Decolorizaton of methylene blue dye using magnetic ananas comosus leaf

Abstract

The study was conducted to investigate the feasibility of using magnetic Ananas comosus leaf (MACL) as adsorbent for the removal of Methylene Blue (MB) dye. Ananas comosus leaf (ACL) was chosen due the availability of this waste material.The ACL was first pretreated with different concentration of nitric acid, HNO3 to compare its surface area before modification process. Following that, ACL with the highest surface area was selected to produce MACL by precipitation of iron oxide on the surface of ACL. Both adsorbents, ACL and MACL were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), Scanning Electron microscopy (SEM) and Energy Dispersive X-Ray (EDX). The BET surface area of ACL and MACL recorded are 35.20 m2/g and 81.42 m2/g respectively. Equilibrium and kinetic studies were carried out under different pH of MB solution, adsorbent dosage, contact time and initial MB concentration. The equilibrium data were fitted to Langmuir and Freundlich isotherms. The equilibrium adsorption for both ACL and MACL were best described by the Langmuir isotherm, with MACL exhibiting a larger adsorption capacity compared to ACL. The sorption data was also analysed using pseudo-first-order and pseudo-second-order kinetic model. The experimental data obtained was found to follow pseudo-second-order with correlation coefficient R2 of 0.9889 and 0.9998 for ACL and MACL respectively.