New research from NZ

New biochar paper based on research from Massey University…

Stabilizing Chromium from Leather Waste in Biochar

“Disposal of chrome-tanned leather waste provides an environmental challenge, with land-based methods risking leaching of chromium into the environment. We investigate the production of biochar from leather as an alternative means to dispose of leather waste. Chrome-tanned leather is heated at 500–1000 °C in an environment excluding oxygen to form biochar. The char is leached in 1 M HCl for 15 h, and the leachate is analyzed for Cr to confirm that Cr does not leach from char formed at or above 600 °C. The char is analyzed by X-ray absorption spectroscopy (XAS) for chemical state and structure. X-ray absorption near edge structure (XANES) analysis shows that the leather and biochar contain Cr as a mixture of Cr sulfate and Cr carbide, with the proportion of Cr as carbide increasing from 0% for untreated leather to 88% for char formed at 1000 °C. Modeling of the extended X-ray absorption fine structure (EXAFS) spectra shows that the atomic near-range structure is consistent with that of chromium carbide for the high-temperature samples. Biochar produced from chrome-tanned leather waste contains highly dispersed chromium present as a stable, carbide-like structure (provided sufficiently high temperatures are used). This material, rather than being an environmental problem, may be used for soil remediation and carbon sequestration.”

Hannah C. Wells, Katie H. Sizeland, Richard L. Edmonds, William Aitkenhead, Peter Kappen§, Chris Glover§, Bernt Johannessen§, and Richard G. Haverkamp*
School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
Leather and Shoe Research Association, P.O. Box 8094, Palmerston North 4446, New Zealand
§ Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia

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