Degradation Of Azo Dye Research Articles

Light-gated specific oxidase-like activity of a self-assembled Pt(II) nanozyme for environmental remediation.

Artificial enzyme equivalents, also known as nanozymes, are a practical tool for environmental remediation when compared to their natural counterparts due to their high operational stability, efficiency, and cost-effectiveness. Specific oxidase mimicking nanozymes are well suited to degrade toxic chemicals from industrial waste such as phenols and azo dyes. Therefore, photocatalytic nanozymes using visible/sunlight would provide a viable strategy for sustainable environmental remediation. Herein, we introduce an aggregation-induced emissive Pt(II) complex, which self-assembles in water providing NanoPtA nanotapes. These structures exhibit a specific oxidase-like nanozyme activity driven by light. The NanoPtA structure assists in the photogeneration of singlet oxygen in water via a triplet excited 3MMLCT state, leading to a specific oxidase-like activity instead of a peroxidase-like activity. The self-assembled nanozyme showed great stability under harsh environmental conditions and exhibited photo-induced specific oxidase-mimetic activity, which was considerably more efficient than the natural enzyme or other specific nanozymes. We demonstrated efficient NanoPtA-induced photocatalytic degradation of various phenolic compounds and azo dyes within 5-10 minutes of light irradiation. Notably, the system operates under sunlight and exhibits reusability over twenty cycles of catalytic reactions. Another fascinating aspect of NanoPtA is the unaltered catalytic performance for more than 75 days, providing a robust enzyme-equivalent for practical sustainable environmental remediation.

Catalytic degradation of azo dyes by bimetallic nanoparticles loaded in smart polymer microgels.

The contamination of water by azo dyes is increasing rapidly due to their waste use in textile industries. These dyes are very toxic for living things. Therefore, it is very important to remove these dyes from water. Various materials are reported for this purpose. Here, the most effective system of bimetallic nanoparticles in smart polymer microgels was prepared. The microgel system of N-isopropylmethacrylamide (NMA) (monomer) and methacrylic acid (MAa) (comonomer) was synthesized by a free radical precipitation polymerization method and then bimetallic (Ag/Ni) nanoparticles were encapsulated into the P(NMA-MAa) microgels by in situ reduction of both silver and nickel salts by NaBH4 (reductant) after insertion of both (Ag+/Ni2+) ions. The P(NMA-MAa) microgels and Ag/Ni-P(NMA-MAa) hybrid microgels were characterized with FTIR, UV-vis, TGA, XRD, DLS, EDX, and STEM. The pH and temperature responsive behavior of Ag/Ni-P(NMA-MAa) was also evaluated. The catalytic efficiency of Ag/Ni-P(NMA-MAa) was assessed for degradation of methyl orange (MOr), congo red (CRe), eriochrome black T (EBlT) and methyl red (MRe) dyes under various conditions in aqueous medium. The apparent rate constant (k 0) value for MOr, CRe, EBlT and MRe was found to be 0.925 min-1, 0.486 min-1, 0.540 min-1 and 0.525 min-1 respectively. The Ag/Ni-P(NMA-MAa) was found to be an excellent recyclable catalyst.

Enhanced Anaerobic Degradation of Azo Dyes by Biofilms Supported by Novel Functionalized Carriers

Enhanced Anaerobic Degradation of Azo Dyes by Biofilms Supported by Novel Functionalized Carriers

Polymer microgel-based gold nanocomposites for reductive degradation of azo dyes

Polymer microgel-based gold nanocomposites for reductive degradation of azo dyes

"Azo Dyes Degradation Approaches and Challenges: An Overview"

"Azo Dyes Degradation Approaches and Challenges: An Overview"

"Azo Dyes Degradation Approaches and Challenges: An Overview"

"Azo Dyes Degradation Approaches and Challenges: An Overview"

Bacterial oxidoreductive enzymes as molecular weapons for the degradation and metabolism of the toxic azo dyes in wastewater: a review

Abstract Azo dyes are extremely toxic and pose significant environmental and health risks. Consequently, mineralization and conversion to simple compounds are required to avoid their hazardous effects. A variety of enzymes from the bacterial system are thought to be involved in the degradation and metabolism of azo dyes. Bioremediation, a cost effective and eco-friendly biotechnology, involving bacteria is powered by bacterial enzymes. As mentioned, several enzymes from the bacterial system serve as molecular weapons in the degradation of these dyes. Among these enzymes, azoreductase, oxidoreductase, and laccase are of great interest for the degradation and decolorization of azo dyes. Combination of the oxidative and reductive enzymes is used for the removal of azo dyes from water. The aim of this review article is to provide information on the importance of bacterial enzymes. The review also discusses the genetically modified microorganisms in the biodegradation of azo dyes in polluted water.

Continuous Flow Photooxidative Degradation of Azo Dyes with Biomass‐Derived Carbon Dots

AbstractThe presence of persistent organic pollutants in industrial wastewaters is becoming a problem of major concern. In the present study we explored the degradation of azo dyes, well‐known common hazardous contaminants, by a green and efficient procedure using continuous flow photooxidative degradation. In particular, carbon dots synthesized from fishery waste (bass‐CDs) were used as a cheap and readily available photocatalyst in combination with oxygen and UV light. Methyl orange, acid red 18, amaranth, sunset yellow and chromotrope were chosen as model substrates and their degradation was studied both in batch and in continuous flow conditions. All the azo dyes were fully degraded with both techniques highlighting the suitability of bass‐CDs for the decontamination of wastewater. The main advantages are of using a “disposable” photocatalyst, in aqueous solvent and in continuous flow. In particular, continuous flow operation allowed faster decompositions: circa 2 min versus 1–3 hours needed in batch.

Enhanced decolourisation and degradation of azo dyes using wild versus mutagenic improved bacterial strain: a review

Enhanced decolourisation and degradation of azo dyes using wild versus mutagenic improved bacterial strain: a review

Fluorinated covalent organic framework materials for photocatalytically driven benzylamine coupling and azo dyes degradation

Covalent organic frameworks (COFs) with pre-designed structures and superior photophysical properties have attracted significant attention due to their applications in photocatalysis. In this research, an imine-linked fluorinated 2D-COF (TFA-TTA-COF) material was feasibly fabricated from polycondensation of 2,3,5,6-tetrafluoroterephthalaldehyde (TFA) and 4,4′,4′'-(1,3,5-triazine-2,4,6-triyl)trianiline (TTA) in solvent-thermal methods. The TFA-TTA-COF material exhibited excellent crystallinity, high Brunauer-Emmett-Teller surface area of 1504 m2·g−1, and superior thermal and chemical stability. Considering the advantages of enhanced light absorption, effective charge separation and charge transfer, the prepared TFA-TTA-COF was employed as photocatalyst for the degradation of dyes. The degradation efficiencies of Eriochrome Black T (EBT) and Eriochrome Black A (EBA) dye in water could attain 89 % and 82 %, respectively. Furthermore, TFA-TTA-COF was found to show satisfactory photocatalytic performance with high conversion and selectivity in the photo-driven oxidative coupling of benzylamines. This work demonstrated the important contributions to the development of heterogeneous COFs-based photocatalysts.

Azo Dyes Degradation Approaches and Challenges: An Overview

Dyes play a very important role in our daily lives. The dye industries started manufacturingdyes with natural sources and then turned towards synthetic ones. Among these dyes, about60% of the total dyes are azo dyes which are used in industries. They are mostly used as textiledyes because they are easy to synthesize, chemically stable and diverse in nature. Azo dyescome in about 3000 different variations and are employed in a variety of industries, includingthe textile, leather, paper, and pharmaceutical sectors. But sadly, the majority of azo dyes arepoisonous and mutagenic to all living things. The effluent coming from the textile sector musttherefore be removed and treated. The wastewater is often treated using a variety of physicaland chemical methods, however, these methods have been shown to be inefficient, expensive,produce insufficient amounts of sludge, and have limited effectiveness. So, in order to treatand decolorize dyes and dye-containing effluents without further harming the environment orendangering life forms, It has practically universal dye degradability is economical and hasalso eliminated a number of drawbacks of the physicochemical method. The properties andclassification of azo dyes, associated problems, biodegradation techniques, and possibilitiesare only a few of the subjects covered in this chapter’s examination of recent research,advancements, and the body of existing information on them. Biological processes havereceived special attention as a remedy for the current problems with azo dyes.

Cost-effective microreactors for the synthesis of SnS nanoparticles and inline photocatalytic degradation of azo dyes

A simple wire-assisted cost-effective technique along with a laser assisted rapid microfabrication technique was used for the fabrication of microfluidic reactors to synthesize SnS nanoparticles and study their inline photocatalytic response. The SnS nanoparticles with an average size of 17 nm and optical band gap of 1.25 eV were synthesized using a PDMS based microreactor with a channel diameter of 450 µm. The less expensive PMMA based microreactor coated with SnS nanoparticles was employed in the photocatalytic degradation of EBT dye flowing at the rate of 50 µL/min providing ∼ 75 % instantaneous degradation at a catalyst loading of 30 mg.

Sol-Gel Synthesis of ZnO Nanoparticles Using Different Chitosan Sources: Effects on Antibacterial Activity and Photocatalytic Degradation of AZO Dye

Chitosan was used in the sol-gel synthesis of zinc oxide nanoparticles (ZnO NPs) as a capping agent in order to control the size, morphology, optical bandgap, photocatalytic efficiency, and antimicrobial activity. Different chitosan sources were used for the sol-gel synthesis of ZnO NPs, namely chitosan of shrimp shells, crab shells, and Streptomyces griseus bacteria. The photocatalytic efficiency was studied by using the methylene blue (MB) photodegradation test, and the antibacterial activity of the different types of ZnO NPs was investigated by the agar well diffusion technique. The particle size of ZnO NPs varied between 20 and 80 nm, and the band gap energy ranged between 2.7 and 3.2 eV. Due to the different chitosan sources, the ZnO NPs showed different antibacterial activity against Listeria innocua, Bacillus Subtiliis, Staphylococcus Aureus, Salmonella Typhimurium and Pseudomonas Aeruginosa. The ZnO NPs with lower band gap values showed better antibacterial results compared to ZnO NPs with higher band gap values. The MB dye removal of ZnO (shrimp shells), ZnO (crab shells), and ZnO (Streptomyces griseus) reached 60%, 56%, and 44%, respectively, at a contact time of 60 min, a low initial MB dye concentration of 6 × 10−5 M, a solution temperature of 25 °C, and a pH = 7.

Light-driven biodegradation of azo dyes by Shewanella decolorationis-CdS biohybrid in wastewater lacking electron donors.

The lack of electron donors prevents the effective degradation of azo dyes by bacteria, which severely limits the practical application of conventional biological treatment. Herein, we innovatively designed a bio-photoelectric reduction degradation system composed of CdS and Shewanella decolorationis, which could effectively degrade amaranth in anaerobic conditions driven by light when electron donors were unavailable. Compared with bare S. decolorationis and S. decolorationis (heat-killed)-CdS biohybrid, S. decolorationis-CdS biohybrid had 39.36-fold and 3.82-fold higher first-order kinetic constants, respectively. The morphology, particle size, elemental composition, crystalline type, photovoltaic properties, and band structure of the nanoparticles synthesized by S. decolorationis were carefully examined and analyzed. Light-driven biodegradation experiments showed that amaranth was degraded by the synergy of CdS and S. decolorationis. Reductive degradation of amaranth by electrons was demonstrated by electron and hole trapping. The effect of potential coexisting contaminants, which might serve as hole scavengers, on the degradation of amaranth was evaluated. Membrane protein inhibition experiments also suggested that NADH dehydrogenase, menaquinone, and cytochrome P450 played an important role in electron transfer between CdS and Shewanella decolorationis. The cyclic conversion of NAD+/NADH was probably the most critical rate-limiting step. Electrochemical measurements suggested that faster electron transfer might facilitate the degradation of amaranth. Our findings might contribute to the degradation of azo dyes in wastewater lacking electron donors and deepen our recognition of the microbe-material interface. KEY POINTS: • A BPRDS was constructed with Shewanella decolorationis and CdS. • Amaranth was effectively degraded by BPRDS in anaerobic conditions driven by light. • NDH, MQ, and CYP450 were involved in electron transfer.

The Influence of Support Materials on The Photo-Fenton-like Degradation of Azo Dye Using Continuous Nanoparticles Fixed-bed Column

This study used a continuous photo-Fenton-like method to remediate textile effluent containing azo dyes especially direct blue 15 dye (DB15). A Eucalyptus leaf extract was used to create iron/copper nanoparticles supported on bentonite for use as catalysts (E@B-Fe/Cu-NPs). Two fixed-bed configurations were studied and compared. The first one involved mixing granular bentonite with E@B-Fe/Cu-NPs (GB- E@B-Fe/Cu-NPs), and the other examined the mixing of E@B-Fe/Cu-NPs with glass beads (glass beads-E@B-Fe/Cu-NPs) and filled to the fixed-bed column. Scanning electron microscopy (SEM), zeta potential, and atomic forces spectroscopy (AFM) techniques were used to characterize the obtained particles (NPs). The effect of flow rate and DB15 concentration on the photo-Fenton-like degradation of DB15 in continuous fixed-bed systems was investigated. To optimize both studied systems, the response surface methodology using the central composite design (CCD) was used. The analysis shows that the removal efficiency for GB-E@B-Fe/Cu-NPs was 81% and for glass beads-E@B-Fe/NPs was 62.6%.

Construction of various morphological ZnO-NiO S-scheme nanocomposites for photocatalytic dye degradation

The textile industry has a global environmental impact because of its discharge or dumping of wastewater into rivers, which has a significant impact on water resource quality. The removal of pollutant dyes from water using simple and efficient procedures is gaining interest worldwide. Hence, herein, a simple one-pot solvothermal technique is used to create various types of ZnO/NiO hierarchical nanostructures for photocatalytic dye degradation. Alcoholic solvents, such as ethanol, methanol, and propanol, were utilized for the formation of these nanostructures. The production of porous, marigold-like structures was observed through a morphological investigation. Appropriate characterization techniques were used to investigate the absorptivity, chemical composition, elemental state, crystallinity, and recombination rate. The porous flower-like structure with unique exciton acquisition demonstrated 82 % azo dye degradation, which was ∼ 3 and 2.5 times greater than those using pure ZnO and NiO structures, respectively. Reduced charge carrier recombination, rapid migration of produced electrons to the catalyst surface, and a mounted heterojunction across the interface contributed to this outstanding performance. Furthermore, the composite demonstrated remarkable reusability, retaining a dye degradation efficiency of 74 % after ten cycles. The nanostructure and remarkable dye-degrading capability of the synthesized composites demonstrate that they are suitable for photocatalysis applications.

Kinetic and Mechanistic Study of Oxidative Degradation and Detoxification of Fast Yellow Azo Dye Using Surfactant Assisted Ir-Ni Bimetallic Nanocatalyst

Aim: Catalytic degradation of azo dye. Background: Azo dyes are toxic agents and pollutants and the degradation of these dyes has an important application in the treatment of textile industry wastes. Catalytic decolorization of fast yellow dye by hexacyanoferrate (III), abbreviated as HCF(III) using polyvinylpyrrolidone abbreviated as PVP stabilized Ir-Ni bimetallic nanocrystals has been evaluated by kinetic spectrophotometric method at 440nm wavelength of the reaction mixture. Methods: The impact of various operational factors such as fast yellow dye abbreviated as [FY], oxidant [HCF(III)] ions, promoter iridium-nickel bimetallic nanoparticles abbreviated as [(Ir-Ni)] BMNPs, and solution pH on the rate of the reaction have been examined. Results: The results represent that the reaction follows first -order kinetics model with respect to [oxidant] at optimum pH 8 and fix temperature 40±0.1◦C. Thermodynamic parameters such as activation energy (Ea), enthalpy (ΔH#), entropy (ΔS#), frequency factor (A), and free energy of activation (ΔF#) have been evaluated by examining the reaction rate at four temperatures i.e. 40⁰C, 45⁰C, 50⁰C, and 55⁰C. On the basis of experimental outcomes, an appropriate mechanism involving complex formation has been proposed. Conclusion: Analytical techniques such as UV-Vis spectroscopy, FTIR, and LCMS of degraded products represent the formation of easier and less harmful compounds.

Z-scheme photocatalysis and photoelectrochemical platform with a Co3O4-CuO heterogeneous catalyst for the removal of water pollutants and generation of energy

Protection of the environment by increasing the use of renewable energy sources has become a global priority. The use of renewable resources to generate green energy and remove contaminants from water is an ongoing endeavor. Excellent dye degradation and water-splitting performances have been achieved using photocatalysis, a green technology, combined with the use of heterojunction nanocomposites fabricated with urchin-like and spherical morphologies (Co3O4:CuO). In this study, a one-pot solvothermal approach was used to fabricate a Co3O4–CuO heterojunction composite for use as a multifunctional substrate in dye degradation and photoelectrochemical (PEC) water splitting. For dye degradation, the weight percentage of CuO was adjusted against that of Co3O4; the fabricated CuO–Co3O4 (7.5 wt%) catalyst facilitated 82% degradation of azo dye within only 2 h. The improved catalyst was also used to degrade rhodamine B (76%), methylene blue (71%), and methyl orange (79%). Moreover, owing to its excellent photogenerated charge transfer kinetics and separation capability, the Co3O4–CuO photoelectrode exhibited a higher photocurrent density than the pristine materials in PEC water splitting. Linear sweep voltammetry under light illumination revealed that the photoresponse current of the multifunctional Co3O4–CuO composite was 6.05 mA/cm2 at a potential of 1.8 V (vs. Ag/AgCl), which is ∼2.01 and 3.1 times higher than those of pristine Co3O4 and CuO catalysts, respectively. The photocurrent response of the composite was 3.9 times higher than that under dark conditions. The substantial advantages offered by the fabricated composite over the pristine materials (Co3O4 and CuO), as well as its degradation and PEC water splitting capabilities, were attributed to the combined impact of numerous reactive sites, effective charge separation, increased light harvesting, and facile reactant transfer. Consequently, our research provides novel insights into the fabrication of unique binary nanocomposites with multiple applications and outstanding photocatalytic performance.

Low power photo-assisted catalytic degradation of azo dyes using 1-D BiOI: Optimization of the key physicochemical features

Flower-like spherical 1-D-BiOI nanoparticles were solvothermally synthesized and evaluated for the photocatalytic degradation of the azo dyes Methyl Orange (MO), Methylene Blue (MB), and Eriochrome Black-T (EBT) using ultra-low-power LED light. The soft white-light bulb positively affected the photo-assisted remediation efficiency. The tests showed that 1-D-BiOI removal efficiency against 12 mg/L dyes MO, MB, and EBT were 47.4, 66.1, and 86.7%, respectively. The optimum experimental parameters were determined by modeling and optimization using RSM. Scavenging tests indicated that •OH are the main responsible species. COD was increased initially during light irradiation and then decreased by dye mineralization.

Novel ZnO-biochar nanocomposites obtained by hydrothermal method in extracts of Ulva lactuca collected from Black Sea

The aqueous extract of Ulva lactuca, obtained from algae waste, has been used both as precursor for nanobiochar and source of phycocolloids, for obtaining of ZnO@C composites by hydrothermal method, through two synthesis routes, and capped ZnO nanopowders. The nanomaterials were characterized by XRD, SEM, thermal analysis, UV–vis, PL and FTIR spectroscopy. The presence of ZnO with hexagonal wurtzite structure was confirmed by XRD, while the presence of biochar and capping molecules was confirmed by FTIR spectroscopy and thermal analysis correlated with the total organic carbon determination. The band gap energy was calculated from diffuse reflectance spectra. The photocatalytic properties were tested in the degradation of Congo red azo dye under UV and visible light irradiations, the prepared zinc oxide-biochair nanocomposites demonstrating a good photocatalytic activity, superior to the pristine ZnO nanopowders obtained in similar conditions. The results confirmed a good fit with the Langmuir–Hinshelwood kinetic model. A correlation between photoluminescent and photocatalytic properties of nanomaterials was done. The properties of ZnO@C nanocomposites depended on the synthesis route were compared with those of capped and pristine ZnO samples.