Adsorption mechanisms of azo dyes binary mixture onto different raw palm wastes

This work aimed to understand the adsorption mechanism of dyes in a binary system onto different raw palm wastes and highlights its high efficiency for the removal of methylene blue and methyl orange in competition in aqueous solution. The proposition of the mechanism was based on several parameters and results for that several studies were performed. Characterisation of the specific surface by the methylene blue method and scanning electron microscopy was carried out to study the specific surface measurement and the surface morphology, respectively, on different raw palm wastes. The central composite design was used to evaluate the effects of the following factors (the solution pH and sorbent dose) also to optimise the experimental conditions. Based on CCD results the optimal conditions are pH = 7 and 90 mg for the adsorbent mass. The kinetic parameters calculated using different models show that the adsorption of the mixture of methyl orange (MO) and methylene blue (MB) is fitted to pseudo-first-order. Langmuir isotherm was found to be an adequate model describing the process in its several systems with an amount of adsorbed quantities of about 32.05 mg.g(-1) for MB and 16.81 mg.g(-1) for MO.