Resumo

DE LA PENA-TORRES, A. et al. Arsenic adsorption and desorption on syntetic iron oxyhydroxides as study model to explain one of the mechanisms for its lixiviation from mining tailings. Rev. Mex. Ing. Quím [online]. 2012, vol.11, n.3, pp.495-503. ISSN 1665-2738.

This work presents a study of arsenic adsorption kinetics and equilibrium on synthetic iron oxyhydrates and its extraction by bicarbonate solutions, as a model to exp lain the fast way for arsenic lixaviation from mining tailings by this mechanism. The arsenic adsorption on synthetic goethite and ferrihydrite showed a pseudo-first order kinetics, reaching the equilibrium in 6-7 days. The adsorption isotherms for arsenic on synthetic goethite and ferrihydrite carried out at different temperaaures levels showed the same and maximum adsorption capacity of 15-18 mg/g, presented a best fil according lo Langmuir Isotherm Model; 95% of arsenic adsorbed in these materials was extracted with bicarbonate solutions 0.5 M, pH 8.5 in 2 h. Approximately 25% of total arsenic present in the mine tailings was extracted by bicaabonate solutions in 6 h. The results suggest that in these tailings, there is an arsenic fraction bound to iron oxyhydrates thaf can be quickly lixiviated by bicarbonate s olutions.

Palavras-chave : aisenic; mining tailinga; adsorption-desorption; iron oxyhydrates.