Abstract

Tannery sludge used in agriculture contains much organic matter like a high-quality organic fertilizer. However, the excess chrome in tannery sludge limits its expanding use in agriculture. The absorption of chrome in different forms was studied in soil at different chrome concentrations and pHs. The research indicated that both Cr(III) and Cr(VI) were easily fixed by adsorption when they entered the soil. Adsorption of Cr(III) corresponded to Freundlich adsorption isothermal pattern, while that of Cr(VI) accorded with a Langmuir adsorption isothermal pattern. pH was the vital factor which effected the adsorption of Cr(III) and Cr(VI). Most of the chrome in tannery sludge would settle in the soil when it was used as a fertilizer in agriculture, because the chrome is mainly Cr(III).