Adsorption of malachite green by activated carbon derived from gasified Hevea brasiliensis root

Abstract

One of the challenges in biomass gasification industry is the solid waste disposal mostly in the form of char. This article aims to prepare the gasified Hevea brasiliensis root based activated carbon (GHBRAC) for the sequestration of malachite green (MG) dye, to analyse the GHBRAC characteristics that are responsible for adsorption and to evaluate the MG uptake capacities of the prepared GHBRAC. The gasified Hevea brasiliensis root (GHBR) was obtained from commercial gasification plant and physiochemically treated with potassium hydroxide (impregnation ratios = 2.00) and carbon dioxide (flowrate = 150 cm3/min) via microwave irradiation (radiation power = 616 W). The total pore volume (TPV) and BET surface area (SBET) of GHBRAC were 0.273 cm3 and 477.74 m2/g respectively. The isothermal data best fitted to the n-BET model while the kinetic data followed the Avrami model equation, revealing a multilayer adsorption. The thermodynamic data of MG adsorption by GHBRAC showed that the process was spontaneous and endothermic. The Yoon–Nelson, Thomas and Yan models effectively predicted the adsorption of MG in fixed-bed column. GHBRAC was found to be economically feasible for commercialization owing to its low production cost and high adsorption capacity.

Keywords

• Gasification waste
• Adsorption kinetics
• Activated carbon
• Characterization
• Adsorption