Optimization of biosorption potential of nano biomass derived from walnut shell for the removal of Malachite Green from liquids solution: Experimental design approaches

Activated carbon based on walnut shell as a biomass material was synthesized and successfully applied for the removal of malachite green (MG) from aqueous solution. Fourier transform infrared spectroscopy, Transmission electron microscopy, Brunauer-Emmett-Teller, Dynamic light scattering and X-ray diffraction were used to characterize the biomass. In batch study, response surface methodology was utilized to screen and optimize key operating parameters with considering removal efficiency as a response. Central composite design was applied to indicate the influence of operating variables including initial concentration of MG (16.5-33.5 mgL(-1)), nano biomass dose (16.5-33A mg) and contact time (13.0-47.0 min) on MG uptake from the aqueous solution. Obtained results showed that about 100% elimination was attained at initial MG concentration of 33.3 mgL(-1), nano biomass dose of 33.3 mg and contact time of 20.0 min. Data analysis was done by different adsorption isotherms such as Langmuir, Temkin, Freundlich and Dubinin-Kaganer-Radushkevich (DKR) and the results introduced Langmuir isotherm as a suitable model to define the adsorption behaviors. Finally, the pseudo second order kinetic model described the MG sorption process with a well-fitting (R-2 = 0.9897). (C) 2019 Elsevier B.V. All rights reserved.