Adsorption of cadmium and chromium from wastewater by peat

Abstract
The removal of cadmium and chromium by adsorption on peat was investigated to determine the effects of contact time, pH and temperature. Results of batch studies showed that peat was effective in adsorbing a maximum of 95% of cadmium at 5°C and a maximum of 53% chromium in the wastewater at 21°C in the pH range 4 to 5 in an equilibrium time of 2 h. The adsorption of cadmium on peat was exothermic, while the adsorption of chromium on peat was endothermic. Isotherm analysis of adsorption data obtained at 5°C, 10°C, 15°C and 21°C showed that the adsorption pattern for cadmium and chromium on peat followed the Langmuir isotherm and Freudlich isotherm respectively at most of the temperatures.