Bixin as a new class of biosorbent for Hg2+ removal from aqueous solutions.

Abstract
In this study, the apocarotenoid bixin was investigated as a potential biosorbent for Hg2+ in aqueous solutions. Bixin was used to form a thin film on an inert support using the drop-coating technique. This film was char- acterised using ATR-FTIR, SEM, and TGA-DTG techniques. Parameters that influence adsorption, such as pH, temperature, NaCl concentration, salt type, bixin mass, and supports for the bixin film, were evaluated. Using 0.112 mg of a bixin covering on a cellulose filter, the sorbent material was able to remove 75 % of Hg2+ from a 2.0 mL, 0.3 mg g− 1 , pH 6.00, 25 ◦C solution after 180 min of contact. Kinetics studies were carried out between 5 and 1440 min, and the pseudo-first-order adsorption model was applied. Equilibrium isotherm data were ana- lysed, and the best fit was for the non-linear Freundlich model, with an R2 of 0.9868, RMSE of 0.37, and maximum sorption capacity of 85.38 mg g− 1 obtained by the Langmuir model. The bixin film was applied in spiked environmental samples (lake and mining effluent), and it achieved 86 % Hg2+ removal. The results show that the bixin film is a suitable alternative for efficiently removing mercury from various aqueous systems. This introduces a new class of biosorbent based on apocarotenoids, which are sustainable, low cost, nontoxic, and easily obtainable.
Description
Keywords
Adsorption, Apocarotenoids, Biosorption, Heavy metals, Mercury
Citation
VIEIRA, J. C. et al. Bixin as a new class of biosorbent for Hg2+ removal from aqueous solutions. Environmental Nanotechnology, Monitoring & Management, v. 15, artigo 100407, 2021. Disponível em: <https://www.sciencedirect.com/science/article/pii/S2215153220303901?via%3Dihub>. Acesso em: 11 out. 2022.