Removal of trivalent chromium(III) from solution by biosorption in cork powder

The removal of trivalent chromium from solutions using biosorption in cork powder is described. The adsorption isotherm was determined, along with the effect of different variables, such as biomass particle size, solid-liquid ratio, reaction time, metal concentration and pH, on the efficiency of chromium removal. It was concluded that the adsorption is slow and favoured by an increase in pH. Therefore, using a solid-liquid ratio of 4 g dm(-3) it is possible to reduce the chromium concentration in the solution from 10 mg dm(-3) to less than 1.5 mg dm(-3) in 2h at 22degreesC. The kinetic studies verified that the sorption of chromium by cork was described by a second-order model. The elution results showed that 50% of the chromium bound to the cork was eluted using 0.5 mol dm(-3) H2SO4 and that cork maintains its binding capacity over four cycles of biosorption/elution. (C) 2002 Society of Chemical Industry.