Photogeneration of reactive oxygen species over ultrafine TiO2 particles functionalized with rutin–ligand induced sensitization and crystallization effects
Abstract:Interaction of amorphous and crystalline TiO 2 ultrafine particles (2-6 nm) with rutin results in the formation of colored nanomaterials of an excellent dispersity and enhanced colloidal stability in aqueous media. The FTIR and Raman spectra confirmed attachment of the rutin ligand via vicinal hydroxyl groups in a catechol-like fashion. The binding of rutin to amorphous TiO 2 gives rise to spontaneous crystallization of the parent nanoparticles into hydrogen titanates (H 2 Ti 3 O 7 and H 2 Ti 12 O 25). Such st… Show more
“…Hole (h+) and electron (e−) are symbols for the holes and electrons, respectively, in the processes listed in Table 2. Many other types of reactive oxygen species are generated during this process, including hydroxyl radicals (OH*), super-oxide radicals (O 2 ), and hydrogen peroxide (H 2 O 2 ) [22]. Of several reactive oxygen species that can be generated through photocatalytic oxidation processes, OH* radicals have the highest chemical reactivity and lowest selectivity.…”
Section: Photocatalytic Reduction Of Vocsmentioning
The photocatalytic oxidation (PCO) process is one of the most preferred, inexpensive, and environmentally friendly methods for VOC removal. It has been determined that this method can remove a wide range of organic pollutants. The removal of benzene and toluene pollutants, two important VOCs commonly encountered in flue gases, has been studied in the scope of this study using the photocatalytic oxidation method under UVA irradiation. For this purpose, the photocatalytic activity of the photocatalyst increased by the metal/metal doping process. Two different metals, a noble metal (Ag) and a transition metal (Ni), were used together for the doping of TiO2 nanoparticles, and the photocatalysts attached to a glass surface were prepared. Four different doping percentages were used for photocatalysts: 0.5%, 1%, 2.5%, and 5%. Several PCO experiments were conducted under different temperatures (120, 150, and 180 °C) and humidity conditions (25 and 50%). Photocatalytic oxidation experiments were carried out with artificially produced benzene and toluene gases, and the success of the system was evaluated with respect to removal efficiency calculations. The UVA light source was used for the photocatalytic experiments. The results of the study indicated that the removal efficiencies of toluene were found to be higher than those of benzene, and the most suitable conditions were determined to be 50% humidity and a 120 °C environment with the use of a 1% doped photocatalyst.
“…Hole (h+) and electron (e−) are symbols for the holes and electrons, respectively, in the processes listed in Table 2. Many other types of reactive oxygen species are generated during this process, including hydroxyl radicals (OH*), super-oxide radicals (O 2 ), and hydrogen peroxide (H 2 O 2 ) [22]. Of several reactive oxygen species that can be generated through photocatalytic oxidation processes, OH* radicals have the highest chemical reactivity and lowest selectivity.…”
Section: Photocatalytic Reduction Of Vocsmentioning
The photocatalytic oxidation (PCO) process is one of the most preferred, inexpensive, and environmentally friendly methods for VOC removal. It has been determined that this method can remove a wide range of organic pollutants. The removal of benzene and toluene pollutants, two important VOCs commonly encountered in flue gases, has been studied in the scope of this study using the photocatalytic oxidation method under UVA irradiation. For this purpose, the photocatalytic activity of the photocatalyst increased by the metal/metal doping process. Two different metals, a noble metal (Ag) and a transition metal (Ni), were used together for the doping of TiO2 nanoparticles, and the photocatalysts attached to a glass surface were prepared. Four different doping percentages were used for photocatalysts: 0.5%, 1%, 2.5%, and 5%. Several PCO experiments were conducted under different temperatures (120, 150, and 180 °C) and humidity conditions (25 and 50%). Photocatalytic oxidation experiments were carried out with artificially produced benzene and toluene gases, and the success of the system was evaluated with respect to removal efficiency calculations. The UVA light source was used for the photocatalytic experiments. The results of the study indicated that the removal efficiencies of toluene were found to be higher than those of benzene, and the most suitable conditions were determined to be 50% humidity and a 120 °C environment with the use of a 1% doped photocatalyst.
Oil and gas wastewater refers to the waste stream produced in special production activities such as drilling and fracturing. This kind of wastewater has the following characteristics: high salinity, high chromaticity, toxic and harmful substances, poor biodegradability, and a difficulty to treat. Interestingly, nanomaterials show great potential in water treatment technology because of their small size, large surface area, and high surface energy. When nanotechnology is combined with membrane treatment materials, nanofiber membranes with a controllable pore size and high porosity can be prepared, which provides more possibilities for oil–water separation. In this review, the important applications of nanomaterials in wastewater treatment, including membrane separation technology and photocatalysis technology, are summarized. Membrane separation technology is mainly manifested in ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO). It also focuses on the application of semiconductor photocatalysis technology induced by TiO2 in the degradation of oil and gas wastewater. Finally, the development trends of nanomaterials in oil and gas wastewater treatment are prospected.
“…ZnO nanoparticles are effective on fungi like Fusarium as antimicrobial agents [12]. Complexation of TiO 2 particles with rutin shifts the photogeneration of hydroperoxyl (HOO) and hydroxyl (HO) radicals toward visible light (lambda > 400 nm) [13]. As the green tuff contains small amounts of similar components, the elemental distribution is measured and investigated especially for TiO 2 existence on zeolite.…”
Hinai green tuff, which is found in Akita Prefecture, Japan, is used for the production of building materials, etc. About 60% of all stone is emitted as waste powder and therefore it is important to find ways for recycling it. In this work, the characteristics of green tuff powder have been investigated. The results of scanning electron microscope (SEM) and elemental map observations indicate that the green tuff contains TiO2 on zeolite. The green tuff can therefore be used as a natural catalyst for producing hydrogen peroxide with moisture and oxygen with light. The optimum calcined temperature of the green tuff powder is about 800 °C, producing the hydroxyl radical from hydrogen peroxide decomposition without ultraviolet light (UV) and decomposition of the superoxide anion. As the application of green tuff powder, Cavendish banana trees found in the Philippines infected by a new Panama disease were treated with powder suspension in order to remove the fungus (a type of Fusarium wilt) due to the photocatalyst characteristics of powder. The suspension, prepared by using the powder was sprayed on the infected banana trees for about one month. Photograph observation indicated that the so-called 800 °C suspension spray was more effective in growing the infected banana trees.
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