Efficient photo-catalytic degradation of malachite green using nickel tungstate material as photo-catalyst

Biosynthesis of CoCr2O4/ZnO nanocomposites using Basella alba L. leaves extracts with enhanced photocatalytic degradation of malachite green in aqueous media

The use of chemical materials to tackle environmental concerns has undergone significant evolution, particularly in the pursuit of strategies for removing pollutants from wastewater as part of environmental remediation an increasingly crucial research topic. Employing green photocatalysts stands out as an efficient and cost-effective approach, playing a key role in promoting sustainable environmental remediation. This study introduces the modification of zinc oxide with cobalt chromite (CoCr2O4/ZnO) through a green synthesis method employing Basella alba L. leaves extract (BALE). Utilizing various characterization techniques, including FT-IR, UV-Vis DRS, XRD, SEM-EDS, and TEM, key features of ZnO, CoCr2O4, and CoCr2O4/ZnO nanocomposites were identified. The optical band gaps for ZnO, CoCr2O4, and CoCr2O4/ZnO nanocomposites were determined as 3.16, 1.71, and 2.80 eV, respectively, where it was shown that the band gap of the ZnO was reduced significantly. CoCr2O4/ZnO nanocomposites displayed a cubic shape of CoCr2O4 on the surface of ZnO, with a particle size of 23.84 ± 8.08 nm. The photocatalytic activity was assessed through the degradation of malachite green under visible light irradiation, where the CoCr2O4/ZnO nanocomposites exhibited superior photodegradation efficiency at 90.91%, surpassing ZnO alone (57.09%). This improvement in photocatalytic activity is attributed to a reduced band gap energy and a high rate constant value of 9.57 × 10-3 min-1, demonstrating pseudo-first-order reaction kinetics. In summary, this research presents the development of a ZnO-based photocatalyst with exceptional performance, especially in the visible light spectrum, making it a promising candidate for applications in wastewater removal.

Preparation of Bismuth Tungstate Nanomaterials with Different Morphologies and Their Effect on Exercise Rehabilitation of Patients with Lumbar Disc Herniation

It is understood that the effect of exercise rehabilitation drugs in patients with lumbar disc herniation is poor. Some studies have shown that bismuth tungstate nanomaterials with certain morphology can treat the exercise rehabilitation of patients with lumbar disc herniation. In order to help patients with lumbar disc herniation to a certain extent, in this paper, bismuth tungstate nanomaterials with different structures and morphologies were prepared by hydrothermal method, and viscous tungsten nanomaterials with different structures and morphologies were prepared by adjusting the pH value of the solution and the concentration of CTAB. In this paper, the structure and morphology of tungsten samples with different structure and morphology were characterized by CTAB X-ray (XRD) deflection and FESEM. It was found that the morphology of the samples changed after adding 0.02 mol/L surfactant CTAB in the reaction system, and when the concentration of CTAB was 0.04 mol/L, the nanotubes were stacked together under the action of surfactant. When the concentration of CTAB increased to 0.06 mol/L, the self-assembled nanocomposites tended to be petal like.

Comparative studies on adsorptive and photocatalytic potential of differently synthesized ferric oxide nanoparticles for malachite green

In the present work, effect of different fuels on the structural, morphological, magnetic, adsorptive and photocatalytic properties of ferric oxide nanoparticles (Fe₂O₃ NPs) was evaluated. Fe₂O₃ NPs were synthesized via combustion method by using oxalyl dihydrazide (ODH), polyethylene glycol (PEG) and urea as fuels. The indigenously synthesized NPs were characterized by different analytical tools. XRD patterns confirmed the presence of α- and γ-Fe₂O₃ phases. TEM micrographs displayed average particle size was less than 30 nm. Saturation magnetization amplified with increase in the γ-Fe₂O₃ content, which was correlated to the fuel used for synthesis. Adsorptive and photocatalytic activity of synthesized NPs was studied using malachite green (MG) dye as a model compound. The uptake behavior for MG dye was influenced by the solution pH, contact time, adsorbent dose, temperature and dye concentration. Thermodynamic studies indicated the endothermic nature of the adsorption phenomenon. The adsorption was well defined with Langmuir and Freundlich isotherms in comparison to Dubinin-Radushkevitch adsorption isotherm model. The trend for percentage removal of MG dye using NPs synthesized by different fuels was: urea > PEG > ODH. Fe₂O₃ NPs facilitated photo degradation of dye solution in ultra-violet and visible light irradiations.

Oxygen doping through oxidation causes the main active substance in g-C3N4 photocatalysis to change from holes to singlet oxygen

Improving the photocatalytic activity of graphitic carbon nitride (g-C₃N₄) for organic pollutant removal from water and in-depth study of the effect of oxygen doping on its photocatalytic mechanism are deserving of research attention. Oxygen-doped g-C₃N₄ with a suitable degree of oxidation was prepared by oxidation using concentrated acid-ultrasound double oxidation. Oxygen doping by oxidation changed the physical and chemical properties of g-C₃N₄, and improved its rhodamine B photocatalytic degradation efficiency. The physical and chemical properties of g-C₃N₄ were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and zeta potential analysis, among other methods. The photocatalytic mechanism was also studied in depth using photoluminescence, electrochemical impedance spectroscopy, transient photocurrent measurements, diffuse reflectance spectroscopy, and Mott-Schottky plots. An appropriate degree of oxidation introduced pit-like defects rich in oxygen-containing functional groups onto the g-C₃N₄ surface, which improves its photocatalytic performance. Furthermore, in the photocatalytic process of oxidized g-C₃N₄, oxygen doping was confirmed to change the main active substance of g-C₃N₄ photocatalysis from holes to singlet oxygen. This study provides an in-depth explanation of the photocatalytic mechanism of g-C₃N₄ doped with oxygen, which provides guidance and reference for the design of photocatalysts for organic pollutant removal from water and the analysis of photocatalytic mechanisms for water treatment.

Synthesis, Antimicrobial Activity, and Photocatalytic Performance of Ce Doped SnO2 Nanoparticles

This work represented the synthesis of Ce doped SnO2 nanoparticles by a wet chemical method and was characterized by various characterization techniques. PXRD confirmed the presence of the rutile phase for Ce doped SnO2 nanoparticles. SEM image and elemental mapping showed agglomerated irregular shaped particles and uniform distribution of 5% Ce ions within the SnO2 lattice, respectively. Ce doped SnO2 nanoparticles showed antimicrobial activity against E. coli and prevented the growth of bacteria. The nanoparticles were found photocatalytic active and photocatalytic behavior was elucidated by the degradation of Malachite Green dye under UV light irradiation.

Selenium vacancies enriched the performance of supercapacitors with excellent cycling stability via a simple chemical bath deposition method

Herein, we report a simple and cost-effective route for the fabrication of NiWO₄, NiWO₄P, and NiWO₄Se nanostructures using the chemical bath deposition method.