KINETICS ASPECTS OF CHROMIUM (III) REMOVAL BY PRECIPITATE FLOTATION / ASPECTOS CINÉTICOS DA REMOÇÃO DE CROMO (III) POR FLOTAÇÃO DE PRECIPITADOS

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Heavy metals contained in industrial effluents are sources of great potential environmental degradation, since their presence produce physicochemical alterations harming in the quality of the water. These alterations have a direct impact in the mortality of the flora and fauna affecting indirectly the human health. This dissertation refers to the study of the kinetic aspects of chromium (III)removal by precipitate flotation from chromium chloride (CrCl3.6H2O), using sodium dodecylsulfate (SDS) as anionic collector. For this study, measurements of zeta potential were accomplished as well as chromium (III) tests of flotation to determine the appropriate parameters operation: gas flow rate, concentration of collector and frother. Measurements of zeta potential of the particles of chromium (III) hydroxide in the presence of indifferent electrolyte KCl, indicated an isoelectric point (PIE)in pH around 8,5. The particles of chromium (III) hydroxide in the presence of anionic collector (SDS) showed a decrease in module of the zeta potential, for the three levels of concentrations investigated, as well as a displacement of the PIE in the direction of the more inferior pH values. This behavior can be attributed to the adsorption of the anionic collector on Cr(OH)3 due to the electrostatic attraction. Chromium (III) removals of 96,2% were obtained by precipitate flotation. Residual values of chromium reached are lower than the standards values established by the CONAMA (20/86), that mean [Cr3+]£0,5 mg/L. The kinetic flotation study showed that the removal of chromium (III)hydroxide precipitates followed a first order model.

ASSUNTO(S)

flotacao de precipitados precipitate flotation cromo (iii) chromium (iii) liquids effluents cinetica de flotacao efluentes liquidos kinetics flotation

ACESSO AO ARTIGO

Documentos Relacionados