Three beta-cyclodextrin (polymers 1-3) and a starch-based (polymer 4) polymers were synthesized using hexamethylene diisocyanate (HMDI) as a cross-linking agent in dry dimethylformamide and used as a sorbent for the removal of some selected azo dyes from aqueous solutions. The cross-linked polymers were characterized by Fourier transform infrared spectroscopy, thermogravimetric and differential scanning calorimetric analysis. Results of sorption showed that cyclodextrin and starch based polymers can be effectively used as a sorbent for the removal of anionic azo dyes. The Influence of the amide groups and the chemical structure of azo dyes are also studied. Results of sorption experiments showed that these adsorbent exhibited high sorption capacities toward Direct Violent 51 (80% for polymer 1, 69% for polymer 2, 70% for polymer 3 and 78% for polymer 4). The sorption capacity of dyes on the polymers was dependent on the presence of sulfonate groups of the anionic dyes. In order to explain the results an adsorption mechanism mainly physical adsorption and interactions such as hydrogen bonding, ion-exchange due to the nature of the polymer network and the formation of an inclusion complex due to the beta-CD molecules through host-guest interaction is proposed.
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http://dx.doi.org/10.1016/j.biortech.2007.01.023 | 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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