Influence of redox mediators and salinity level on the (bio)transformation of Direct Blue 71: kinetics aspects. (1st December 2016)

• Record Type: Journal Article
• Authors: Alvarez, Luis H.; Meza-Escalante, Edna R.; Gortáres-Moroyoqui, Pablo; Morales, Luz; Rosas, Krystal; García-Reyes, Bernardo; García-González, Alicone
• Is Part Of: Journal of environmental management. Volume 183:Part 1(2016)
• Page Start: 84
• Page End: 89
• Publication Date: 2016-12-01
• Subjects: Azo dyes -- Humic substances -- Redox mediators -- Marine consortium -- Salinity; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2016.08.044
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: The rate-limiting step of azo dye decolorization was elucidated by exploring the microbial reduction of a model quinone and the chemical decolorization by previously reduced quinone at different salinity conditions (2–8%). Microbial experiments were performed in batch with a marine consortium. The decolorization of Direct Blue 71 (DB71) by the marine consortium at 2% salinity, mediated with anthraquinone-2, 6-disulfonate (AQDS), showed the highest rate of decolorization as compared with those obtained with riboflavin, and two samples of humic acids. Moreover, the incubations at different salinity conditions (0–8%) performed with AQDS showed that the highest rate of decolorization of DB71 by the marine consortium occurred at 2% and 4% salinity. In addition, the highest microbial reduction rate of AQDS occurred in incubations at 0%, 2%, and 4% of salinity. The chemical reduction of DB71 by reduced AQDS occurred in two stages and proceeded faster at 4% and 6% salinity. The results indicate that the rate-limiting step during azo decolorization was the microbial reduction of AQDS. Graphical abstract: Highlights: A marine consortium uses humic substances as redox mediators for azo dye treatment. Azo dye reduction was evaluated at different salt conditions using redox mediators. The rate limiting step of azo dye reduction is the microbial reduction of AQDS.