Core-shell structured epoxide functional NiO/SiO2 nanocomposite particles and photocatalytic decolorization of congo red aqueous solution

Electrochemical monitoring of congo red degradation using strontium titanate-doped biochar nanohybrids derived photocatalytic plates

Present investigation demonstrates the development and characterization of strontium titanate (SrTiO₃) doped biochar nanohybrid photocatalysts. Biochar nanohybrid was synthesized using an ultrasonic-assisted dispersion technique, which involved dispersing SrTiO₃ nanoparticles into activated biochar at a weight ratio of 1:2 (w/w) under ambient conditions. The development of the biochar nanohybrid was verified through a comprehensive analysis of their spectral, microstructural, thermal, electrical, and electrochemical properties. The scanning electron microscopy analysis reveals a surface-associated multiphase morphology of the biochar nanohybrid, attributed to the uniform distribution of SrTiO₃ within the activated biochar matrix. Biochar nanohybrid exhibited a reduced optical band gap of 2.77 eV, accompanied by a crystallite size of 32.45. Thermogravimetric analysis revealed the thermal stability of the biochar nanohybrid, as evidenced by a char residue of 70.83% at 1000 °C. The working electrodes derived from biochar nanohybrid have exhibited ohmic behavior and displayed a significantly enhanced DC conductivity (mS/cm) of 1.13, surpassing that of activated biochar (0.53) and SrTiO₃ (0.62) at 100 V. The developed biochar nanohybrid were employed for the degradation of congo red dye by exposing the dye solution to photocatalytic plates. These photocatalytic plates were prepared by coating biochar nanohybrid onto glass plates using epoxy-based reactive binders for secure binding. The photodegradation of congo red was evaluated through cyclic voltammetric analysis in a 0.1 M KCl solution at pH 8.0, resulting in an impressive 99.95% photocatalytic efficiency in degrading a congo red solution (50 mg/L). This study presents a novel approach for the fabrication of biochar nanohybrid-derived photocatalytic plates, offering high photocatalytic efficiency for the degradation of congo red dye.

Chitosan-capped ternary metal selenide nanocatalysts for efficient degradation of Congo red dye in sunlight irradiation

Wastewater emerging from the industries containing organic pollutants is a severe threat to humans' health and aquatic life. Therefore, the degradation of highly poisonous organic dye pollutants is necessary to ensure public health and environmental protection. To tackle this problem, visible-light-driven ternary metal selenide nanocomposites were synthesized successfully by the solvothermal method and supported by chitosan microspheres (FeNiSe-CHM). The prepared nanoparticles were capped in chitosan microspheres to avoid leaching and facilitate easy recovery of the catalyst. FTIR spectrum confirmed the synthesis of nanocomposite and nanocomposite-chitosan microspheres (FeNiSe-CHM). Based on the SEM images, the nanomaterial and FeNiSe-CHM has an average particle size of 64 nm and 874 μm, respectively. The presence of iron, nickel and selenium elements in the EDX spectrum revealed the synthesis of FeNiSe-NPs. XRD analysis determined the crystallite structure of nanocomposites as 14.2 nm. The photocatalyst has a crystalline structure and narrow bandgap of 2.09 eV. Moreover, the as-synthesized FeNiSe-CHM were employed for the photodegradation of carcinogenic and mutagenic Congo red dye. The catalyst microspheres showed efficient photocatalytic degradation efficiency of up to 99% for Congo red dye under the optimized conditions of 140 min, pH 6.0, dye concentration 60 ppm and catalyst dose of 0.2 g in the presence of sunlight irradiation following the second-order kinetics. After five consecutive cycles, it showed a slight loss in the degradation efficiency. In conclusion, the results demonstrate a high potential of chitosan-based ternary metal selenide nanocomposites for abatement of dye pollutants from the industrial wastewater.

Nickel-Modified TS-1 Catalyzed the Ammoximation of Methyl Ethyl Ketone

In this paper, five kinds of transition metal-modified titanium silicalite-1 (M-TS-1) were prepared by an ultrasonic impregnation method. We studied their catalytic performances in the ammoximation of methyl ethyl ketone (MEK). The various M-TS-1 catalysts revealed distinct differences in their MEK ammoximation activity. The nickel-modified TS-1 (Ni-TS-1), especially 3 wt % Ni-TS-1, exhibited a satisfactory conversion of MEK (99%) associated with a high selectivity of methyl ethyl ketoxime (MEKO) (99.3%), which was 6% higher than that of TS-1 under the same conditions. Moreover, the catalyst showed excellent recyclability and the reactivity could be completely recovered after regeneration. The catalysts were characterized by Powder X-ray Diffraction (XRD), Fourier Transformed Infrared Spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), and so on. It was demonstrated that the skeleton structure of TS-1 was basically maintained and the electron environment of the Ti active site was changed after the nickel modification, which can optimize the adsorption capacity and the activation for H2O2. Meanwhile, the surface nickel species reduced the surface acidity of the catalyst, which provided an appropriate pH and inhibited the deep oxidation of oxime.

ZnO/ZrO2 nanocomposite: Sonosynthesis, characterization and its application for wastewater treatment

ZnO/ZrO₂ nanocomposites with different ZnO: ZrO₂ molar ratios (2:1, 1:1, and 1:2)were prepared by sol gel approach under ultrasonic irradiation. For preparation of the nano-composites, the ZnO gel was directly incorporated into the ZrO₂ gel at different molar ratios. The reaction mixture was stirred continuously for two days and then it was ultrasonoicated for 30min. The filtrated composite gel was washed, and then calcinated at 300°C in furnace for 3h. X-ray powder diffraction patterns exhibited well-formed crystal structures and pure crystalline phases in the synthesized nanoparticles (NPs). The FT-IR analyses indicated that the positions of peaks related to Zn-O and Zr-O absorption bands did not change in nano-composites. In addition, FESEM images indicated uniform spherical morphology of the NPs. The highest photo-degradation performance of Congo red (as a model water pollutant) was obtained by 1:2molar ratio of ZrO₂: ZnO in the nano-composite. The particle size and band gap were considered as important factors on nano-catalysts performance. Furthermore, the effects of ultrasonic irradiation, pH, and the concentration of pollutant in solution were investigated on photocatalytic performance of optimum nanocomposite.