Representative azo dyes (Acid Blue 113 [AB113] and Direct Black 38 [DB38]) were treated in a single step with soybean peroxidase (SBP) and hydrogen peroxide (H2O2), or in two steps, zero-valent iron (Fe°) pretreatment followed SBP/H2O2. The purpose of this research was to compare both treatment processes and to determine which one was the optimal for degradation of each azo dye. For AB113, the preferred process was the single-step process, 1.0 mM AB113 required 2.5 mM H2O2, 1.5 U/mL SBP at pH 4.0 for ≥ 95% color and dye removal and 30% total organic carbon (TOC) removal. For DB38, due to the products formed after Fe° reduction, which are enzyme substrates (aniline and benzidine; two of four products) a two-step process was preferred, which allowed reduction in the required SBP and H2O2 concentrations by 5- and 2-fold, respectively, compared to a single-step treatment for ≥ 95% color, dye, and aniline/benzidine removal and 88% TOC removal.
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http://dx.doi.org/10.2175/106143017X15131012153149 | DOI Listing |
Chemistry
December 2024
University of Pardubice: Univerzita Pardubice, Institute of Organic Chemistry and Technology, CZECHIA.
Differently substituted pyrrole-azo‑benzene molecular photoswitches were prepared in a straightforward synthetic way. Their fundamental properties were investigated by XRD analysis, differential scanning calorimetry, thermogravimetric analysis, cyclic voltammetry, UV‑Vis absorption spectroscopy, Hyper-Rayleigh Scattering, and NMR spectroscopy; the experimental results were further corroborated by DFT calculations. Thermal robustness, the HOMO/LUMO levels, and the absorption properties were altered mostly by substituting the N‑methylpyrrole moiety and further fine-tuned by modifying the benzene substituents.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa (ITQB NOVA), 2780-157, Oeiras, Portugal.
Electro-bioremediation of exemplary water pollutants such as nitrogenous, phosphorous, and sulphurous compounds, hydrocarbons, metals and azo dyes has already been studied at a macro-scale level using mixed cultures. The technology has been generally established as a proof of concept at the technology readiness level (TRL) of 3, and there are already specific cases where the technology reached TRL 5. However, this technology is less utilized compared to traditional approaches.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Environmental Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu, 600036, India. Electronic address:
The release of toxic chemical dyes from the industrial effluent poses huge challenges for the environmental engineers to treat it. Azo dyes encompass the huge part of textile discharges which are difficult to degrade due to their complex chemical aromatic structures and due to the presence of strong bonds (-N=N-). Thus, the removal of a carcinogenic azo dye (i.
View Article and Find Full Text PDFHeliyon
December 2024
Chemistry Department, Faculty of Science, Cairo University, Giza, 12613, Egypt.
The extensive use of azo dyes in textile and pharmaceutical industries pose significant environmental and health risks. This problem requires to be tackled forthwith through a cheap, environmentally friendly and viable approach to mitigate water pollution. In this context, the green synthesis method was used for synthesis of ZnO NPs.
View Article and Find Full Text PDFExtremophiles
December 2024
Miami College, Henan University, Kaifeng, 475000, Henan, China.
Azo dye wastewater has garnered significant attention from researchers because of its association with high-temperature, high-salt, and high-alkali conditions. In this study, consortium ZZ efficiently decolorized brown D3G under halophilic and thermophilic conditions. he results indicated that consortium ZZ, which was mainly dominated by Marinobacter, Bacillus, and Halomonas, was achieved decolorization rates ranging from 1 to 10% at temperatures between 40 °C and 50 °C, while maintaining a pH range of 7 to 10 for direct brown D3G degradation.
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