nitrophenols and methyl-orange

In this study, tin oxide‑cobalt oxide nanocatalyst was prepared by a simple method, which grew in spherical particles with an average diameter of 30 nm. Tin oxide-cobalt oxide was further wrapped in alginate polymer hydrogel (Alg@tin oxide-cobalt oxide), and both materials were utilized as nanocatalysts for the catalytic transformation of different pollutants. Tin oxide-cobalt oxide and Alg@tin oxide-cobalt oxide nanocatalysts were tested for the catalytic reduction of 4-nitrophenol, congo red, methyl orange, methylene blue (MB) and potassium ferricyanide in which sodium borohydride was used as a reducing agent. Tin oxide-cobalt oxide and Alg@tin oxide-cobalt oxide nanocatalysts synergistically reduced MB in shorter time (2.0 and 4.0 min) compared to other dyes. The reduction conditions were optimized by changing different parameters. The rate constants for MB reduction were calculated and found to be 1.5714 min

Topics: Alginates; Azo Compounds; Borohydrides; Catalysis; Cobalt; Congo Red; Ferricyanides; Kinetics; Methylene Blue; Nanocomposites; Nanotechnology; Nitrophenols; Oxidation-Reduction; Oxides; Tin Compounds; Wastewater; Water Pollutants, Chemical; Water Purification

Topics: Azo Compounds; Biomass; Catalysis; Congo Red; Environmental Pollutants; Lignin; Metal Nanoparticles; Methylene Blue; Models, Chemical; Nitrophenols

In the present work, we demonstrated the biosynthesis of silver nanoparticles (AgNPs) by highly stable, economic and eco-friendly method using leaf extract of Terminalia arjuna (T. arjuna) and employing as a catalyst for the degradation of methyl orange (MO), methylene blue (MB), congo red (CR) and 4- nitrophenol (4-NP). The biosynthesis of AgNPs was visually validated through the appearance of reddish-brown color and further confirmed by the UV-spectra at 418 nm. The TEM and FE-SEM studies revealed the spherical shape of particles with size ranged between 10-50 nm. Face centered cubic crystalline nature of AgNPs was proved by XRD analysis. The negative value of zeta potential (-21.7) indicated the stability of AgNPs and elemental composition was confirmed by EDS. FT-IR analysis revealed the functional groups present in the plant extract trigger the biosynthesis of AgNPs. The AgNPs exhibited strong degradation of MO (86.68%), MB (93.60%), CR (92.20%) and 4NP (88.80%) by completing the reduction reaction within 20 min. The reaction kinetics followed the pseudo-first-order and displayed k-values (rate constant) 0.166 min

Topics: Azo Compounds; Catalysis; Coloring Agents; Congo Red; Methylene Blue; Nanoparticles; Nitrophenols; Plant Extracts; Plant Leaves; Silver; Terminalia

This study presents an efficient and facile method for biosynthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using aqueous extract of burdock root (BR), A. lappa, and their applications. The nanoparticles were characterized by ultraviolet-visible spectrophotometry, X-ray diffraction, transmission electron microscopy, energy dispersive X-ray, thermogravimetry, and differential thermal analysis. AgNPs capped the BR extract (BR-AgNPs) possessed roughly spherical geometry with an average diameter of 21.3 nm while uneven geometry of AuNPs capped the BR extract (BR-AuNPs) showed multi shapes in average size of 24.7 nm. The BR-AgNPs strongly inhibited five tested microorganism strains. In particular, the nanoparticles showed excellent catalytic activity for the conversion of pollutants within wastewater. Pseudo-first-order rate constants for the degradation of 4-nitrophenol, methyl orange, and rhodamine B were respectively found 6.77 × 10

Topics: Anti-Infective Agents; Arctium; Azo Compounds; Catalysis; Gold; Metal Nanoparticles; Microbial Sensitivity Tests; Microscopy, Electron, Transmission; Nitrophenols; Plant Extracts; Rhodamines; Silver; Spectrophotometry, Ultraviolet; Thermogravimetry; Water Pollutants, Chemical; X-Ray Diffraction

Topics: Azo Compounds; Catalysis; Coloring Agents; Congo Red; Green Chemistry Technology; Metal Nanoparticles; Methylene Blue; Nanotechnology; Nitrophenols; Oxidation-Reduction; Palladium; Plant Extracts; Prunus armeniaca; Rhodamines; Salvia

Our quest for a green, non-toxic and environmentally benign synthetic design for the fabrication of metal nanoparticles has led to the use of essential oil present in plant parts as the bioreductant. In this report, silver particles at nanoscale have been synthesized using essential oil present in the leaves of Coleus aromaticus at physiological pH and at 373 K. UV-vis spectra of the colloid display strong plasmon bands centred around 396-411 nm, characteristic of silver nanoparticles. Comparative studies of the FTIR spectra of essential oil and silver nanoparticles reveal the involvement of terpenes and their phenolic derivatives in reduction and subsequent stabilization. TEM micrographs and XRD pattern show the formation of 26 and 28 nm sized face centred cubic structured crystalline nanospheroids with intermittent formation of nanorods. The phytosynthesized silver nanoparticles are found to be effective in degrading hazardous organic pollutants including methyl orange, methylene blue, eosin yellowish and para nitro phenol within a span of a few minutes. Dose dependant antibacterial activity of the biogenic nanosilver against pathogenic Gramme-negative Escherichia coli (ATCC 25922) and Gramme-positive Staphylococcus aureus (ATCC 25923) has been portrayed through agar-well dispersion method. The antioxidant activity including antiradical activity and reducing power have been depicted through superoxide radical scavenging activity, hydroxyl radical scavenging activity, hydrogen peroxide scavenging activity, nitric oxide scavenging activity, DPPH assay and reducing power activity involving the reduction of ferric ion.

Topics: Anti-Bacterial Agents; Antioxidants; Azo Compounds; Catalysis; Coleus; Eosine Yellowish-(YS); Escherichia coli; Green Chemistry Technology; Metal Nanoparticles; Methylene Blue; Microbial Sensitivity Tests; Nitrophenols; Oils, Volatile; Plant Leaves; Silver; Spectroscopy, Fourier Transform Infrared; Staphylococcus aureus; Superoxides; Water Pollutants, Chemical

Pulsed discharge plasma (PDP) combined with charcoal (PDP-charcoal) was employed to treat dye wastewater, with methyl orange (MO) as the model pollutant. The charcoal was prepared using spent tea leaves and was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and Boehm titration to investigate the adsorption and catalytic characteristics before and after adsorption and PDP treatment. The prepared charcoal exhibited a high MO adsorption capacity, and the adsorption process followed the pseudo-second-order kinetic model and the Freundlich model. The MO decoloration efficiency reached 69.8 % within 7.5 min of treatment in the PDP-charcoal system, whereas values of 29.2 and 25.9 % were achieved in individual PDP and charcoal systems, respectively. The addition of n-butanol and H2PO4 (-) presented inhibitive effects on MO decoloration in the PDP system. However, these effects were much weaker in the PDP-charcoal system. In addition, the effects of charcoal on O3 and H2O2 formation were evaluated, and the results showed that both the O3 and H2O2 concentrations decreased in the presence of charcoal. The MO decomposition intermediates were analyzed using UV-Vis spectrometry and GC-MS. 1,4-Benzoquinone, 4-nitrophenol, 4-hydroxyaniline, and N,N'-dimethylaniline were detected. A possible pathway for MO decomposition in this system was proposed.

Topics: Adsorption; Aminophenols; Azo Compounds; Benzoquinones; Camellia sinensis; Charcoal; Color; Coloring Agents; Hydrogen Peroxide; Kinetics; Microscopy, Electron, Scanning; Nitrophenols; Ozone; Plant Leaves; Spectroscopy, Fourier Transform Infrared; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical

Topics: Adsorption; Aminophenols; Azo Compounds; Catalysis; Cellulose; Chitosan; Coloring Agents; Metal Nanoparticles; Nanocomposites; Nickel; Nitrophenols; Paper

Catalytic activity of Zr and Ag co-doped TiO2 nanoparticles on the reduction of 4-nitrophenol, degradation of methylene blue and methyl orange was studied using sodium borohydride as reducing agent. The nanoparticles were characterized using X-ray diffraction, energy dispersive X-ray, high resolution transmission electron microscopy, selected area electron diffraction and UV-Vis spectroscopy. The rate of the reduction/degradation was found to increase with increasing amount of the photocatalyst which could be attributed to higher dispersity and small size of the nanoparticles. The catalytic activity of Zr and Ag co-doped TiO2 nanoparticles showed no significant difference even after recycling the catalyst four times indicating a promising potential for industrial application of the prepared photocatalyst.

Topics: Azo Compounds; Catalysis; Environmental Pollutants; Light; Metal Nanoparticles; Methylene Blue; Microscopy, Electron, Transmission; Nitrophenols; Oxidation-Reduction; Silver; Spectrometry, X-Ray Emission; Spectrophotometry, Ultraviolet; Titanium; X-Ray Diffraction; Zirconium

The TiO(2)/ZnO nanofibers embedded by Au nanoparticles (TiO(2)/ZnO/Au NFs) were fabricated by combining the electrospinning technique (for TiO(2)/ZnO nanofibers) and an in situ reduction approach (for Au nanoparticles). X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electronmicroscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy, were used to characterize the as-synthesized nanofibers. The results showed that small Au nanoparticles (Au NPs) were well dispersed on the TiO(2)/ZnO nanofibers (TiO(2)/ZnO NFs). And, the TiO(2)/ZnO/Au nanofibers showed high charge separation efficiency under ultraviolet excitation, as evidenced by photoluminescence spectra. The photocatalytic studies revealed that the TiO(2)/ZnO/Au NFs exhibited enhanced photocatalytic efficiency of photodegradation of Methyl orange (MO) and 4-nitrophenol (4-NP) compared with the pure TiO(2) nanofibers, ZnO nanofibers and TiO(2)/ZnO NFs under ultraviolet excitation, which might be attributed to the high separation efficiency of photogenerated electron-hole pairs based on the photosynergistic effect among the three components of TiO(2), ZnO and Au. And, the TiO(2)/ZnO/Au NFs could be easily separated and recycled due to their one-dimensional nanostructural property.

Topics: Azo Compounds; Catalysis; Coloring Agents; Gold; Metal Nanoparticles; Nanofibers; Nitrophenols; Photolysis; Titanium; Ultraviolet Rays; Waste Disposal, Fluid; Zinc Oxide