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A novel n–p CdS nanorods/LaFeO3 (CdS NRs/LFO) heterojunction nanocomposite was prepared via a solvothermal route and applied as a visible-light photocatalyst for enhanced degradation of organic dye pollutants.

The sonocatalytic activity of the magnetic CuS/CoFeO (CuS/CFO) nanohybrid was studied through the HO-assisted system for degradation of water soluble organic pollutants such as methylene blue (MB), rhodamine B (RhB) and methyl orange (MO). The CuS/CFO nanohybrid was fabricated at 200 °C by hydrothermal method. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray microanalysis (EDX), Fourier-transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, magnetic measurements, and Brunauere-Emmette-Teller (BET) were employed for the characterizing the structure and morphology of the so-synthesized nanohybrid. Compared with sonolysis/HO, the higher degradation of MB (25 mg/L) was achieved via sonocatalytic process. The degradation efficiency of sonolysis/HO, sonocatalysis using CuS/HO, CFO/HO and CuS/CFO/HO systems was 6%, 62%, 23% and 100% within reaction time of 30 min for MB, respectively. The integration of HO and catalyst dosage intensified the sonocatalytic degradation of MB. On the other hand, adding a hydroxyl radical (OH) scavenger (tert-butyl alcohol) and a hole scavenger (disodium ethylenediaminetetraacetate) decreased the degradation efficiency from 100% to 35% and 72% within 30 min, indicating the OH radicals as prominent oxidizing agent of this process. Furthermore, the magnetic property of the sample helped for easier separation of the nanohybrid, made it recyclable with a negligible decline in the performance even after four consecutive runs.

Magnetic CoFeO@ZnS core-shell nanocomposite was successfully synthesized via one-step hydrothermal decomposition of zinc(II) diethanoldithiocarbamate complex over CoFeO nanoparticles at low temperature of 200°C. The obtained nanocomposite was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, UV-Vis spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, magnetic measurements, and Brunauere-Emmette-Teller. The results confirmed the formation of CoFeO@ZnS nanocomposite with the average crystallite size of 18nm. The band gap of 3.4eV was obtained using UV-vis absorption of CoFeO@ZnS nanocomposite, which made it a suitable candidate for sono-/photo catalytic processes. This nanocomposite was applied as a novel sonocatalyst for the degradation of organic pollutants under ultrasound irradiation. The results showed complete degradation of methylene blue (MB) (25mg/L) within 70min in the presence of CoFeO@ZnS nanocomposite and HO (4mM). The trapping experiments indicated that OH radicals are the main active species in dye degradation. In addition, sonocatalytic activity of the CoFeO@ZnS nanocomposite was higher than those of pure ZnS and CoFeO, showing that the combining ZnS with magnetic CoFeO could be an excellent choice to improve its sonocatalytic activity. The nanocomposite could be magnetically separated and reused without any observable change in its structure and performance even after five consecutive runs.