Undoped CeO2 and 0.50-5.00 mol% Fe-doped CeO2 nanoparticles were prepared by a homogeneous precipitation combined with homogeneous/impreganation method, and applied as photocatalyst films prepared by a doctor blade technique. The superior photocatalytic performances of the Fe-doped CeO2 films, compared with undoped CeO2 films, was ascribed mainly to a decrease in band gap energy and an increase in specific surface area of the material. The presence of Fe(3+) as found from XPS analysis, may act as electron acceptor and/or hole donor, facilitating longer lived charge carrier separation in Fe-doped CeO2 films as confirmed by photoluminescence spectroscopy. The 1.50 mol% Fe-doped CeO2 film was found to be the optimal iron doping concentration for MO degradation in this study.

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Photocatalytic Degradation of Methyl Orange by CeO2 and Fe–doped CeO2 Films under Visible Light Irradiation

A simple and cost-effective one-step hydrothermal method, which was based on the reactions of tin(IV) chloride pentahydrate and different dosages of thioacetamide in water at 190 °C for 6 h, was employed for the synthesis of composition-tunable SnS 2 /SnO 2 nanoheterojunctions (e.g., SnS 2 /SnO 2 -A, SnS 2 /SnO 2 -B and SnS 2 /SnO 2 -C). The photocatalytic properties of the as-synthesized SnS 2 /SnO 2 nanoheterojunctions were tested by the reduction of aqueous Cr(VI) under visible-light ( λ  > 420 nm) irradiation. Furthermore, the photocatalytic efficiency of SnS 2 /SnO 2 -B was compared with those of PM-SnS 2 /SnO 2 (which denotes the physically mixed SnS 2 /SnO 2 nanocomposite with the same composition as SnS 2 /SnO 2 -B) and SnS 2 nanoflakes at different dosages of photocatalysts. It was observed that (i) the photocatalytic activities of the as-synthesized SnS 2 /SnO 2 nanoheterojunctions depended on their compositions, and SnS 2 /SnO 2 -B with 70 mol% SnS 2 displayed the highest photocatalytic activity; (ii) SnS 2 /SnO 2 -B invariably exhibited higher photocatalytic efficiencies than PM-SnS 2 /SnO 2 and SnS 2 nanoflakes at different dosages of photocatalysts; (iii) the washing with 1 mol/L HNO 3 can effectively regenerate the used photocatalyst; (iv) SnS 2 /SnO 2 -B exhibited good photocatalytic stability in reuses, with regeneration by 1 mol/L HNO 3 -washing after each cycle of photocatalytic use; and (v) Cr(VI) was reduced to Cr(III). The possible formation mechanism of SnS 2 /SnO 2 nanoheterojunctions and the reasons accounting for the photocatalytic results were also discussed.

One-step hydrothermal synthesis of high-performance visible-light-driven SnS2/SnO2 nanoheterojunction photocatalyst for the reduction of aqueous Cr(VI)

Photocatalytic reduction of Cr(VI) over different TiO2 photocatalysts and the effects of dissolved organic species

SnS 2 /TiO 2 nanocomposites with adjustable TiO 2 contents were synthesized directly via the solvothermal reactions of SnCl 4 ·5H 2 O, thioacetamide and different amounts of tetrabutyl titanate in the mixed solvents of ethanol and acetic acid at 180 °C for 12 h. The structures, compositions, Brunauer–Emmett–Teller (BET) specific surface areas and optical properties of the as-synthesized products were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, N 2 adsorption and UV–vis diffuse reflectance spectra, and their photocatalytic properties were tested for the reduction of aqueous Cr(VI) under visible light ( λ  > 420 nm) irradiation. Furthermore, contrast photocatalytic experiments were also conducted for different doses of the as-synthesized SnS 2 /TiO 2 nanocomposite, SnS 2 and physical mixture of SnS 2 and TiO 2 . It was found that the as-synthesized SnS 2 /TiO 2 nanocomposite with a suitable TiO 2 content (e.g., 44.5 mass% TiO 2 ) not only exhibited extraordinary superior photocatalytic activity to SnS 2 , TiO 2 and physical mixture of SnS 2 and TiO 2 (44.5 mass%) at different catalyst doses, but also had good photocatalytic stability. Moreover, Cr(VI) can be reduced to Cr(III) by SnS 2 /TiO 2 -mediated photocatalysis. The tight heterojunction structure of the as-synthesized SnS 2 /TiO 2 nanocomposite, which can facilitate interfacial electron transfer and reduce the separation and self-agglomeration of two components, was considered to play an important role in achieving its greatly improved photocatalytic performance.

One-step in situ solvothermal synthesis of SnS2/TiO2 nanocomposites with high performance in visible light-driven photocatalytic reduction of aqueous Cr(VI)

Titanium oxide based photocatalytic materials development and their role of in the air pollutants degradation: Overview and forecast.

Lifetime and regeneration of immobilized titania for photocatalytic removal of aqueous hexavalent chromium.

Determination of biodegradable dissolved organic carbon using entrapped mixed microbial cells

The transformation of waste Bakelite to replace natural fine aggregate in cement mortar

Study of mechanical properties and recommendations for the application of waste Bakelite aggregate concrete

Bakelite is prohibited to dispose for direct land filling and open burning because of the unsafe disposal and emission reasons. The purposes of this research are characterization of BPW and using BPW as aggregates in concrete products. The physical characteristics of BPW, the bulk specific gravity was 1.30-1.40 g/cm. Chemical composition of BPW, total carbon, hydrogen, oxygen and sulfur was 53.4, 4.0, 11.6 and 0.017%, respectively. Composition of ash of Bakelite, CaO, SiO2 and SO3 was 94.53, 5.14 and 0.33%, respectively. pH value of BPW and fine Bakelite plastics waste (FBPW) was 8.10 and 12.00, respectively. Water absorption capacity of BPW and FBPW was 0% and 25%, respectively. After grinding, BPW become FBPW. The water absorption of FBPW was 25%. Using BPW as aggregates in concrete products by preparing and testing mortar samples with 0%, 20%, 40%, 80% and 100% replacement percentage at each curing age 7, 14 and 28 days. Based on a testing standard of American Society for Testing Material (ASTM). The specimen test results showed that the compressive strength and density of Bakelite plastics waste Mortar (BPWM) was lower than Conventional Mortar (CM). The compressive strength decreased with increasing of replacement percentage and it increased with curing time. 

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Seree Tuprakay

Papers

Lifetime and regeneration of immobilized titania for photocatalytic removal of aqueous hexavalent chromium.

Determination of biodegradable dissolved organic carbon using entrapped mixed microbial cells

The transformation of waste Bakelite to replace natural fine aggregate in cement mortar

Study of mechanical properties and recommendations for the application of waste Bakelite aggregate concrete

A Study Bakelite Plastics Waste from Industrial Process in Concrete Products as Aggregate