Decolorization of Orange-G Aqueous Solutions over C60/MCM-41 Photocatalysts

Synergistic impacts of sonolysis aided photocatalytic degradation of water pollutant over perovskite-type CeNiO3 nanospheres

The current study reports on the preparation of perovskite-type CeNiO3 nanostructures as a sonophotocatalyst via a facile hydrothermal approach followed by annealing at 800 °C.

Characterization and performance evaluation of synthesized ZnO nanoflowers, nanorods, and their hybrid nanocomposites with graphene oxide for degradation of Orange G

Nanoflowers and nanorods of ZnO were synthesized via hydrothermal route. These morphologies of zinc oxide (ZnO) were then decorated over graphene oxide (GO) to yield hybrid nanocomposites, namely, GO-ZnO_nR and GO-ZnO_nF. The decoration of ZnO nanorods and nanoflowers on GO layers was confirmed through FESEM images. The synthesized nanocomposites were subjected to degrade the Orange G under identical conditions. The band gap energies determined using diffused reflectance spectra were 2.87, 2.89 eV for GO-ZnO_nR, and GO-ZnO_nF, whereas, for both ZnO_nR and ZnO_nF, it was 3.14 eV. For 50 min of UV irradiations (at 6 pH), 100% degradation was achieved corresponding to GO-ZnO_nR (44.1 m² g^-1) followed by 90.1%, 70.2%, and 68.3% with GO-ZnO_nF (35.9 m² g^-1), ZnO_nR (20 m² g^-1), and ZnO_nF (15.1 m² g^-1), respectively. Significant boost in the degradation of Orange G, with GO-ZnO_nR, was attributed to its reduced band gap, higher surface area, and enhanced charge separation. Kinetic study confirms the pseudo-first-order reaction rate. Mineralization efficiency of 91% in 120 min indicated the efficient reduction of Orange G and its intermediates. Further, reactive species trapping experiments revealed that photo-induced ^•OH are dominant radicals for the degradation followed by ^•O₂^- and h⁺. Liquid chromatography mass spectra data has been used to predict the plausible reaction pathways. Reusability studies indicated that GO-ZnO_nR can be used for four successive degradation cycles, without any significant activity loss.

Recent Progress on Fullerene-Based Materials: Synthesis, Properties, Modifications, and Photocatalytic Applications

Solar light is an inexpensive energy source making up for energy shortage and solving serious environmental problems. For efficient utilization of solar energy, photocatalytic materials have attracted extensive attention over the last decades. As zero-dimensional carbon nanomaterials, fullerenes (C60, C70, etc.) have been extensively investigated for photocatalytic applications. Due to their unique properties, fullerenes can be used with other semiconductors as photocatalyst enhancers, and also as novel photocatalysts after being dispersed on non-semiconductors. This review summarizes fullerene-based materials (including fullerene/semiconductors and fullerene/non-semiconductors) for photocatalytic applications, such as water splitting, Cr (Ⅵ) reduction, pollutant degradation and bacterial disinfection. Firstly, the optical and electronic properties of fullerene are presented. Then, recent advances in the synthesis and photocatalytic mechanisms of fullerene-based photocatalysts are summarized. Furthermore, the effective performances of fullerene-based photocatalysts are discussed, mainly concerning photocatalytic H2 generation and pollutant removal. Finally, the current challenges and prospects of fullerene-based photocatalysts are proposed. It is expected that this review could bring a better understanding of fullerene-based photocatalysts for water treatment and environmental protection.

Nascent Rice Husk as an Adsorbent for Removing Cationic Dyes from Textile Wastewater

We assessed the applicability of rice husk (RH) to remove cationic dyes, i.e., methylene blue (MB) and crystal violet (CV), from water. RH thermally treated at 75 °C showed a higher adsorption capacity than that at high temperatures (300–700 °C). For a suitable CV-adsorption model, a pseudo-first-order model for MB adsorption was followed by the kinetics adsorption process; however, a pseudo-second-order model was then suggested. In the qt versus t1/2 plot, the MB line passed through the origin, but that of CV did not. The Langmuir isotherm model was better than the Freundlich model for both dye adsorptions; furthermore, the adsorption capacity for MB and CV was 24.48 mg/g and 25.46 mg/g, respectively. Thermodynamically, the adsorption of both MB and CV onto the RH was found to be spontaneous and endothermic. This adsorption increased insignificantly on increasing the solution pH from 4 to 10. With an increasing dosage of the RH, there was an increase in the removal percentages of MB and CV; however, adsorption capacity per unit mass of the RH was observed to decrease. Therefore, we conclude that utilizing RH as an available and affordable adsorbent is feasible to remove MB and CV from wastewater.