ADSORPTION OF MALACHITE GREEN INTO POTATO PEEL: NONLINEAR ISOTHERM AND KINETIC

Abstract

Potato peels (PPs) were utilized for removal of malachite green (MG) from aqueous solutions. The adsorbent underwent characterization through attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR), Scanning electron microscope (SEM), point zero charge (pHPZC) X-Ray diffraction (XRD), and Energy dispersive X-ray spectroscopy (EDX). The removal of MG was found to be significantly influenced by pH, temperature, contact time, and initial concentration. Temperature and particle size were determined to have lesser influence compared to other factors. The adsorption process lasted for 120 minutes, with rapid removal occurring within the first 60 minutes. Adsorption kinetics were analyzed using the Elovich, pseudo first order, and pseudo second order models. The pseudo second order model was found to be more suitable for the kinetic study. Isotherm modeling was conducted using the Temkin, Freundlich, and Langmuir isotherms. Due to the exothermic nature of the study, the Freundlich and Langmuir models were found to be highly compatible. The maximum adsorption capacity was determined as 37.8 mg/g at 41°C. ATR-FTIR analysis revealed the involvement of hydroxide and carbonyl groups in the adsorption process. Overall, this study concluded that PPs is promising adsorbent for removal of MG from aqueous solutions.