Photocatalytic reduction of Cr(VI) in aqueous solution using TiO2 nanoparticles prepared with various alcohols as solvent

2012 ◽  
Vol 66 (6) ◽  
pp. 1333-1339 ◽  
Author(s):  
Young Ku ◽  
Chia–Nan Lin ◽  
Wei–Ming Hou
Keyword(s):  
Phase Transformation ◽  
Tio2 Nanoparticles ◽  
Surface Area ◽  
Hexavalent Chromium ◽  
Sol Gel ◽  
Photocatalytic Reduction ◽  
Structure Characterization ◽  
Phase Transformation Temperature ◽  
Reduction Activity ◽  
Sol Gel Process

TiO2 nanoparticles were prepared with various linear alkyl chains of alcohols under a sol–gel process. The structure characterization and the photocatalytic reduction of hexavalent chromium of the TiO2 nanoparticles were investigated. The phase transformation temperature, crystal aggregation and surface area of prepared TiO2 samples were found to be strongly influenced by alcohol used. The phase transformation from anatase to rutile was retarded and the surface area was reduced for TiO2 prepared with alcohols of longer alkyl chain. TiO2 nanoparticles prepared with methanol or ethanol exhibited higher photocatalytic reduction activity of hexavalent chromium possibly due to greater and more positively charged surface area.

scholarly journals Photocatalytic Reduction of AuCl4- by Fe3O4/SiO2/TiO2 Nanoparticles

2020 ◽  
Keyword(s):  
Tio2 Nanoparticles ◽  
Uv Light ◽  
Electronic Waste ◽  
Sol Gel ◽  
Photocatalytic Reduction ◽  
Light Illumination ◽  
Magnetite Fe3o4 ◽  
Sol Gel Process ◽  
Competitive Reduction ◽  
Closed Reactor

<p>Metallurgy and recovery of gold in electronic waste sometimes involve the reduction of tetrachloroaurate ion (AuCl4-) to elemental gold form. Currently, for the reduction of tetrachloroaurate ion, people use reducing agents such as hydroquinone and sodium borohydride. Photocatalysts of Fe3O4/SiO2/TiO2 nanoparticles were prepared and tested for the reduction of tetrachloroaurate ion under UV light illumination. The magnetite (Fe3O4) nanoparticle was first prepared by coprecipitation and sonication, followed by SiO2 and TiO2 coatings via the sol-gel process and calcination. The products were confirmed by XRD and TEM. The photocatalytic reduction of tetrachloroaurate ion was performed in a closed reactor equipped with a UV light source. The results indicated that Fe3O4/SiO2/TiO2 nanoparticles were successfully prepared, which retained good magnetic and photocatalytic properties. The photocatalytic reaction is best performed at a pH of 5 under UV irradiation for 2 h, which is capable of reducing 96% of the tetrachloroaurate present in the mixture. The co-presence of Ni2+ and Cu2+ ions in the solution leads to a decrease in yield due to competitive reduction and adsorption. The photocatalyst is recoverable by the use of a magnetic bar and may find application for gold recovery and metallurgy.</p>

Ultrahigh Surface Area Nanoporous Silica Particles via an Aero-Sol−Gel Process

Langmuir ◽  
2004 ◽  
Vol 20 (7) ◽  
pp. 2523-2526 ◽  
Author(s):  
S. H. Kim ◽  
B. Y. H. Liu ◽  
M. R. Zachariah
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Silica Particles ◽  
Nanoporous Silica ◽  
Sol Gel Process

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

One-Step Preparation of Viologen-TiO2 Nanoparticles via a Hydrothermally Assisted Sol-Gel Process for Use in Electrochromic Films and Devices

2018 ◽  
Vol 35 (11) ◽  
pp. 1800142 ◽  
Author(s):  
Ana Viñuales ◽  
Bettina Herbig ◽  
Yolanda Alesanco ◽  
Jesús Palenzuela ◽  
Javier Rodriguez ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Sol Gel ◽  
Sol Gel Process ◽  
One Step

scholarly journals Synthesis and Characterisation of Mesoporous TiO2 Nanoparticles by Novel Surfactant Assisted Sol-gel Method for the Degradation of Organic Compounds

2018 ◽  
Vol 63 (1) ◽  
pp. 85-95 ◽  
Author(s):  
Harish Phattepur ◽  
Gowrishankar Bychapur Siddaiah ◽  
Nagaraju Ganganagappa
Keyword(s):  
Electron Microscopy ◽  
Tio2 Nanoparticles ◽  
Surface Area ◽  
Sol Gel ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Tio2 Nps ◽  
Gel Method ◽  
X Ray ◽  
Surfactant Assisted

A sol-gel method was employed to synthesise pure titanium dioxide (TiO2) and surfactant assisted TiO2 nanoparticles (NPs). The effect of novel surfactant viz., Lauryl lactyl lactate on photocatalytic properties of TiO2 was studied. TiO2 NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-Vis Diffuse Reflectance spectra (DRS), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), Thermo gravimetric analysis (TGA), and Brunauer – Emmet - Teller (BET) surface area. Anatase phase of TiO2 was confirmed by X-Ray diffraction pattern and the crystallite size was between 9–19 nm. Addition of surfactant improved the BET surface area, surface defects, while the agglomeration of particles was reduced. DRS results revealed that the addition of surfactant to TiO2 sol induced a red shift of the absorption edge which resulted in the reduction of band gap from 3.23 to 3.21 eV. These physicochemical properties of TiO2 NPs were correlated with photocatalytic degradation of phenol. About 92% of phenol degradation was observed for surfactant assisted TiO2 NPs (SA-TiO2). Salicylic acid and caffeine were also degraded using SA-TiO2 NPs.

Preparation and Characterization of Phloroglucinol-Resorcinol-Formaldehyde Carbon Aerogels

2013 ◽  
Vol 423-426 ◽  
pp. 523-527
Author(s):  
Xuan Liu ◽  
Zhen Fa Liu ◽  
Hao Lin Fu ◽  
Rui He ◽  
Li Hui Zhang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
High Specific Surface Area ◽  
Carbon Aerogels ◽  
Resorcinol Formaldehyde ◽  
Sol Gel Process ◽  
Solvent Replacement ◽  
Organic Aerogels

Phloroglucinol-resorcinol-formaldehyde organic aerogels (PRF) were prepared using phloroglucinol, resorcinol and formaldehyde in a sol-gel process, solvent replacement and drying at room temperature. The phloroglucinol-resorcinol-formaldehyde carbon aerogels (CPRF) were prepared by charring the PRF at high temperature under the aegis of helium flow. The microstructure of CPRF was characterized by infrared spectroscopy, specific surface area analyzer and scanning electron microscopy. The results showed that the CPRF had continuous network structure and high specific surface area.

Preparation And Characterization Of Ultra-Small Sized Metal And Semiconductor Particles In Sol-Gel Materials

1994 ◽  
Vol 346 ◽  
Author(s):  
Kyung Moon Choi ◽  
Kenneth J. Shea
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Sol Gel ◽  
High Vacuum ◽  
Particle Sizes ◽  
Transition Metal Clusters ◽  
Surface Areas ◽  
Sol Gel Process ◽  
Bridged Silsesquioxanes

ABSTRACTPoly(l,4-phenylene)-bridged and poly(1,6-hexylene)-bridged silsesquioxanes (PPS and HPS) were prepared by the sol-gel process. The surface areas and pore diameters of these porous xerogels were obtained by BET and BJH methods, respectively. These porous materials were used as a confinement matrix for the growth of small-sized semiconductor and transition metal clusters. Quantum-sized CdS particles in PPS (approximately 58+12 Â) and HPS (91+16 Â) matrices were prepared by first soaking the xerogel in a CdCl2 solution. Following a washing with water, a Na2S solution was then added. EDAX and electron diffraction techniques were used to identify the CdS particles. The particle sizes of CdS in PPS and HPS were determined by both UV measurements and from TEM images. Small-sized Cr clusters were prepared in dried xerogels by an internal doping method. Mixed Cr/CdS phases were also prepared by internal loading of a chromium metal precursor. Following deposition of CdS the xerogel was heated at 120 °C under high vacuum, resulting in formation of intimately mixed phases of Cr metal and CdS. Changes in morphology, in particular the surface area and pore size distribution were noted. A decrease in surface area and an increase in pore size were observed as a result of Cr metal deposition.

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

2012 ◽  
Vol 519 ◽  
pp. 83-86 ◽  
Author(s):  
Guang Wu Liu ◽  
Xing Yuan Ni ◽  
Bin Zhou ◽  
Qiu Jie Yu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

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