Removal of Malachite Green aqueous solution by Pomelo peel

Abstract

In this study, the adsorption capacity of pomelo peel powder for removal of malachite green (MG) dye in aqueous solution was investigated. Pomelo peel powder was analysed by Fourier transform infrared (FT-IR) spectroscopy and observed by scanning electron microscopy (SEM). SEM determined that the surface of pomelo peel powder become smoothly after adsorption. FT-IR indicate the presence of hydroxyl and methyl groups in the dried pomelo peel waste. Research were carried out by analysing the effect of contact time (20 min-180 min), the effect of initial MG concentration (20 mg/L-100 mg/L) and the effect of adsorbent dosage (0.1 g-0.5 g) on the efficiency of MG removal. The result showed that increase in contact time and initial concentration resulted in the increased of adsorption capacity. Besides, the percentage removal was increased as the adsorbent dosage increased. The maximum adsorption capacity and removal percentage obtained was 15.34 mg/g and 54.69% respectively at 30 ℃. Adsorption isotherm were modelled with Langmuir isotherm and Freundlich isotherm. The date fitted well with the Langmuir isotherm with R2=0.99. The kinetic data were investigated using pseudo-first order and pseudo-second order models. Pseudo-second order model was found to be fitted the process well with R2>0.997. The results showed that pomelo peel powder can be utilised as a low-cost adsorbent in decolourization of MG dye from aqueous solution.