Revalorization of chromium-tanned leather shavings into carbon materials and re-tanning solution

Tanned leather is a product of high intrinsic value and a sign of luxury. Chromium-tanned leather shavings are abundantly produced wastes which contain chromium that could be revalorized. The present research proposes the use of alkaline hydrolysis, aided by an inorganic anion, to promote the hydrolysis of the Cr–O bond. De-chromed solids were employed to synthesize carbon material, which subsequently was applied for dye removal from aqueous solution, while the chromium-rich solution was used as a re-tanning agent. The results demonstrated that it is possible to develop a method of chromium-protein separation, with a minimum degree of hydrolyzation. When an activating agent was employed, the prepared carbon had a surface area of 585 m 2 /g, with trace levels of chromium (