Cerium–Bismuth Oxides/Oxynitrates with Low Toxicity for the Removal and Degradation of Organophosphates and Bisphenols

Abstract

Nanoscale cerium–bismuth oxides/oxynitrates were prepared by a scalable low-temperature method at ambient pressure using water as the sole solvent. Solid solutions were formed up to a 1:1 Ce/Bi molar ratio, while at higher doping levels, bismuth oxynitrate photocatalysts with a pronounced layered structure were formed. Bismuth caused significant changes in the structure and surface properties of nanoceria, such as the formation of defects, oxygen-containing surface groups, and Lewis and Brønsted acid sites. The prepared bifunctional adsorbents/photocatalysts were efficient in the removal of toxic organophosphate (methyl paraoxon) from water by reactive adsorption followed by photocatalytic decomposition of the parent compound and its degradation product (p-nitrophenol). Bi-doped ceria also effectively adsorbed and photodegraded the endocrine disruptors bisphenols A and S and outperformed pure ceria and the P25 photocatalyst in terms of efficiency, durability, and long-term stability. The very low toxicity of Bi-nanoceria to mammalian cells, aquatic organisms, and bacteria has been demonstrated by comprehensive in vivo/in vitro testing, which, in addition to its simple “green” synthesis, high activity, and durability, makes Bi-doped ceria promising for safe use in abatement of toxic chemicals.

Metal–Organic Framework-Derived Hierarchical Ag/Sr6Bi2O9-α-Bi2O3 Ternary Photocatalyst for Micropollutant Remediation and Bacterial Photoinactivation

“…In the Bi 4f highresolution spectra, pure BO exhibits a doublet at 159.1 and 164.4 eV, which correspond to the binding energy (BE) of 4f 7/2 and 4f 5/2 microstates of Bi 3+ ions in oxide coordination (Figure 5b). 46 The spectral doublet of Bi 3+ ions in SBO appears at 158.9 and 164.2 eV. The Ag/SBO-BO displayed Bi 3+ spectra at 158.8 and 164.1 eV.…”

“…The full-scan spectra revealed the occurrence of required elements, i.e., Bi, Sr, O, and Ag along with adventitious carbon in the prepared samples (Figure a). In the Bi 4f high-resolution spectra, pure BO exhibits a doublet at 159.1 and 164.4 eV, which correspond to the binding energy (BE) of 4f 7/2 and 4f 5/2 microstates of Bi 3+ ions in oxide coordination (Figure b) . The spectral doublet of Bi 3+ ions in SBO appears at 158.9 and 164.2 eV.…”

“…The O 1s spectrum of SBO has been deconvoluted into two peaks positioned at 530.1 and 531.8 eV that correspond to lattice oxides and surface-adsorbed water, respectively (Figure d). The BO material also exhibited a dominant peak at 530.3 eV together with a less intense broad feature at 532.0 eV. , The former peak is assigned to the lattice oxides of monoclinic Bi 2 O 3 , whereas the 532.0 eV peak occurs due to the presence of adsorbed water. The Ag/SBO-BO composites on the other hand show a distinct spectral feature, which is deconvoluted into three peaks.…”

“…The BO material also exhibited a dominant peak at 530.3 eV together with a less intense broad feature at 532.0 eV. 46,47 The former peak is assigned to the lattice oxides of monoclinic Bi 2 O 3 , whereas the 532.0 eV peak occurs due to the presence of adsorbed water. The Ag/SBO-BO composites on the other hand show a distinct spectral feature, which is deconvoluted into three peaks.…”

Modulating Ce3+ Sites in Ce‐Zr Oxide Nanocatalysts through Protamine Biomineralization for Organophosphate Dephosphorylation

“…Ceria can exist in dual oxidation states as Ce 3+ and Ce 4+ , enabling the ability to accommodate a high density of oxygen vacancies (Vo), which enhances the catalytic activity for OPD due to the cooperative redox property of Ce 3+ and Ce 4+ [1,6,9,11] . The addition of metal dopants to ceria has shown to improve Vo concentration and associated catalytic activity for the decomposition of OPs [1,12–15] …”