Microwave-assisted sol–gel synthesis of Fe2.9O4/ZnO core/shell nanoparticles using ethylene glycol and its use in photocatalytic degradation of 2-nitrophenol

The MIL100(Fe)/BaTi0.85Zr0.15O3 nanocomposite with the photocatalytic capability for study of tetracycline photodegradation kinetics

The visible light-active nanocomposite with the photocatalytic capability was facile one-pot solvothermal method successfully synthesized. X-ray diffraction (XRD), Thermogravimetry and Derivative Thermogravimetry (TG-DTG), Scanning Electron Microscopy with Energy Dispersive X-ray Analysis (SEM-EDX), Diffuse Reflectance Spectroscopy (UV-Vis DRS), and Fourier Transform Infra-Red (FT-IR) analysis were employed to characterize the synthetized BaTi_0.85Zr_0.15O3, MIL-100(Fe), and the MIL-100(Fe)/BaTi_0.85Zr_0.15O₃ samples. As a result of the Scherrer equations, the size of grains for MIL-100(Fe), BaTi_0.85Zr_0.15O₃, and MIL-100(Fe)/BaTi_0.85Zr_0.15O₃ was estimated to be 40.81, 12.00, and 22.70 nm, respectively. MIL-100(Fe), BaTi_0.85Zr_0.15O₃, and MIL-100(Fe)/BaTi_0.85Zr_0.15O₃ samples showed bandgap values of 1.77, 3.02, and 2.56 determined from their absorption edge wavelengths. In the photodegraded solutions, chemical oxygen demand (COD) data and tetracycline (TC) absorbencies were used to obtain the rate constants of 0.032 min^-1 and 0.030 min^-1, respectively. This corresponds to t_1/2-values of 27.7 min and 21.7 min, respectively, for the degradation and mineralization of TC molecules during photodegradation process.

Cefotaxime degradation by the coupled binary CdS-PbS: characterization and the photocatalytic process kinetics

Increased water pollution due to discharging industrial/urban/hospital wastewater has been adopted to introduce/develop novel removal techniques/catalyst/adsorbent. The hexagonal (wurtzite) CdS and the cubic PbS nanoparticles (NPs) were synthesized, coupled, and supported onto clinoptilolite NPs (CNP). Then, the sample was characterized by X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (DRS), Fourier transform infrared (FTIR), and a scanning electron microscope equipped with an energy dispersive X-ray analyzer (SEM-EDX) techniques. The average crystallite size for CdS NPs, PbS NPs, CNP, and CdS-PbS/CNP samples was obtained at about 24, 36, 27, and 14 nm using the Scherrer formula value of nanometer, by the W-H formula, 31, 17, 39, and 51, respectively. Only a detectable slope can be observed from the DRS spectra for CdS NPs at 591 nm corresponding to an Eg value of 2.1 eV. PbS NPs have a broad abruption peak that begins from the visible region and extends to the IR region of the light. A boosted photocatalytic activity of the supported binary catalysts towards cefotaxime (CT) was reached. An apparent first kinetic model was reached with a k-value of 0.021 min^-1 corresponding to the t_1/2 value of 33 min. A decreased COD trend for the photodegraded CT solutions was reached, and the chemical oxygen demand (COD) results in the Hinshelwood model showed a k-value of 0.016 min^-1, corresponding to a t_1/2 value of 43 min.

The boosted photocatalytic effects of a zeolite supported CdS towards an antibiotic model pollutant: a brief kinetics study

In recent decades, increased world population and industrial activities explosively polluted our environment, especially the aquatic resources. This requires introducing/developing novel methods to decrease the pollution extent of such resources. Here, the hexagonal (wurtzite) CdS nanoparticles (NPs) were synthesized and supported onto ball-mill prepared clinoptilolite NPs (CNP). Samples were briefly characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope equipped with an energy dispersive X-ray analyzer (SEM-EDX), and diffuse reflectance spectroscopy (DRS) techniques. The average crystallite size for CdS NPs and CdS-CNP samples was estimated to be about 9.0 nm and 12.3 nm (from the Scherrer formula) and about 19.7 and 17.5 nm (from the Williamson-Hall model), respectively. From the DRS spectra, the absorption wavelengths of 595 and 546 nm correspond to band gap energies of 2.08, and 2.27 eV was obtained for CdS NPs and CdS-CNP samples. The samples were then used in the photodegradation of cefotaxime (CT), and the results showed a boosted photocatalytic activity for CdS-CNP rather than CdS NPs. The photodegradation process obeyed the pseudo-first-order kinetic model, and the CdS and CdS-CNP catalysts obtained the k-values of 0.013 min^-1 and 0.023 min^-1. When the photodegraded CT solutions were used in COD experiments, the k-values changed to 0.011 min^-1 and 0.029 min^-1, respectively. The zeolite support is an eco-friendly natural zeolite with abundant deposits in Iran that yields a cost-effective method.

The photocatalytic rate of ZnO supported onto natural zeolite nanoparticles in the photodegradation of an aromatic amine

Aniline and its derivate are critical environmental pollutants, and thus, the introduction of an eco-friendly catalyst for removing them is an important research future. The ZnO supported on the ball-mill prepared clinoptilolite nanoparticles (CNPs) was prepared via an ion-exchange process followed by the calcination process. The amount of loaded ZnO in the ZnO-CNP (CZ) samples varied as 0.54, 0.63, 0.72, and 0.86 meq/g as the Zn(II) concentration in the ion-exchange solution varied from 0.1 to 0.5 M. The ZnO-CNP catalyst was briefly characterized by XRD, FTIR, and DRS techniques. The pHpzc value for the various ZnO-CNPs was about 7.1 that had no change with the ZnO loading. By applying the Scherrer equation on the XRD results, a nano-dimension of about 50 nm was obtained for the catalyst. Bandgap energy of the ZnO-CNP samples was estimated by applying the Kubelka-Munk equation on the DRS reflectance spectra. The value for the CZ2 catalyst was about 3.64 eV. The supported ZnO-CNP sample was then used in the photodegradation of 2,4-dichloroaniline (DCA). Raw zeolite showed a relatively low photocatalytic activity. The degradation efficiency was followed by recording the absorbance of the DCA solution by UV-Vis spectrophotometer. The effects of the essential critical operating factors on the degradation efficiency were kinetically studied by applying the Hinshelwood equation to the results. The ZnO-CNP catalyst with 2 w% ZnO showed the best photocatalytic rate in the optimal conditions of 0.75 g/L, C_DCA: 15 ppm, and the initial pH: 5.8. Finally, HPLC analysis of the blank and the photodegraded DCA solutions at 180 and 300 min confirmed 74 and 87% of DCA molecules were degraded during these times. The results confirm that supported ZnO onto clinoptilolite caused enhanced photocatalytic activity because the zeolite internal electrical field prevents the e^-/h⁺ recombination.

Supported cuprous oxide-clinoptilolite nanoparticles: Brief identification and the catalytic kinetics in the photodegradation of dichloroaniline

The supported CuO onto the ball-mill prepared clinoptilolite nanoparticles (CNPs) was prepared via an ion exchange process in Cu(II) aqueous solution followed by the calcination process. The CuO-CNP samples with various CuO loading were briefly characterized by XRD, FTIR, and DRS. pHpzc was varied in the range of 6.3 to 6.8 depending on the amount of loaded CuO in the samples. The band gap energy was estimated by applying the Kubelka-Munk equation on the DRS results that varied from 2.41 to 2.50 eV depending on the CuO loading. Based on the Scherrer equation nano-sized CuO-CNP at about 50 nm was estimated. The CuO-CNP contained 3.9% CuO showed the highest photocatalytic activity toward dichloroaniline (DCA). The effects of the experimental variables on DCA photodegradation were studied by using the Hinshelwood model. The optimal conditions for obtaining a higher rate for DCA photodegradation were the catalyst dose of 0.5 g/L, C_DCA: 5 ppm, and the initial pH: 3. HPLC analysis of the photodegraded DCA solutions for 180 and 300 min gave the degradation extents 71% and 90%, respectively.