal.