Evaluation of biosorbents as an alternative for mercury cyanide removal from aqueous solution

[Display omitted] •Banana peel showed favorable adsorption isotherm for Hg(CN)2.•Drying of banana peel lower than 150 °C did not affect adsorption efficiency.•Adsorption of 94 % of Hg(CN)2 was achieved within 90 min by banana peel.•Banana peel was more selective for Hg(CN)2 than Au(CN)2.•Excess of C...

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Bibliographic Details
Published in:Minerals engineering 2023-12, Vol.204, p.108431, Article 108431
Main Authors: Aliprandini, Paula, Botelho, Amilton Barbosa, Veiga, Marcello M., Marshall, Bruce G., Scarazzato, Tatiana, Espinosa, Denise Crocce Romano
Format: Article
Language:English
Subjects:
Artisanal mining
ASGM
Biosorption
Gold
Hg removal
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Summary:[Display omitted] •Banana peel showed favorable adsorption isotherm for Hg(CN)2.•Drying of banana peel lower than 150 °C did not affect adsorption efficiency.•Adsorption of 94 % of Hg(CN)2 was achieved within 90 min by banana peel.•Banana peel was more selective for Hg(CN)2 than Au(CN)2.•Excess of CN– declined the adsorption of Au(CN)2. Worldwide, artisanal gold miners currently use and lose over 2000 t/year of mercury, which causes massive social and environmental problems. The combined use of mercury and cyanide by artisanal processing centers have exacerbated the bioavailability of the pollutant. Biosorbents have the capability to adsorb mercuric species in solution, and due their low cost and extensive availability close to mines, they can be used to detoxify effluents. In this study, four biosorbents were evaluated for mercury cyanide removal from simulated gold mining effluents: banana peel, passion fruit peel, eggshells, and chicken feathers. For each treatment, the adsorption capacity, equilibrium isotherms, and kinetic modeling were studied. Only banana peel showed favorable adsorption of Hg(CN)2, with a 94 % removal percentage within 90 min. The pseudo-first order model resulted in the same adsorption capacity as the experimental data (0.47 mg/g). The Sips isotherm model fitted the experimental data, indicating that the adsorption was monolayer-based. Banana peel was found to be more selective for mercury than for gold cyanide. Conversely, the excess of free cyanide had a negative effect on the adsorption efficiency.
ISSN:0892-6875
1872-9444
DOI:10.1016/j.mineng.2023.108431