Ultrasound-assisted degradation of organic dyes over magnetic CoFe2O4@ZnS core-shell nanocomposite

Abstract

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.

A novel n-type CdS nanorods/p-type LaFeO3 heterojunction nanocomposite with enhanced visible-light photocatalytic performance

“…5,6 However, TiO 2 can absorb only UV light in the solar spectrum, accounting for only 4-5% of sunlight, because of its large energy band gap of 3.2 eV, so that the effective utilization of visible light or solar energy is limited. [7][8][9][10][11][12] To increase the utilization efficiency of sunlight and improve the photocatalytic activity, novel visible-light photocatalysts with high activity and stability must be developed. [13][14][15][16][17][18] Among visible-light-driven photocatalysts, cadmium sulde (CdS), an n-type semiconductor with a band gap of $2.4 eV, is one of the most important semiconductors and has been extensively studied during the past decades.…”

Ultrasonically and Photonically Simulatable Bi‐Ceria Nanocubes for Enhanced Catalytic Degradation of Aqueous Dyes: A Detailed Study on Optimization, Mechanism and Stability

“…Furthermore, the hot spot generated during the ultrasonic cavitation effect in aqueous medium will reach very high temperature of about 1000 °C. Such very high temperature will break down the H 2 O molecules and produces • OH radicals . Hence, produced • OH radicals will also converts TA into HTA.…”

“…These generated • OH radicals and O 2 •− radicals will further degrade the organic dye molecules. In general, these excited electrons by luminescence and generated h + recombine occurs rapidly, leading to insufficient time for catalytic radical generation and the decline in catalytic performance of CeO 2 ,. But in case of 5BCO, the Bi 5d level has pivotal effects on the transformation and generation of excited electrons, with the discomfiture of (e − ‐h +) pair recombination.…”

A novel CoFe2O4@Cr-MIL-101/Y zeolite ternary nanocomposite as a magnetically separable sonocatalyst for efficient sonodegradation of organic dye contaminants from water

“…as the nontoxic products of sonodecomposition reactions (eqn (8)-(16)). 15,18,27,51,52 A comprehensive plausible schematic mechanism of the entire above demonstrated process has been briey depicted in Fig. 11.…”

“…Among them, the sonodecomposition reaction has been exerted as a signicant, effective and environmentally friendly process to eliminate dye contaminants through the formation of cOH (hydroxyl) and cH (proton) radicals and a series of other species like HOOc (perhydroxyl) radicals, O 2 , etc. 14 Furthermore, the versatile sorts of catalysts, including CuFe 2 O 4 /MIL-101/Graphene, 15 TiO 2 /montmorillonite, 16 Yb, B and Ga dopted Er 3+ :Y 3 Al 5 O 12 /TiO 2 , 17 CoFe 2 O 4 @ZnS, 18 Au/NiGa 2 O 4 -Au-Bi 2 O 3 , 19 CoFe 2 O 4 /CdS, 20 InVO 4 /TiO 2 , 21 CeO 2 /TiO 2 , 22 MgO, 23 WO 3 , 24 AgBr, 25 and some others, have been applied to remove dye contaminants through the sonodecomposition activities. In addition to this, metalorganic frameworks (MOFs) are introduced as one of the new kind of organic-inorganic materials.…”