Siliceous Materials for Immobilization of Photoheterotrophic Bacteria

2011 ◽  
Vol 1326 ◽  
Author(s):  
Mikolaj Stodolny ◽  
Michal Thiel ◽  
Marcin Wlodarczak ◽  
Marek Laniecki
Keyword(s):  
Hydrochloric Acid ◽  
Surface Area ◽  
Organic Compounds ◽  
Photosynthetic Bacteria ◽  
Pore Diameter ◽  
Potato Starch ◽  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Commercial Potato ◽  
Vis Spectroscopy

ABSTRACTPreparation of transparent silica as potential carrier for photocatalysts and photosynthetic bacteria is presented. SiO2 was obtained by sol-gel techniques using tetraethyl orthosilicate as precursor. Glycol and glycerol were used as solvents. The increase of porosity of the studied materials was reached by application of soluble and commercial potato starch as a filler. Calcinations at 825 K for 6 hours removed all organic compounds. The rate of gelation was enhanced applying hydrochloric acid. Different materials were obtained in a series of syntheses with different concentrations of individual components. Transparency of the obtained materials varied between 50 and 97% (in range of λ 350 - 800 nm). Surface area varied between 300 and 400 m2/g and pore diameter was 5 – 18 nm. Samples were studied with SEM, nitrogen sorption at 77 K and UV-Vis spectroscopy. The obtained transparent materials with occluded TiO2 or CaTiO3 were tested in photocatalytic splitting of water.

scholarly journals Photocatalytic activity of Pr-modified TiO2 for the degradation of bisphenol A

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Denise S. Cordeiro ◽  
Fernando L. Cassio ◽  
Larissa Ciccotti ◽  
Thiago L. R. Hewer ◽  
Paola Corio ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Bisphenol A ◽  
Pore Diameter ◽  
Sol Gel ◽  
Bandgap Energy ◽  
Photocatalytic Efficiency ◽  
Average Pore ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Adsorption Desorption

AbstractPraseodymium doped TiO2 nanoparticles were successfully prepared by the sol–gel method and characterized by X-ray powder diffraction, N2 adsorption–desorption isotherm, and UV–vis spectroscopy. The effects of the dopant on the crystallite size, specific surface area, average pore diameter, pore volume, and bandgap energy were investigated. The photocatalytic activity of the catalysts was evaluated by bisphenol A degradation and mineralization, which is a representative endocrine disruptor. Furthermore, under visible light irradiation the Pr-modified TiO2 photocatalysts exhibited higher photocatalytic efficiency than unmodified TiO2. When praseodymium was loaded (1.0–5.0%) onto the surface of TiO2, the rates of degradation and mineralization were increased 3–5 times.

Photocatalytic Efficiency for Dye Decolorization of the UV/TiO2, UV/TiO2 + In2O3 and UV/TiO2-In2O3 Systems

2013 ◽  
Vol 831 ◽  
pp. 263-266
Author(s):  
Chung Hsin Wu ◽  
Chao Yin Kuo ◽  
Chih Hao Lai ◽  
Wei Yang Chung
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Dye Decolorization ◽  
X Ray Diffraction ◽  
First Order ◽  
First Order Kinetics ◽  
Vis Spectroscopy ◽  
Reactive Red 2

This study explored the decolorization of C.I. Reactive Red 2 (RR2) by the ultraviolet (UV)/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems. The TiO2-In2O3 was generated by the sol-gel method and TiO2 + In2O3 was created by mixing TiO2 and In2O3 powders. The surface properties of TiO2, In2O3, and TiO2-In2O3 were analyzed by X-ray diffraction, a specific surface area analyzer, UV-vis spectroscopy, and scanning electron microscopy. The specific surface area of TiO2, In2O3, and TiO2-In2O3 was 29.5, 44.6, and 35.7 m2/g, respectively; additionally, the band gap of TiO2, In2O3, and TiO2-In2O3 was 2.95, 2.64, and 2.91 eV; respectively. The decolorization rate constant fit pseudo-first-order kinetics and that of the UV/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems was 0.0023, 0.0031, and 0.0072 min-1; respectively.

scholarly journals Design and Photocatalytic Activity of Mesoporous TiO2/ZrO2 Thin Films

2005 ◽  
Vol 23 (6) ◽  
pp. 497-508 ◽  
Author(s):  
Yu. Gnatyuk ◽  
N. Smirnova ◽  
A. Eremenko ◽  
V. Ilyin
Keyword(s):  
Thin Films ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Surface Acidity ◽  
Sol Gel ◽  
Pluronic P123 ◽  
Vis Spectroscopy ◽  
Gel Technique ◽  
Doped Titania

Optically transparent, crack-free mesoporous titania and zirconia-doped titania thin films were fabricated by the sol—gel technique using the non-ionic amphiphilic triblock copolymer Pluronic P123 as the template. The structure and optical properties of these films were characterized using TEM, low-angle XRD, DTA/TG measurements, UV—vis spectroscopy and hexane adsorption investigations. It was found that addition of ZrO2 into the TiO2 matrix retarded sintering of the films, thereby increasing the specific surface area after treatment up to 500°C. The catalytic activity of the mesoporous TiO2 and TiO2/(5–30%) ZrO2 films in ethanol photo-oxidation increased with increasing specific surface area and surface acidity of the samples.

Synthesis of Nanostructured Tin Oxide by Sol–Gel and Sonochemical Approaches in an Ionic Liquid

2018 ◽  
Vol 232 (2) ◽  
pp. 245-256 ◽  
Author(s):  
Hala K. Farag ◽  
Hussein Abbas
Keyword(s):  
Ionic Liquid ◽  
Surface Area ◽  
Tin Oxide ◽  
Pore Diameter ◽  
Sol Gel ◽  
Sonochemical Method ◽  
Average Pore ◽  
Gel Method ◽  
Sol Gel Method ◽  
Tin Oxide Nanoparticles

AbstractThe present paper shows a comparative study on the synthesis of nanostructured tin oxide in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO) by sol–gel and sonochemical methods. The XRD results of the synthesized materials revealed the formation of single tetragonal phase of SnO2by sol–gel method whereas a mixture of tetragonal SnO and orthorhombic SnO2phases was obtained by the sonochemical method. The sonochemical approach led to the formation of finer nanoparticales with a higher specific surface area than that of the sol–gel synthesized oxide. The average sizes of tin oxide nanoparticles were found to be about 30 nm and 15 nm for the particles obtained by sol–gel and sonochemical methods, respectively. The surface area of SnO2nanopowder obtained by the sol–gel method (calcined at 500 °C) was estimated to be 11.6 m2g−1, and the mean pore diameter was found to be 6.33 nm. Whereas the mixed SnO/SnO2sample (calcined at 500 °C) obtained by the sonochemical method exhibited a higher surface area of 43.11 m2g−1and an average pore diameter of 1.90 nm. The band gap of the synthesized tin oxides was estimated from the UV-vis. results to be 4.01 and 4.25 eV for the sol–gel and sonochemically synthesized samples, respectively.

The Preparation and Characterization of the Mesoporous Poly(bisphenol-A carbonate) – Silica Nanocomposites

2014 ◽  
Vol 513-517 ◽  
pp. 82-85
Author(s):  
Rui Rui Li ◽  
Yue Shi ◽  
Lei Zu ◽  
Hui Qin Lian ◽  
Yang Liu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Ph Value ◽  
Sol Gel ◽  
Synthesis System ◽  
Silica Nanocomposites

The mesoporous polycarbonate-silica nanocomposite materials were synthesized through the modified sol-gel approach under acidic condition. The specific surface area, pore diameter and pore volume of polycarbonate-silica could be controlled by changing the acidity of the synthesis system. The polycarbonate-silica possess an irregular block morphology according to the scanning electron microscopy observations. With decreasing the pH value of the synthesis system, the specific surface area and pore diameter of polycarbonate-silica were raised but the pore volume was reduced. The maximum specific surface area of polycarbonate-silica was 701.71m2/g which presented by the results of Nitrogen adsorptiondesorption isotherms.

Influence of Hydrolysis Rate on Properties of Nanosized TiO2 Synthesized via Sol-Gel Hydrothermal

2015 ◽  
Vol 1109 ◽  
pp. 286-290 ◽  
Author(s):  
Robabeh Bashiri ◽  
Norani Muti Mohamed ◽  
Chong Fai Kait ◽  
Suriati Sufian
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Area Measurement ◽  
Hydrolysis Rate ◽  
Molar Ratio ◽  
Titanium Tetraisopropoxide ◽  
Transmission Electron Microscopy Analysis ◽  
Molar Ratios ◽  
Vis Spectroscopy

This paper presents the effect of different H2O: TTIP (Titanium tetraisopropoxide) molar ratios of 8 to 64 during the synthesis using sol-gel associated hydrothermal method on the physical properties. Characterization of all synthesized TiO2 were accomplished by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and total surface area measurement, transmission electron microscopy analysis (TEM) and diffuse reflectance UV–Vis spectroscopy (DR-UV-Vis). The XRD analysis showed that anatase (101) was the major phase for all photocatalysts as verified by TEM results. The growth of crystallites with sizes ranging between 10 to 12 nm can be controlled by adjusting the H2O: TTIP molar ratios. Furthermore, no phase transformation from anatase to rutile observed by increasing the H2O: TTIP molar ratio. BET data displayed that all prepared photocatalysts are mesoporous materials with type IV adsorption behaviour. DR-UV-Vis spectroscopy revealed that the hydrolysis rate does not give any significant changes on the band gap energies. Among different photocatalysts, the prepared photocatalyst with the H2O: TTIP molar ratio 32 had the smallest crystal size, particle size, and the highest surface area which are suitable for better photocatalytic performance.

Sol-Gel Synthesis of N-Doped Mesoporous TiO2 with High Crystallinity and High Visible Light Photocatalytic Activity

2012 ◽  
Vol 217-219 ◽  
pp. 857-861 ◽  
Author(s):  
Xiao Ling Guo ◽  
Xiang Dong Wang ◽  
Feng He
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Surface Area ◽  
Anatase Phase ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Weight Ratio ◽  
Mesoporous Tio2 ◽  
Vis Spectroscopy

N-doped mesoporous TiO2 with high surface area and crystallinity were synthesized by sol-gel method using polyacrylamide (PAM) and polyethylene glycol (PEG) as the complex templates. The resulting materials were characterized by XRD, TEM, N2 adsorption-desorption, and UV-Vis spectroscopy. It is found that when the weight ratio of PAM and PEG is 1:4, the sample, prepared at 600 °C in nitrogen and at 500 °C in air, is anatase phase and has high surface area and crystallinity. The particle size and pore size of the sample are about 10 nm and 17 nm respectively. Compared with that of the undoped mesoporous TiO2, the absorption band edges of N-doped samples exhibit an evident red-shift. The results of the photocatalytic degradation of methyl orange (MO) show that N-doped sample appears to have higher photocatalytic activity under visible light than undoped sample.

The Degradation and BMP Release Dynamics of Silica-Based Xerogels Modified by Adding Calcium and Magnesium or Sintering Process

2012 ◽  
Vol 151 ◽  
pp. 378-382 ◽  
Author(s):  
Xiao Sheng Li ◽  
Wei Lin ◽  
Feng Lan Xing
Keyword(s):  
Electron Microscope ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Diameter ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Silica Xerogel ◽  
Calcium And Magnesium

A new mesoporous silica xerogel used as biodegradable material was synthesized by improved sol-gel methods. The xerogel’s degradation character and property of releasing character for bone morphological protein (BMP)were modified by adding calcium (Ca) and phosphor (P) elements into pure silica xerogel, and uesing sintering processes, as well as adding magnesium (Mg) into silica xerogel. The differential thermal and thermogravimetric analysis (DTA-TG), X-Ray diffraction analysis(XRD), Fourier infrared spectrum analysis (FITR), N2 adsorption-desorption analysis, Scanning electron microscope(SEM) and Transmitting electron microscope (TEM) observation were used to measure the thermal effects, crystalline state, pore diameter and specific surface area, surface morphology and inner structure of the xerogels. The xerogel’s degradability and BMP release were studied by simulated body fluid (SBF) immersion. The results indicated that the synthesized xerogels were mesoporous structure with pore diameter around 3 nm and the big specific surface area about 1000 m2/g.They were non crystall with hydroxyl and micro-molecular silica-oxygen groups. Xerogels dried at low sintering temperature degraded completely in 42 days in bursting manner and degraded in linear curves with sintering temperature increased as well as adding calcium and magnesium into xerogels. The BMP release behaviour from the Mg-xerogel dried naturally was in controlled manner.

scholarly journals Effect of the Preparation Method (Sol-Gel or Hydrothermal) and Conditions on the TiO2 Properties and Activity for Propene Oxidation

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2227 ◽  
Author(s):  
Laura Cano-Casanova ◽  
Ana Amorós-Pérez ◽  
María Lillo-Ródenas ◽  
María Román-Martínez
Keyword(s):  
Heat Treatment ◽  
Surface Area ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Propene Oxidation ◽  
Vis Spectroscopy ◽  
Post Synthesis ◽  
Adsorption Desorption ◽  
Hydrolysis Of ◽  
Selection Of

Since the two most commonly used methods for TiO2 preparation are sol-gel (SG) and hydrothermal (HT) synthesis, this study attempts to compare both methods in order to determine which one is the most suitable to prepare photocatalysts for propene oxidation. In addition, this work studies how the concentration of the HCl used for hydrolysis of the TiO2 precursor affects the properties of the obtained materials. Also, the effect of avoiding the post-synthesis heat-treatment in a selection of samples is investigated. The photocatalysts are characterized by XRD, N2 adsorption-desorption isotherms and UV-vis spectroscopy, and the study tries to correlate the properties with the photocatalytic performance of the prepared TiO2 samples in propene oxidation. TiO2 materials with high crystallinity, between 67% and 81%, and surface area (up to 134 m2/g) have been obtained both by SG and HT methods. In general, the surface area and pore volume of the TiO2-HT samples are larger than those of TiO2-SG ones. The TiO2-HT catalysts are, in general, more active than TiO2-SG materials or P25 in the photo-oxidation of propene. The effect of HCl presence during the TiO2 synthesis and of the post synthesis heat treatment are much more marked in the case of the SG materials.

Preparation of Silicon Dioxide Fiber via Sol-Gel Process

2008 ◽  
Vol 368-372 ◽  
pp. 794-796
Author(s):  
Xiao Hui Wang ◽  
Xiao Ping Liang ◽  
Shao Bo Xin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrochloric Acid ◽  
Silicon Dioxide ◽  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Molar Ratio ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Scanning Electron

Silicon dioxide gel fibers were prepared by hydrolysis reaction of tetraethyl orthosilicate (TEOS). TEOS was used as basic materials, anhydrous ethanol (EtOH) as solvent and hydrochloric acid (HCl) as the catalyst. The best proportion of the chosen materials (TEOS, EtOH, H2O and HCl) was 1:1:1.5:0.03(molar ratio).Gel fibers were investigated by thermogravimetry (TG). Silicon dioxide fibers were obtained by treating the gel fibers at different temperatures. The calcined fibers were characterized by scanning electron microscopy (SEM). The optimal sintering schedule was obtained. Silicon dioxide fiber dried at 200°C for 1 hour then calcined at 800°C for 3 hours was the best.

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