Synthesis, characterization of porphyrin and CdS modified spherical shaped SiO2 for Reactive Red 120 degradation under direct sunlight

Zeolite 13X incorporated with Zn-Ce oxide nanocatalyst for removal of Reactive Red 120 dye: RSM-based approach

In this study, the photocatalytic removal of Reactive Red 120 (RR120) dye was examined using zeolite 13X incorporated with Zn-Ce under UV irradiation. The synthesis of Zn-Ce nanoparticles incorporated with zeolite 13X was conducted through the co-precipitation method, and the features of the prepared nanocatalyst were analyzed using various techniques. The SEM and BET analyses indicated successful incorporation of ZnO-Ce oxides on the surface of zeolite 13X and a specific surface area of 359.39 m2/gm, respectively. Further, the average size of crystal grains was 28 nm. The response surface methodology (RSM) approach was employed to optimize operating parameters. The quadratic model suggested by the RSM approach, characterized by a high regression coefficient (R2 = 0.9632), indicates a high level of reliability. Moreover, under optimal conditions (catalyst loading of 4 mg, pH of 3, H2O2 amount of 0.2 mL, UV power of 25 W, and reaction time of 60 min), the highest RR120 dye removal percentage was 99.97%. Kinetic data indicated an increase in the reaction rate constant from 0.0631 to 0.1796 min-1. The zeolite 13X incorporated with Zn-Ce photocatalyst exhibited excellent stability over 5 cycles, with only a 5.50% decrease in RR120 dye removal yield. This study demonstrates the promising potential of zeolite 13X incorporated with Zn-Ce nanoparticles for the removal of RR120 dye from aqueous suspension.

Nanostructured Aluminum Oxyhydroxide-A Prospective Support for Functional Porphyrin-Based Materials

A method for the grafting of unsymmetrical A2BC-type 5,15-bis(4-butoxyphenyl)-10-(4-carboxyphenyl)-20-(phenanthrenoimidazolyl)-porphyrin onto the surface of nanostructured aluminum oxyhydroxide modified with a single SiO2 layer (NAOM) was successfully developed. A straightforward procedure towards surface modification of NAOM allowed us to prepare a new porphyrin-containing hybrid material. The obtained 3D heterostructure was extensively characterized using XPS, TEM and diffuse reflectance spectroscopy. Structural and morphological peculiarities of the inorganic support before and after the immobilization procedure were studied and discussed in detail. The stability of the material against leaching and the porphyrin immobilization ratio ca. 14% by weight were also revealed.

Enhanced photocatalytic degradation of Reactive Red 120 dye under solar light using BiPO4@g-C3N4 nanocomposite photocatalyst

Azo dyes such as Reactive Red 120 raise great concerns about their increased harmfulness. Photocatalytic degradation is considered to be one of the most efficient techniques for Reactive Red 120 degradation. Herein, a highly solar active graphitic carbon nitride-assisted bismuth phosphate nanocomposite (BiPO₄@g-C₃N₄) was synthesized by the thermal decomposition of melamine followed by the co-precipitation method. Various analytical techniques were utilized to characterize the prepared BiPO₄, g-C₃N₄, and BiPO₄@g-C₃N₄ nanocomposites. Scanning electron microscopy (SEM) shows the nanorods and particle morphology of the bare BiPO₄ and g-C₃N₄ respectively. Furthermore, the optical band gap energies of the BiPO₄, g-C₃N₄, and BiPO₄@g-C₃N₄ nanocomposite have been calculated to be 4.20, 2.66, and 2.68 eV respectively. Under sunlight, the BiPO₄@g-C₃N₄ nanocomposite showed higher photocatalytic activity towards the degradation of RR120. The BiPO₄@g-C₃N₄ nanocomposite efficiently degrades the RR120 under sunlight with a higher first-order reaction rate constant of 0.0145 min^-1. This is seven times higher than that of bare BiPO₄ (0.0019 min^-1) nanorods and four times greater than g-C₃N₄ (0.0036 min^-1). The photocatalytic efficiency was found to be maximum at pH 4 and decreased as the pH of the solution increased. Even after five recycle runs, the catalyst performance of the RR120 dye has decreased by less than 5%, indicating the high stability of the BiPO₄@g-C₃N₄ nanocomposite. Furthermore, the radical trapping experiment demonstrates that the active species in the dye degradation process are holes and hydroxide radicals. The photocatalytic mechanism was proposed for the BiPO₄@g-C₃N₄ nanocomposite and further validated by the electrochemical impedance spectroscopy analysis.

Designing Novel Strategy to Produce Active Nanohybrids in Sunlight for Purification of Water Based on Inorganic Nanolayers, Magnetic Nanocomposites and Organic Species

Energy and water related problems have attracted strong attention from scientists across the world because of deficient energy and water pollution. Following this line, new strategy depended on preparing nanolayers of Al/Zn and magnetic nanoparticles of cobalt iron oxides nanocomposite in addition to long chains of hydrocarbons of stearic acid to be used as roofs, fillers and pillars; respectively, to design optical-active nanohybrids in sunlight for removing the colored pollutants from water in few minutes. By using long chains of hydrocarbons of stearic acid, X-ray diffraction (XRD) results and TEM images showed expansion of the interlayered spacing from 0.76 nm to 2.02 nm and insertion of magnetic nanoparticles among the nanolayers of Al/Zn. The optical properties and activities showed that the nanohybrid structure based on zinc oxide led to clear reduction of the band gap energy from 3.3 eV to 2.75 eV to be effective in sunlight. Photocatalytic degradation of the dye of acid green 1 confirmed the high activity of the prepared zinc oxide nanohybrids because of a complete removal of the dye after ten minutes in sunlight. Finally, this strategy was effective for producing photo-active nanohybrids for using renewable and non-polluting energy for purifying water.

Design and Preparation of Biomass-Derived Activated Carbon Loaded TiO2 Photocatalyst for Photocatalytic Degradation of Reactive Red 120 and Ofloxacin

The design and development of novel photocatalysts for treating toxic substances such as industrial waste, dyes, pesticides, and pharmaceutical wastes remain a challenging task even today. To this end, a biowaste pistachio-shell-derived activated carbon (AC) loaded TiO₂ (AC-TiO₂) nanocomposite was fabricated and effectively utilized towards the photocatalytic degradation of toxic azo dye Reactive Red 120 (RR 120) and ofloxacin (OFL) under UV-A light. The synthesized materials were characterized for their structural and surface morphology features through various spectroscopic and microscopic techniques, including high-resolution transmission electron microscope (HR-TEM), field emission scanning electron microscope (FE-SEM) along with energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, photoluminescence spectra (PL) and BET surface area measurements. AC-TiO₂ shows enhanced photocatalytic activity compared to bare TiO₂ due to the change in the bandgap energy and effective charge separation. The degradation rate of dyes was affected by the bandgap of the semiconductor, which was the result of the deposition weight percentage of AC onto the TiO₂. The presence of AC influences the photocatalytic activity of AC-TiO₂ composite towards RR 120 and OFL degradation. The presence of heteroatoms-enriched AC enhances the charge mobility and suppresses the electron-hole recombination in AC-TiO₂ composite, which enhances the photocatalytic activity of the composite. The hybrid material AC-TiO₂ composite displayed a higher photocatalytic activity against Reactive Red 120 and ofloxacin. The stability of the AC-TiO₂ was tested against RR 120 dye degradation with multiple runs. GC-MS analyzed the degradation intermediates, and a suitable degradation pathway was also proposed. These results demonstrate that AC-TiO₂ composite could be effectively used as an ecofriendly, cost-effective, stable, and highly efficient photocatalyst.