Search

In this study, nanocrystalline ZnNdxFe2−xO4 ferrites with x = 0.0, 0.01, 0.03 and 0.05 were fabricated and used as a catalyst for dye removal potential. The effect of Nd3+ ions substitution on the structural, optical and photo-Fenton activity of ZnNdxFe2−xO4 has been investigated. The addition of Nd3+ ions caused a decrease in the grain size of ferrites, the reduction of the optical bandgap energies and thus could be well exploited for the catalytic study. The photocatalytic activity of the ferrite samples was evaluated by the degradation of Rhodamine B (RhB) in the presence of H2O2 under visible light radiation. The results indicated that the ZnNdxFe2−xO4 samples exhibited higher removal efficiencies than the pure ZnFe2O4 ferrites. The highest degradation efficiency was 98.00%, attained after 210 min using the ZnNd0.03Fe1.97O4 sample. The enhanced photocatalytic activity of the ZnFe2O4 doped with Nd3+ is explained due to the efficient separation mechanism of photoinduced electron and holes. The effect of various factors (H2O2 oxidant concentration and catalyst loading) on the degradation of RhB dye was clarified.

The synthetic textile effluents often contain a large amount of pretreated dyes, which possibly offers the high degree of toxicity, causing many negative influences on the human health and environment. In this work, we reported the fabrication of ZnFe2O4@ZnO nanocomposite by the facile solution combustion and investigated their potential for the photocatalytic removal of Rhodamine B under the visible light LED lamps. The materials were characterized by XRD, DRS, EDX, TEM, and N 2 adsorption desorption isotherm measurements. The results exhibited the highest Rhodamine B degradation efficiency of 91.87% using ZnFe2O4-50%@ZnO at the concentration of 5.0 mg L−1 and catalyst dosage of 0.75 g L−1. Possible photocatalytic mechanisms were proposed with the main role of reactive oxygen species ( ⋅ O 2 – , ⋅ OH) over the electron excitation using the visible light source. The ZnFe 2O4-50%@ZnO catalyst could reuse at least four cycles. Through a comparative study, ZnFe 2O4-50%@ZnO exhibited the better photocatalytic performance than other nanocomposites. It may be, therefore, expected as a promising photocatalyst for the treatment of organic dyes.

Lanthanum (La)-doped zinc oxide nanoparticles were synthesized with different La concentrations by employing a gel combustion method using poly(vinyl alcohol) (PVA). The as-synthesized photocatalysts were characterized using various techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), photoluminescence (PL) spectroscopy, and UV&ndash, visible absorption spectroscopy. The average size of ZnO nanoparticles decreased from 34.3 to 10.3 nm with increasing concentrations of La, and the band gap, as evaluated by linear fitting, decreased from 3.10 to 2.78 eV. Additionally, it was found that the photocatalytic activity of doped samples, as investigated by using methyl orange dye under visible lights, improved in response to the increase in La concentration. The decomposition of methyl orange reached 85.86% after 150 min in visible light using La0.1Zn0.9O as the photocatalyst.