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Solution combustion synthesis of ZnO powders using various surfactants as fuel
摘要： Single phase ZnO powders were synthesized by solution combustion method using various surfactants as fuel. The effects of hydrocarbon tail length on the combustion behavior, phase evolution, morphology, optical properties, and photocatalytic activity were studied by thermal analysis, X-ray diffraction, electron microscopy, and photoluminescence spectroscopy techniques. The specific surface area and pore volume increased with the addition of citric acid as auxiliary fuel due to the increase of released gaseous products. ZnO powders obtained by mixed fuels show higher crystallinity and specific surface area, leading to the higher photodegradation of methylene blue under ultraviolet irradiation. Moreover, the photocatalytic activity increased in the presence of ZnO powders prepared by the longest hydrocarbon tail.
关键词： ZnO,Surfactant,Photocatalytic activity,Porous materials
更新于2025-09-04 15:30:14
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A liquid crystal based method for detection of urease activity and heavy metal ions by using stimulus-responsive surfactant-encapsulated phosphotungstate clusters
摘要： A liquid crystal (LC) based method is described for the sensitive determination of the activity of urease and of heavy metal ions which acts as inhibitors. Stimulus-responsive surfactant-encapsulated phosphotungstate clusters (SECs) were fabricated and deposited onto octadecyltrichlorosilane-coated glass. A copper TEM grid filled with LCs was placed on the substrate to construct the LC optical cell. Upon addition of water to the LC interface, the optical appearance of LCs on the glass undergoes a bright-to-dark shift due to an orientational transition of the LCs from a planar to a homeotropic state. However, the LCs display a bright appearance if they are pretreated with an aqueous solution containing urea and urease. This is caused by the disassemby of the SECs from the glass surface due to an increase of the pH value that is induced by the enzymatic hydrolysis of urea by urease. The method is highly sensitive and can detect urease activities as low as 0.03 mU/mL. It can also be applied to the determination of heavy metal ions which exert an inhibitory effect on the activity of urease. For example, Cu(II) can be quantified via urease inhibition in 1 nM concentration.
关键词： Ionic liquid,Stimulus-responsive material,Surfactant,Sensor layer,Polyoxometalates,Urease,Nanocomposites,Ionic self-assembly,Liquid crystal
更新于2025-09-04 15:30:14
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Improvement of photocatalyst properties of magnetic NPs by new anionic surfactant
摘要： In this research, Fe3O4 NPs was synthesized by co- precipitation approach. Then SiO2 shell was grown on the Fe3O4 core. Synthesized NPs were characterized by means of XRD, FTIR, VSM, TGA, SEM and TEM. The magnetic properties of core and core-shell NPs was 74 and 42 emu/g, respectively. The TEM picture of core-shell was showed thickness shell of SiO2 on the Fe3O4 NPs. The size of this shell about 2.5nmWhich caused the core magnetic property to be well preserved. Photocatalyst activity of the synthesized NPs was investigated by using methyl orange (MO) and methylene blue (MB) as pollutant at different pH. For first time sodium citrate was used to improvement photo- degradation. The Fe3O4 indicated good photocatalyst activity for photo-degradation and it’s activity was considerably increased after SiO2 shell growth.
关键词： Fe3O4@SiO2,Photocatalyst,Tri sodium citrate,Fe3O4,Anionic surfactant
更新于2025-09-04 15:30:14