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Zero‐Valent Iron Pretreatment for Enhancing the Biodegradability of Azo Dyes
Author(s) -
Perey Jennie R.,
Chiu Pei C.,
Huang ChinPao,
Cha Daniel K.
Publication year - 2002
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143002x139938
Subject(s) - biodegradation , zerovalent iron , chemistry , zero (linguistics) , environmental chemistry , nuclear chemistry , organic chemistry , adsorption , philosophy , linguistics
Azo dyes are a group of chemicals that are largely resistant to aerobic biodegradation and persist in wastewater treatment processes. This study proposed that zero‐valent iron can be used to reduce the azo bond, cleaving the dye molecule into products that are more amenable to mineralization by bacteria in biological treatment processes such as activated sludge. Batch anaerobic reduction experiments were performed using two azo dyes, orange G and orange II, to determine reaction kinetics and to identify reduction products. Iron‐treated dye solutions were subjected to batch biodegradation tests and respirometric analyses to screen for enhanced biodegradability over parent dyes. Results indicate that treatment of orange G and orange II with scrap iron produces aniline and sulfanilic acid as significant products that are degraded by an acclimated culture within 24 hours. Respirometric data illustrated that iron‐treated dye solutions exert a significantly higher biochemical oxygen demand than the solutions containing orange G and orange II, demonstrating that recalcitrant azo dyes can be aerobically biodegraded after iron pretreatment.