Evaluation of the adsorption process using green coconut mesocarp for removal of methylene blue dye

ABSTRACT Agroindustrial wastes are alternative and low cost materials, since considerable amounts of these are discarded in the environment, with potential use as adsorbent materials in the removal of pollutants, for example. In this sense, this work was carried out with the objective of evaluating the use of green coconut fiber as adsorbent in the removal of methylene blue dye in aqueous medium. The methylene blue dye is widely used by the textile industry and is present in its effluents and can contaminate the environment. The green coconut fiber was treated with HCl, NaOH and hexane. The evaluated parameters were pH, agitation time, kinetic mechanism and adsorption equilibrium. The kinetic data were adjusted to the Pseudo first order, Pseudo second order, Intraparticle diffusion and Quimisation models, resulting as the most suitable for the Pseudo second order model. The adsorption isotherms were delineated to the Langmuir and Freundlich models, the latter being the best fit for the experimental data obtained. The maximum adsorptive capacity was verified by treatment with HCl (0.1 mol L-1) that provided a significant increase in the maximum adsorptive capacity (166.67 mg g-1) of green coconut fiber compared to coconut fiber in and other treatments. The results showed that green coconut fiber, treated with hydrochloric acid, can be used as adsorbent material in the remediation of organic pollutants such as cationic dyes in liquid effluents.