Cinética de la absorción de cromo(III) por algas Nostoc sp.

Abstract

An alga arising from Lake Titicaca basin (Bolivia, South America), has been studied faced with adsorption kinetics of Cr(III). The samples of Nostoc sp. were put in contact with chromium (III) solutions at 18°C. The pH effect has been measured from 2.50 up to 5.40. Concentration-time profiles shown exponential functions or first order processes. There is a linear relationship between pH and rate constants k o from 8.0x10-3 min-1 to 8.3x10-2 min-¹. At low pH, metal adsorption is negligible and maximum at high pH. Different initial concentrations of Cr(III), yielded also first order rate constants between 2.9x10-²min-¹ and 5.0x10-3min-1. Hydrogen ions would be competing against metal ions in order to achieve active sites. As possible mechanisms, not only the ion exchange could be involved, but also complex

An alga arising from Lake Titicaca basin (Bolivia, South America), has been studied faced with adsorption kinetics of Cr(III). The samples of Nostoc sp. were put in contact with chromium (III) solutions at 18°C. The pH effect has been measured from 2.50 up to 5.40. Concentration-time profiles shown exponential functions or first order processes. There is a linear relationship between pH and rate constants k o from 8.0x10-3 min-1 to 8.3x10-2 min-¹. At low pH, metal adsorption is negligible and maximum at high pH. Different initial concentrations of Cr(III), yielded also first order rate constants between 2.9x10-²min-¹ and 5.0x10-3min-1. Hydrogen ions would be competing against metal ions in order to achieve active sites. As possible mechanisms, not only the ion exchange could be involved, but also complex