RESUMO
Textile industry wastewater has become a cause of concern to environmentalists due to its toxic composition and the difficulty of breaking down certain dyes. In this study, modified fish scales of Sardinella brasiliensis (SSb) were used as an alternative for a low-cost adsorbent to remove dyes from textile wastewaters. Adsorption efficiency was assessed by measuring the general, kinetic, and thermodynamic physico-chemical parameters of adsorption isotherms, using Reactive Turquoise Blue 15 (RTB15) and Reactive Red 120 (RR120) dyes as adsorbate models, as local textile industries commonly use these dyes. The isothermal data from the batch experiments were inserted in the Langmuir, Freundlich, and Langmuir-Freundlich (SIPS) equations; the Langmuir isotherm equation showed the most appropriate. The thermodynamic parameters showed that adsorption of dyes by the modified SSb adsorbent was an endothermic yet spontaneous process in the case of RR120. Sorbent-based on SSb material was concluded as adsorbing both of the tested dyes. Because of its abundant availability, and the small amount of activation needed to turn it into an adsorbent, this biowaste can be employed as a low-cost alternative for removal of dyes in the treatment of textile wastewater.
