Abstract

BROCHE-GALINDO, Maria Hertha; RODRIGUEZ-RICO, Iván Leandro; VILLAR, Maira Maria Pérez-  and  PRIETO-GARCIA, Julio Omar. Equilibrium and kinetic models in the adsorption of methylene blue on agro-industrial wastes. RTQ [online]. 2022, vol.42, n.3, pp. 420-434.  Epub Oct 15, 2022. ISSN 2224-6185.

Adsorption is one of the processes that can be used in industries to reduce the presence of pollutants in their effluents; the substitution of activated carbon by agro-industrial solid wastes has been explored, showing high efficiency in the removal of these compounds. To scale up this process, kinetic and equilibrium models are required for each adsorbate-adsorbent pair. In this work, equilibrium and kinetics were evaluated for sorghum-methylene blue and sugarcane bagasse-methylene blue agricultural residues in batch system with biomass concentration of 10 g/L, agitation of 80 rpm, pH of 5,5 u and particle size (0,35 - 0,63) mm at three different temperatures. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models were selected for isotherm representation and the pseudo first order, pseudo second order, Elovich and intraparticle diffusion models for process kinetics. The Temkin model presented the best fit to the isotherms, while the adsorption kinetics was best described by the Pseudo second order model, considering the criteria of correlation coefficient and statistical errors: sum of squares of the error and average relative error. These results indicate that adsorption is favorable and occurs by chemisorption.

Keywords : adsorption isotherms; kinetics; methylene blue; batch system.

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