Preparation, characterization, and adsorption studies of core@shell SiO$_{2}$@CeO$_{2}$ nanoparticles: a new candidate to remove Hg(II) from aqueous solutions

Abstract

SiO 2 supported core@shell nanoparticles (CSNs) have recently attracted great attention due to their unique, tunable, optical, photocatalytic, and higher adsorption properties. In this study, SiO 2 @CeO 2 CSNs were synthesized using a chemical precipitation technique and characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) analysis. XRD analysis showed that SiO 2 particles were the core while CeO 2 particles were the shell. It was seen as a new band at 961 cm −1 of the oxygen bridge between Si and Ce atoms from FT-IR results; SiO 2 and CSNs were spherical (0.5-0.6 µ m) from SEM and TEM analyses. Different parameters such as contact time, initial concentration, pH, and temperature were investigated. The optimum conditions for temperature, pH, and contact time were 25 • C, 8.0, and 60 min, respectively. In addition, the equilibrium adsorption data were interpreted using Langmuir and Freundlich models to describe the uptake of Hg(II). The Freundlich isotherm model (R 2 : 0.99) fit better than Langmuir and the qmax value was 153.8 µ g g −1 at various concentrations (0.1-1 mg L −1). The thermodynamic parameters were also calculated and, from these results, it can be shown that our synthesized particles can be used in water purification systems to remove Hg(II).

Enhanced NH3 gas-sensing performance of silica modified CeO2 nanostructure based sensors

“…The peaks at 980 cm -1 and 854 cm -1 correspond to the asymmetric stretching vibration and symmetric stretching of Si-O-Si [35]. Moreover, the peak observed at 936 cm -1 should be due to the stretching vibration band of Ce-O-Si bonds [37], which reveals that Si 4+ is integrated into the surface of CeO2.…”

Synthesis of Ce/SiO2 Composited Cross‐Linked Chitosan Flocculation Material and Its Application in Decolorization of Tartrazine Dye

“…The XRD patterns of SiO 2 , C‐CTS, CTS‐S and C‐CTS‐S are presented in Figure . As shown in Figure , the broad peak is observed at about 22.31 ο belonging to the amorphous SiO 2 . The strong and broad bread peak at 10–30 ο of CTS‐S has a shift to a low angle (15.85 ο ) compared to pure SiO 2 , this could be attributed that the composite of SiO 2 and cross‐linked CTS leads to the lattice distortion of SiO 2 and significantly influences the crystal structure of the obtained products.…”

“…For the samples labeled C‐CTS‐S and C‐CTS, the amorphous phase can be identified by the fact that there are no sharp, single, intense and well recognizable peaks but only unclearly, low‐intense and broad recognizable peaks, it is the evidence of the disorder structure of the products containing Ce, which is demonstrated by SEM. The individual phases of Ce 2 O 3 and CeO 2 are not observed in C‐CTS and C–CTC−S, but there have appeared a peak at 26.68 ο in CTS‐S and C–CTC−S, which may be a new phase of Si species. The broad peak occurred at 20.54 ο in C‐CTS (see attached chart) resulted from the neat arrangement and crystallization of part of CTS molecular, and this peak is covered up by diffraction peak of SiO 2 in CTS‐S and shifts to 19.66 ο in C–CTC−S, which indicates that SiO 2 species not only stayed on the surface of CTS but entered its chain layer structure during the composite process.…”

“…In recent years, a great effort has been made to dispose dye wastewater contamination. Treatment methods such as coagulation/flocculation, advanced oxidation, adsorption, catalytic degradation, micro‐electrolysis and biological methods have been continuously exploring for decade years. Among these methods, flocculation, as one of the most practiced technologies, has been wildly attracted attention by researchers because of its simple operation and design, low cost and high efficiency .…”

Removal of heavy metals (Cd and Pb) from aqueous solutions by adsorption using synthetic tobermorite prepared from bio-municipal wastes as adsorbent

“…The decrease in the adsorption of adsorbate observed as the concentration (mg/L) increases might be attributed to the reduction of vacant sites on the adsorbents as they are completely filled with ions of adsorbate (Pb 2+ and Cd 2+ ). This indicates that uptake or efficiency of the adsorption process does not depend solely on adsorbent properties, but also on the initial adsorbate concentration (mg/L) in solution [12,29]. However, TbVI exhibited better uptake efficiency in Pb removal as the concentration of the adsorbate increases.…”