Adsorption of methylene blue using fish scales as biosorbent

Abstract

Access to water is fundamental for several sectors, such as human supply, irrigation, livestock, transport, energy, and manufacturing. However, the growing consumption associated with population increase, socio-economic and technological development, urbanization, and climate change, has substantially changed the availability and quality of this resource, mainly due to wastewater with dyes. Thus, the present study aims to evaluate the adsorption capacity of the tilapia fish scales (FS) as a biosorbent in removing the methylene blue dye (MB). The adsorption tests were carried out in batch mode, evaluating the effect of the MB concentration (10 - 40 mg L-1), through the study of equilibrium, considering the Langmuir and Freundlich adsorption isotherms and kinetic adsorption of pseudo-first-order (PFO) and pseudo-second-order (PSO), with the biosorbent concentration of 0.7 g L-1. It was observed that the more significant removal was achieved at 10 mg L-1 of MB (50.87%). Regarding the kinetic and equilibrium adsorption, all systems showed considerable adjustment to the PFO model and Freundlich isotherm model, respectively, coming into equilibrium after 15 minutes. Therefore, it is emphasized that the fish scale waste has great potential for application as a biosorbent to remove synthetic dyes, meeting the theme of sustainable development.