Chromium tanned leather waste acid extraction, residue recycling and anaerobic biodegradation tests on extracts

• Type: Chapter or Part of a Book
• Date: 2011

Authors

Ferreira, M.J. (Author) Other; Almeida, M.F. (Author) FEUP; Pinto, V. (Author) Other; Santos, I. (Author) Other; Freitas, F. (Author) Other; Rodrigues J. L. (Author) Other; Pinho S. C. (Author) FEUP

Book

Title: Biodegradable Polymers and Sustainable Polymers (BIOPOL-2009)

Pages: 205-224

ISBN: 9781612095202

Indexing

Scopus - 0 Citations

Scientific classification

CORDIS: Technological sciences

FOS: Engineering and technology > Other engineering and technologies

Other information

Authenticus ID: P-008-YTC

Abstract (EN): Chromium sulfate tanned leather wastes are currently mainly landfilled, despite their content in valuable biopolymers and minerals. A more sustainable option might be recovering as much as possible of its chromium and, consequently, lowering its content in the resulting leather scrap, thus facilitating the recycling of the remaining material. With this objective, chromium leather scrap was leached with sulfuric acid solutions at low temperature (296 and 313 K) aiming at maximizing chromium removal with minimum attack to the leather matrix. Although reasonable Cr recoveries were achieved (30 and 60 %), chromium in eluate from leaching the residue according to DIN 38414-S4:1984 standard exceeded the threshold value, being considered hazardous. Thus, it was methodically washed with water and alkaline solutions in order to remove or stabilize the chromium de-linked from collagen. Furthermore, the so-treated leather scrap was recycled in rubber compounds for shoe soles application, confirming its potential to improve tear resistance. However, fine tune of the formulation is necessary to avoid failure due to poor tensile strength. The anaerobic biodegradation of the acid solution resulting from Cr recovery was evaluated indicating anaerobic biodegradability in the range of 25 to 45 %. © 2011 Nova Science Publishers, Inc.

Language: English

Type (Professor's evaluation): Scientific