Sonochemical synthesis of highly efficient Ag3PO4-Guar gum nanocomposite with photo-oxidation property under visible light irradiation

Balachandramohan, Jayachandrabal; Singh, Randeep; Sivasankar, Thirugnanasambandam; Manickam, Sivakumar

doi:10.1016/j.cep.2021.108549

Cited by 4 publications

(2 citation statements)

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“…In general, the following features of changes on the RbTe1.5W0.5O6 complex oxide surface after catalysis of methyl methacrylate polymerization should be distinguished. From the previous study of the surface and the photocatalytic properties of RbTe1.5W0.5O6, it is known that the compound's surface is enriched with Rb atoms, due to their migration from the volume to the surface through the channels of the crystal lattice [32]. It leads to the appearance of a small positive charge on the surface of the powder particles, which in an aqueous solution well adsorbs water and OH -.…”

Section: Resultsmentioning

confidence: 99%

“…Such studies have been carried out for many catalysts with a practical focus of research. For example, the reuse of catalysts Ag3PO4-Guar gum [32], Fe3O4/CeO2/g-C3N4 [33], SiO2/WO3-TiO2@rGO [34] is possible for several cycles with a slight loss of activity after solvent treatment and heating. Thus, the study of the reuse possibility of the complex oxide RbTe1.5W0.5O6 is relevant due to photocatalytic activity for polymerization processes.…”

Section: Introductionmentioning

confidence: 99%

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The effect of methyl methacrylate transformations during photocatalysis in the presence of RbTe1.5W0.5O6 on the change of the complex oxide surface

Chasova

Fukina

Boryakov

et al. 2022

Izvestiâ vuzov. Prikladnaâ himiâ i biotehnologiâ

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The features of the surface changes of the RbTe1.5W0.5O6 photocatalyst during polymerization processes involving methyl methacrylate (MMA) under irradiation with visible light λ= 400–700 nm at a temperature of 20–25 °C, as well as regeneration conditions for its reuse, have been studied. The realization of a chemical reaction in a mixture of a photocatalyst and a monomer is determined by its kinetic parameters and the concentration of reacting particles. The formation of OH• radicals, which are active in radical polymerization, occurs in this case by both ways: interacting between water molecules adsorbed on the surface, as well as during the recovery of oxygen dissolved in water. Due to the high reactivity of the hydroxyl radical, an active process of radical polymerization of MMA could be expected. However, the formation of polymethyl methacrylate (PMMA) in the reaction takes place with a low conversion – the formation of 5–10% polymer, which is related to changes on the surface of the complex oxide RbTe1.5W0.5O6 during the reaction. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) methods have been used to investigate the catalyst surface. The presence of organic and polymer substrates was revealed on the catalyst surface after the reaction. As a result of the catalyst treatment by ultrasound in an aqueous emulsion, polymer macromolecules are not identified on the surface, but chemically adsorbed monomer and oligomers formed under the ultrasound destruction of the polymer are presented. Other methods of cleaning the catalyst surface by washing in different solutions as chloroform and tetrahydrofuran also are not effective and cause the adsorbates transformations on the surface. It leads to decreasing the RbTe1.5W0.5O6 catalyst's activity for repeated polymerization. Thus, to successful regeneration of the catalyst's powder not only ultrasound treatment is required, but also heating it at 300–400 °C to remove organic substrates.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%