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Biogenic sulfide for azo dye decolorization from textile dyeing wastewater
Qian Zeng1, Yu Wang2, Feixiang Zan1
1Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Chemosphere
|June 16, 2021
Summary
Biogenic sulfide, produced by sulfate-reducing bacteria (SRB), directly breaks azo bonds in dyes, leading to effective decolorization. This process significantly enhances azo dye removal efficiency in wastewater treatment.
Area of Science:
- Environmental Microbiology
- Industrial Biotechnology
- Water Treatment
Background:
- Azo dyes are widely used in the textile industry.
- The sulfidogenic process is effective for azo dye removal, but the role of biogenic sulfide is not fully understood.
Purpose of the Study:
- To investigate the mechanism of biogenic sulfide in decolorizing the model azo dye Direct Red 81 (DR 81).
- To explore factors influencing the decolorization rate.
Main Methods:
- Biotic and abiotic batch tests were conducted.
- Analysis of azo dye degradation intermediates was performed.
Main Results:
- Biogenic sulfide directly cleaved azo bonds (-NN-), causing decolorization.
- Decolorization rates increased nearly 3-fold with external carbon sources or higher dye concentrations, achieving >99% removal.
- Degradation intermediates were identified.
Conclusions:
- Biogenic sulfide plays a crucial role in azo dye decolorization.
- This finding offers a new application for sulfidogenic systems in treating azo dye wastewater.
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