Preparation of activated carbon from leather waste: A new material containing small particle of chromium oxide

摘要

The tanning industry generates large amount of solid and liquid residues from the tannery process, which uses chromium (III) to obtain the wet blue leather. The solid residues (sawdust and scraps) contain around 3% in mass of chromium (III). The wet blue leather waste after controlled pyrolysis under CO_2 flow was transformed into chromium-containing activated carbons (AC). The AC showed high microporous surface area (up to 889m~2 g~(-1)). The fibrous structure of the starting material is kept after pyrolysis under CO_2 activation. Thermal analysis showed that the AC is stable up to 300℃, and the ash content of 6.9%. The chromium species were found to be Cr~(3+) and Cr~(6+) by XPS analysis. The chromium oxide was nanodispersed on the activated carbon, and the particle size increases with higher activation time.