Finished leather waste chromium acid extraction and anaerobic biodegradation of the products

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Maria J. Ferreira (Author) Other; Manuel F. Almeida (Author) FEUP; Sílvia C. Pinho (Author) FEUP; Isabel C. Santos (Author) Other

Journal

Title: Waste Management

Vol. 30 No. 6

Pages: 1091-1100

ISSN: 0956-053X

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 12 Citations

ISI Web of Science

Scopus - 28 Citations

Scientific classification

FOS: Engineering and technology > Environmental engineering

CORDIS: Technological sciences > Engineering > Materials engineering

Other information

Authenticus ID: P-003-6MK

DOI: 10.1016/j.wasman.2009.12.006

Abstract (EN): Due to the amounts of chromium in the leachate resulting from leather leaching tests, chromium sulfate tanned leather wastes are very often considered hazardous wastes. To overcome this problem, one option could be recovering the chromium and, consequently, lowering its content in the leather scrap. With this objective, chromium leather scrap was leached with sulfuric acid solutions at low temperature also aiming at maximizing chromium removal with minimum attack of the leather matrix. The effects of leather scrap dimension, sulfuric acid and sodium sulfate concentration in the solutions, as well as extraction time and temperature on chromium recovery were studied, and, additionally, organic matrix degradation was evaluated. The best conditions found for chromium recovery were leather scrap conditioning using 25 mL of concentrated H(2)SO(4)/L solution at 293 or 313 K during 3 or 6 days. Under such conditions, 30-60 +/- 5% of chromium was recovered and as low as 3-6 +/- 1% of the leather total organic carbon (TOC) was dissolved. Using such treatment, the leather scrap area and volume are reduced and the residue is a more brittle material showing enhanced anaerobic biodegradability. Although good recovery results were achieved, due to the fact that the amount of chromium in eluate exceeded the threshold value this waste was still hazardous. Thus, it needs to be methodically washed in order to remove all the chromium de-linked from collagen.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10