Ti-containing mesoporous silica for methylene blue photodegradation (original) (raw)
Related papers
Synthesis and Characterization of SiO2/TiO2 as Photocatalyst on Methylene Blue Degradation
Catalysts
The paper presents a modification of titanium dioxide with fumed silica. The SiO2/TiO2 photocatalysts were obtained by the sol-gel method and then were calcined under an argon atmosphere. Various SiO2 weights (2–17.2 wt.%) were used in the materials’ preparation stage. The obtained samples were characterized using advanced analytical methods, such as FT-IR/DRS infrared spectroscopy, X-ray diffraction, SEM scanning electron microscopy, and UV-Vis/DRS spectroscopy. The BET specific surface area and zeta potential of samples were also measured. Based on the obtained results, it was observed that the modification of titanium dioxide with SiO2 effectively inhibited the increase in crystallite size of anatase and brookite during calcination and the decrease in specific surface area values. Moreover, the presence of SiO2 in the nanomaterials contributed to the increase in the size of specific surface area and the change in band gap energy values. The photocatalytic activity was determined ...
Photocatalytic Activity of TiO2-containing Al-Mesoporous Silica Thin Films
Journal of Oleo Science, 2006
The photocatalytic activity of TiO 2 coated on Al-modified folded mesoporous silica thin films (Al-MSF), TiO 2 /Al-MSF and Ti-, Al-MSF, has been investigated by monitoring the decomposition of methylene blue (MB). The TiO 2 /Al-MSF and Ti-, Al-MSF were prepared on substrates by two independent procedures, i.e., ion-exchange and sol-gel. The Ti-, Al-MSF was found to exhibit higher reactivity than TiO 2 /Al-MSF, while both films showed higher performance than conventional powdered TiO 2. A detailed analysis of the origin of the photocatalytic reactivity for these TiO 2 coated Al-modified mesoporous silica thin films toward the decomposition of MB is presented here.
Catalysts, 2022
The titanium dioxide-silicon dioxide (TiO2-SiO2) nanocomposite used for the study was synthesized using a sol-gel method followed by UV-treatment. The physicochemical properties of the synthesized catalyst, TiO2-SiO2 were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL). The photocatalytic degradation of methylene blue (MB) dye was evaluated in the presence of TiO2-SiO2 and reactive chlorine species (RCS) under experimental conditions. By comparing the important reaction processes in the study, including photocatalysis, chlorination and photocatalytic chlorination, it was found out that the process of photocatalytic chlorination had the highest photodegradation efficiency (95% at 60 min) of the MB under optimum reaction conditions (MB = 6 mg L−1, catalyst = 0.1 g and pH = 4). The enhanced removal of MB from the aqueous medium was identified because of...
Characterization and evaluation of the photocatalytic properties of wormhole-like mesoporous silica
Abstract TiO2–SiO2 mesoporous materials were synthesised by deposition of TiO2 nanoparticles prepared by the sol–gel method on to the internal pore surface of wormhole-like mesoporous silica. In this work we synthesised wormhole-like mesoporous silica of different surface area by changing the hydrothermal temperature (70, 100, or 130 C). Subsequent to this, titania solution was deposited on to the inner surface of the pores and this was followed by calcination at different temperatures (400, 600, or 800 C). The effect of different hydrothermal and calcination temperature on the photocatalytic properties was evaluated. The samples were characterized by N2-sorption, X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. The effect of different hydrothermal and calcination temperatures on the photocatalytic properties was evaluated by measuring the degradation of methylene blue in aqueous solution under UV light irradiation (mercury lamp, 125 W). The results indicated that appropriate surface area and degree of crystallinity are two important factors for obtaining high photocatalytic efficiency. Samples prepared at a hydrothermal temperature of 100 C and calcined at 800 C had the best photocatalytic performance, because of the highest surface area and high crystallinity.
Photocatalytic Degradation of Methylene Blue under UV Light Irradiation on Prepared Carbonaceous<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1">mml:mrowmml:msubmml:mrowmml:mtextTiOmml:mrowmml:mn2
The Scientific World Journal, 2014
This study involves the investigation of altering the photocatalytic activity of TiO 2 using composite materials. Three different forms of modified TiO 2 , namely, TiO 2 /activated carbon (AC), TiO 2 /carbon (C), and TiO 2 /PANi, were compared. The TiO 2 /carbon composite was obtained by pyrolysis of TiO 2 /PANi prepared by in situ polymerization method, while the TiO 2 /activated carbon (TiO 2 /AC) was obtained after treating TiO 2 /carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450 ∘ C. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TG-DTA), Brunauer-Emmet-Teller (BET), and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO 2 /AC > TiO 2 /C > TiO 2 /PANi > TiO 2 (179 > 134 > 54 > 9 m 2 g −1). The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.
2010
Photodegradation of methylene blue on a carbon-doped TiO 2 and on pure TiO 2 was studied. The materials were prepared by solvothermal synthesis and by calcinations. N 2 adsorption, XRD, SEM and TEM characterization was performed. Both nanomaterials exhibited mesoporous textures and the TiO 2 frameworks consist mainly of anatase phase. SEM images showed spherical microparticles while the TEM images showed hierarchically nanostructured morphologies on both samples. C-TiO 2 exhibited higher apparent first-order rate constants for the degradation of methylene blue than those obtained on pure TiO 2. It could be concluded that under visible light, the photoactivity of carbon-doped TiO 2 was clearly higher than that of a commercial TiO 2 photocatalyst suggesting that the carbon part photo assist the TiO 2 in the photodegradation of methylene blue.
Adsorption Science & Technology
Concerns have been increased regarding the existence of pollutants in environmental water resources and their risks to the ecosystem and human society. TiO2 photocatalyst is considered as an effective photocatalyst to remove the pollutants. Herein, the mesoporous TiO2-SBA-15 was prepared using the rice husk extract as the silica source. The fabricated nanocomposites were characterized using FTIR, small and wide angle XRD, Raman spectroscopy, UV-vis, BET surface area analysis, and HRTEM. The photocatalytic efficiency of the composites for the degradation of methylene blue (MB) has been evaluated under UV irradiation. Interestingly, due to the excellent dispersion of TiO2 on the wall of SBA-15 and good hydrophilicity, the nanocomposites displayed a good catalytic activity. The higher photodegradation performance was achieved by the composite containing 10 wt% TiO2 by which the MB was fully degraded within 15-20 min of irradiation. Besides, TiO2-SBA-15 could effectively inhibit the gro...
This study involves the investigation of altering the photocatalytic activity of TiO 2 using composite materials. Three different forms of modified TiO 2 , namely, TiO 2 /activated carbon (AC), TiO 2 /carbon (C), and TiO 2 /PANi, were compared. The TiO 2 /carbon composite was obtained by pyrolysis of TiO 2 /PANi prepared by in situ polymerization method, while the TiO 2 /activated carbon (TiO 2 /AC) was obtained after treating TiO 2 /carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450 ∘ C. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TG-DTA), Brunauer-Emmet-Teller (BET), and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO 2 /AC > TiO 2 /C > TiO 2 /PANi > TiO 2 (179 > 134 > 54 > 9 m 2 g −1). The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.
2014
TiO 2-SiO 2 composites containing 10 wt%, 20 wt%, 30% and 40 wt% of TiO 2 , obtained by using preformed mesoporous silica nanoparticles (MSNs) and titanium isopropoxide as titanium source, have been investigated in detail using a variety of techniques. All the samples were characterized by N 2physisorption, X-ray powder diffraction (XRPD), diffusive reflective UV-vis spectroscopy (DRUV-vis), X-ray photoelectron spectroscopy (XPS) and imaged using transmission electron microscopy (TEM). The TiO 2-MSN composites, that exhibited a spherical morphology, high specific surface areas and titania in the anatase phase, owing to their specific chemical-physical properties were studied as catalysts in the photocatalytic degradation of methylene blue, methyl orange and paracetamol, as examples of polluted wastewaters. The well-defined porous structures of MSNs may offer a special environment for titania nanoparticles, increasing the specific surface area and the thermal stability of the composite, thus modifying the photocatalytic behavior of the materials. The TiO 2 loading, the particle size and the surface characteristics were related to the degree of UV absorption and the measured energy band gap of the nanocomposites. A cooperative effect between the two components (TiO 2 and SiO 2) could be the key factor at the basis of the good photocatalytic performances: nanostructured TiO 2 in intimate contact with MSN provides the sites for generation of OHc radicals by oxidation of water and the SiO 2 skeleton is able to adsorb the molecules of cationic dyes and prevent poisoning of the TiO 2 surface.
Royal Society of Chemistry , 2019
In the present study, we synthesized several high-surface area V 2 O 5 /TiO 2-SiO 2 catalysts (vanado titanium silicate, VTS). The synthesized materials were characterized by PXRD, FE-SEM/EDAX, TEM, FTIR, UV-Vis, XPS, fluorescence and photocatalytic activity studies. The small-angle powder X-ray diffraction pattern shows that the 110 and 200 planes are merged to become a single broad peak. Field-emission scanning electron microscopy shows that the titanosilicate is spherical in shape and V 2 O 5 has a hexagonal rod-shaped morphology. The presence of various metal ions, such as V, Ti, Si and O, was observed by energy dispersive X-ray analysis and X-ray photoelectron spectroscopy. The transmission electron microscopy image shows clear hexagonal mesoporous fringes with V 2 O 5 distribution. The BET surface area analysis shows that the VTS catalysts have higher surface areas than pure V 2 O 5. Fourier transform infrared spectroscopic analysis shows the presence of Ti 4+ ions connected to the silanol groups. The bandwidths of pure titanosilicate, V 2 O 5 and their composites were calculated from their diffuse reflectance ultraviolet-visible spectra. The bandwidth was tuned by heterojunctions in the studied catalysts. The photoluminescence spectra of the VTS catalysts show a distinct behaviour as compared to those of the pure components. The photocatalytic activity of methylene blue degradation was determined with pure constituents and catalysts. VTS-1 (TS and VO weight ratio 2 : 1) shows higher conversion than other catalysts, pure titanosilicate and V 2 O 5. This is probably due to the heterojunctions and higher surface area in VTS-1. Kinetic studies reveal that direct sunlight shows higher activity than pure visible light. A plausible physical and chemical mechanism for the photocatalytic activity is proposed.