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Hydration accelerator and photocatalyst of nanotitanium dioxide synthesized via surfactant-assisted method in cement mortar
摘要： To develop TiO2-based cement materials, the effect of TiO2 on the cement hydration and photocatalytic reaction should be investigated. The phase, size and shape of TiO2 are important factors for better understanding its application in cement. TiO2 nanoparticles were synthesized by a surfactant-assisted, reverse micelle method to control phase, size and shape by three selected surfactants namely: sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB) and TritonX-100. The synthesized TiO2 nanoparticles were characterized by XRD, SEM and TEM for observation of phase, size and shape. The modified micro structures of admixed cements with the different synthesized TiO2 nanoparticles incorporated were also examined by SEM. Particularly, the hydration process and photocatalytic reaction of the cement mixture were evaluated by heat flow calorimetry and methylene blue (MB) degradation, respectively. Results showed that anatase-rich and smaller size TiO2 nanoparticles provided accelerated cement hydration and the ability to degrade MB photocatalytically at the surface of admixed-TiO2 cement.
关键词： Surfactant-assisted method,Photocatalytic activity,Hydration,Cement,Titanium dioxide nanoparticle
更新于2025-09-23 15:22:29
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Potential use of green TiO2 and recycled membrane in a photocatalytic membrane reactor for oil refinery wastewater polishing
摘要： Membrane bioreactors (MBRs) have been successfully used in oil refinery wastewater treatments. However, a polishing treatment of the MBR permeate is required to remove the recalcitrant organic compounds. In this study, the coupling of a photocatalytic membrane reactor (PMR) and MBR was investigated for the treatment of oil refinery wastewater. Titanium dioxide (TiO2) nanoparticles, synthesised by a cleaner route assisted by microwave radiation, and recycled membrane, an end-of-life reverse osmosis membrane converted to an ultrafiltration membrane by oxidation, were prepared for use as a PMR. The recycled membrane could completely retain the catalyst particles. The PMR exhibited higher efficiency and stability in the removal of organic matter than those of the individual photocatalysis and membrane processes. Adsorption of organic compounds was observed on the catalyst surface. These compounds were degraded releasing active sites for reaction/adsorption. A chemical oxygen demand analysis revealed that up to 60% of the organic matter in the MBR permeate was decomposed in the PMR, which also contributed to membrane fouling mitigation. The membrane fouling resistance in the PMR was 7.3 times lower than that in the system operated without the catalyst. In addition, membrane degradation was not observed upon the use of the catalyst. The results indicate that the PMR with the green TiO2 and recycled membrane is a highly active, stable, and promising system for the polishing of oil refinery wastewater previously treated by the MBR.
关键词： oil refinery wastewater,titanium dioxide nanoparticle,recycled membrane,photocatalytic membrane reactor,recalcitrant compound
更新于2025-09-19 17:13:59
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MODIFIED ABSORPTION FEATURES OF TITANIA-ERBIUM INCORPORATED PLASMONIC TELLURITE GLASS SYSTEM
摘要： Achieving efficient lasing glass materials with enhanced absorption and emission cross-section by reducing the Rare Earth (RE) concentration quenching is a challenging issue. Metal nanoparticles (NPs) together with RE ions in the glass matrix are thought as a suitable alternative to overcome the limitations of concentration quenching and weak absorption of inorganic glasses. We prepare a series of Titania-Erbium doped Tellurite glass system with the form (69-x)TeO2-20ZnO-10Na2O-1Er2O3-(x)TiO2, where 0 ≤ x≤ 1.0 mol% via melt-quenching method with optimum erbium contents and varying TiO2 NPs concentrations. The NPs concentration dependent modifications in the absorption characteristics are scrutinized. Glasses are characterized via UV-Vis-NIR and XRD measurements. XRD pattern verifies the amorphous nature of prepared samples. The incorporation of TiO2 NPs is demonstrated to enhance the absorption intensity significantly. This augmentation is attributed to the effect of Surface Plasmon Resonance (SPR) mediated strong local electric field that is swallowed by neighboring Er3+ ions. The observed modification in optical energy band gap and Urbach energy are ascribed to the strong electric field around NPs that interact with the ligand of glass network to transform weak bond into defects. This observation is useful for the development of plasmonic nanoglass materials applicable for photonic devices.
关键词： absorption spectra,Tellurite glass,titanium dioxide nanoparticle
更新于2025-09-19 17:13:59