Isotherms, kinetics and thermodynamics of industrial dye acid red 27 adsorption on Sugarcane Bagasse Ash

Joana Eliza de Santana; Fábio Gabriel Silva de Andrade; Aldebarã Fausto Ferreira; Marcos Gomes Ghislandi; Maurício Alves da Motta Sobrinho

doi:10.1007/s11356-024-31917-x

Isotherms, kinetics and thermodynamics of industrial dye acid red 27 adsorption on Sugarcane Bagasse Ash

Environ Sci Pollut Res Int. 2024 Jan 11. doi: 10.1007/s11356-024-31917-x. Online ahead of print.

Authors

Joana Eliza de Santana¹, Fábio Gabriel Silva de Andrade², Aldebarã Fausto Ferreira³, Marcos Gomes Ghislandi⁴, Maurício Alves da Motta Sobrinho²

Affiliations

¹ Chemical Engineering Department, Federal University of Pernambuco, Recife, PE, 50.740-590, Brazil. joana.santana@ufpe.br.
² Chemical Engineering Department, Federal University of Pernambuco, Recife, PE, 50.740-590, Brazil.
³ Departament of Fundamental Chemistry, Federal University of Pernambuco, Recife, PE, 50.740-590, Brazil.
⁴ Engineering Campus, Federal Rural University of Pernambuco, Cabo de Santo Agostinho, PE, 54518-430, Brazil.

PMID: 38206467
DOI: 10.1007/s11356-024-31917-x

Abstract

In this study, sugarcane bagasse ash (SCBA), obtained as residue from the sugar mill, was used as an adsorbent for Acid Red 27 (AR27) removal from aqueous solutions. The ash characterization data showed 23.63% of organic compounds and silica (α-SiO₂) as the most expressive inorganic compound (confirmed by X-ray diffractogram), the BET surface area had a value of 62.79 m².g^-1 and the pH_pzc was 8.45. Regarding the adsorptive tests, the optimal initial pH to the dye removal was 2.0. The adsorption equilibrium reached in about 4 h contact time and optimum SCBA dosage was found to be 4 g.L^-1. The pseudo-second order model best represented the adsorption kinetics. The Freundlich equation presented the best fit to the equilibrium data for the removal of AR27 by ash, with maximum adsorption capacity of 15 mg.g^-1 at pH 2.0. Thermodynamic study indicate that AR27 adsorption on SCBA occurs through a physisorption mechanism, with ΔHº_ads < 15 kJ.mol^-1. The ΔHº_ads evaluated by Vant' Hoff equation was explained as a combination of water desorption enthalpy, ΔHº_W and isosteric like enthalpy, ΔHº_D for the dye adsorption in liquid environment. The ΔHº_D = 9.2 kJ.mol^-1 was calculated from Clausius-Clapeyron approach. The effects of coexisting anions on the adsorption and regeneration and reuse of the adsorbent were also investigated. This study suggests that SCBA, which was used without any pretreatment, has the potential to be applied as a low-cost adsorbent to mitigate effluents contamination with AR27 dye at low concentrations.

Keywords: Adsorption kinetics; Decontamination; Dye adsorption; Isosteric enthalpy; Isotherms; Sugar mill waste; Sustainability.

Abstract

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