Preparation of High Exhaust Chrome from Leather Shavings and Hydrocarbons with its Application in Leather Processing for Green Tanning Technology

Abstract

The use of chrome in tanning has made the remarkable advances to achieve the best quality and quantity of leather. But the chrome tanning process is associated with the generation of heavy metal containing solid wastes and toxic effluents. To solve the environmental issues we emphasized on the development of high exhaust chrome complex from chrome containing leather wastes that could minimize the toxic effluents up to negligible limit. Therefore in the synthetic process of chrome tanning material, the chrome shavings and the hydrocarbons have been utilized as a reductant as well as the potential masking intermediates. These chrome tanning materials have been prepared using leather shavings alone in product A, partial replacement of shavings by hydrocarbons for product B and then replacement of hydrocarbons by molasses for product C. The materials have been employed for the tanning of goat skins parallel to the commercial basic chromium sulfate (BCS).The comparative tanning studies revealed that, the quality of leather made from product B is either better or comparable with those of product A, C and the conventional tanning material. Shrinkage temperature of this leather was more than 120 C after an offer of 1.65 % Cr₂O₃. The amount of Cr₂O₃, in the leather resulted from product B has been found more than others with the simultaneous elevation in spent chrome liquor. Hence the exhaustion rate of product B has been noted up to 95%. While the physical characterstics of resulted leather from product A, B, and C have been found comparable to that of conventional tanned leather. Therefore, this methodology would not only reduce toxic effluents and chrome containing solid wastes but also provide quality leather and higher economic return.