New Silica Supported Titanium Dioxide Catalysts: Characteristics and Photocatalytic Efficiency in Waste Water Depollution

2006 ◽  
Vol 61 (10) ◽  
pp. 1311-1318 ◽  
Author(s):  
Noureddine Kamil ◽  
Mohamed Khalid El Amrani ◽  
Najiba Benjelloun
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Inductively Coupled Plasma ◽  
Aqueous Suspension ◽  
Textile Dye ◽  
Photocatalytic Efficiency

Silica gel supported titanium dioxide photocatalysts were prepared by sintering TiO2/SiO2 mixtures under variations of TiO2 content, calcination temperature and calcination time. The method allowed to obtain catalyst samples, which can be used in aqueous suspension and which were found to be easily separated by decantation after the photocatalytic treatment. The photocatalytic efficiency of the catalysts was tested by carrying out the photooxidation of the textile dye Acid Red 88 (AR88) in aqueous solution, used as “model” water pollutant. The obtained photoefficiency results were correlated to catalyst physicochemical characteristics, as determined by Inductively Coupled Plasma (ICP) analysis, X-ray diffraction, specific surface area (BET) and scanning electron microscopy (SEM). No positive correlation has been observed between titanium dioxide content and photocatalytic efficiency. The decrease of photocatalytic activity at high calcination temperature (1000 °C) is attributed to the phase transition anatase/rutile as well as to the decreasing specific surface area. According to SEM analysis, no significant fixation of TiO2 on silica is observed for catalysts prepared at low temperature (400 °C). The observed photocatalytic activity is consequently due to free TiO2 particles. The best efficiency is observed for photocatalyst prepared at 800 °C and containing around fifty percent titanium dioxide.

Effect of Anatase/Rutile Phase Ratio on the Photodegradation of Methylene Blue under UV Irradiation

2020 ◽  
Vol 998 ◽  
pp. 78-83
Author(s):  
Yi Yi Zaw ◽  
Du Ang Dao Channei ◽  
Thotsaphon Threrujirapapong ◽  
Wilawan Khanitchaidecha ◽  
Auppatham Nakaruk
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Band Gap ◽  
Surface Area ◽  
Calcination Temperature ◽  
Organic Compounds ◽  
Specific Surface Area ◽  
Uv Irradiation ◽  
Rutile Phase

Titanium dioxide (TiO2) is known as one of the widely used catalysts in photocatalysis process. Recently, the photocatalysis of TiO2 has been implied in water purification and treatment, particularly dyes and organic compounds degradations. Naturally, the TiO2 can be found in three phases including anatase, rutile and brookite; each phase has its own specific properties such as grain size, stability and band gap energy. In this work, the effect of calcination temperature on the structure, morphology and photocatalytic activity were investigated. The data suggested that the anatase/rutile ratio of TiO2 can be controlled through the calcination process. The phase transformation data strongly indicated the liner function between percentage of rutile phase and calcination temperature. The BET analysis provided the consistent data with XRD patterns by showing that the specific surface area was decreased by increasing calcination temperature. The photodegradation of methylene blue under UV irradiation proved that the mixed phase of anatase/rutile ratio at 78.5/21.5 provided the highest photocatalytic activity. The phase composition ratio can influence the nanoparticles properties including band gap, specific surface area and energy band structure. Therefore, the control of anatase/rutile ratio was an alternative to enhance the photocatalytic activity of TiO2 nanoparticles for dyes and organic compounds degradations.

scholarly journals Photocatalytic degradation of metoxuron in aqueous suspensions ofTiO2. Analytical and kinetic studies

2002 ◽  
Vol 4 (4) ◽  
pp. 147-151 ◽  
Author(s):  
Amina Amine Khodja ◽  
Bernadette Lavedrine ◽  
Claire Richard ◽  
Tahar Sehili
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Kinetic Studies ◽  
Photocatalytic Efficiency ◽  
Aqueous Suspensions ◽  
Degussa P25 ◽  
Ring Hydroxylation

The photocatalytic degradation of metoxuron [3-(3-chloro-4-methoxyphenyl)-1,1-dimethylurea] in aqueous suspensions ofTiO2was investigated. Several intermediate photoproducts were identified using NMR and MS techniques. Oxidation or removal of the methyl of terminal nitrogen and ring hydroxylation were found to occur. 2-Propanol was shown to decrease the rate of photocatalytic degradation, inhibiting partly ring hydroxylation and completely reactions on terminal nitrogen. In contrast, basification of the suspensions accelerated the degradation significantly. Degussa P25TiO2was found to exhibit a higher photocatalytic activity than MillenniumTiO2in spite of a generally smaller specific surface area. Within the MillenniumTiO2series, the photocatalytic efficiency increased with the specific surface area.

scholarly journals Combination of mesoporous titanium dioxide with MoS2 nanosheets for high photocatalytic activity

2017 ◽  
Vol 19 (2) ◽  
pp. 56-60 ◽  
Author(s):  
Loghman Karimi
Keyword(s):  
Electron Microscopy ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Dye Degradation ◽  
Hydrothermal Process ◽  
Bet Analysis ◽  
Mesoporous Titanium Dioxide

Abstract This study presents a facile approach for the preparation of MoS2 nanosheet decorated by porous titanium dioxide with effective photocatalytic activity. Mesoporous titanium dioxide nanostructures first synthesized by a hydrothermal process using titanium (III) chloride and then the MoS2/TiO2 were prepared through mixing of MoS2 nanosheet with mesoporous titanium dioxide under ultrasonic irradiation. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) analysis. The results showed that the nanocomposite has mesoporous structure with specific surface area of 176.4 m2/g and pore diameter of 20 nm. The as-prepared MoS2/TiO2 nanocomposites exhibited outstanding photocatalytic activity for dye degradation under sunlight irradiation, which could be attributed to synergistic effect between the molybdenum disulfide nanosheet and mesoporous titanium dioxide. The photocatalytic performance achieved is about 2.2 times higher than that of mesoporous TiO2 alone. It is believed that the extended light absorption ability and the large specific surface area of the 2D MoS2 nanosheets in the nanocomposite, leading to the enhanced photocatalytic degradation activity.

scholarly journals Titanium dioxide modified with manganese: physicochemical and photocatalytic properties

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 214-218
Author(s):  
S. A. Safaryan ◽  
◽  
M. L. Belikov ◽  
V. A. Krysanova ◽  
◽  
...  
Keyword(s):  
Methylene Blue ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Phase Composition ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Organic Dyes ◽  
Photocatalytic Properties

The article presents the results of the studies of the physicochemical and photocatalytic properties of titanium dioxide modified with manganese, by the example of decomposition of organic dyes — ferroin and methylene blue. The correlations between the specific surface area and phase composition of the composites with their photocatalytic activity are revealed.

scholarly journals Enhanced Photocatalytic Activity for Degradation of Methyl Orange over Silica-Titania

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Yaping Guo ◽  
Shaogui Yang ◽  
Xuefei Zhou ◽  
Chunmian Lin ◽  
Yajun Wang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Photoelectron Spectroscopy ◽  
Anatase Phase ◽  
Solution Treatment ◽  
X Ray

Silica-modified titania (SMT) powders with different atomic ratios of silica to titanium (Rx) were successfully synthesized by a simple ultrasonic irradiation technique. The prepared samples were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet visible spectroscopy. The specific surface area was measured according to BET theory. Results indicate that the addition of silica to titania can suppress the crystalline size growth and the transformation of anatase phase to rutile phase of titania, enlarge specific surface area of the titania particles, and result in a blue shift of absorption edge compared to pure titania. The photocatalytic activity of the SMT samples was evaluated by decolorizing methyl orange aqueous solutions under UV-visible light irradiation. It was found in our study that this activity was affected by silica content, calcination temperature, H2SO4, and oxidants such as KIO4, (NH4)2S2O8and H2O2. The results reveal that the photocatalytic activity of 0.1-SMT catalyst is the best among all samples calcined at550°C for 1 h and it is 1.56 times higher than that of Degussa P-25 titania, which is a widely used commercial TiO2made by Germany Degussa company and has been most widely used in industry as photocatalyst, antiultraviolet product, and thermal stabilizer. The optimal calcination temperature for preparation was550°C. The photocatalytic activity of SMT samples is significantly enhanced by H2SO4solution treatment and oxidants.

scholarly journals Evaluation of the photocatalytic activity of concrete

2021 ◽  
Vol 6 (4) ◽  
pp. 13-20
Author(s):  
E. Krushel'nickaya
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Ultraviolet Radiation ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Concrete Surface ◽  
High Specific Surface Area ◽  
Foreign Manufacturer ◽  
Over Time

Based on the change in the color of an organic dye – rhodamine B, on the surface of concrete under the action of ultraviolet radiation, a theoretical and experimental assessment of the photocatalytic activity of concrete was carried out. Photocatalytic activity was calculated using the obtained coordinates of colorimetry L * a * b *. To assess the performance of the photocatalyst over time, a test was carried out with concrete samples at the age of 7 and 28 days. Titanium dioxide of three types of anatase modification of a foreign manufacturer was used as a photocatalyst in the study. It is shown that the introduction of titanium dioxide into concrete promotes self-cleaning of its surface. The values of discoloration of the dye on the concrete surface were obtained depending on its composition and on the time of exposure to ultraviolet radiation. It was determined that the value of the specific surface area of titanium dioxide affects the photocatalytic activity. It is noted that with the age of concrete samples, there is a noticeable decrease in phototransformation. It was also found that the high specific surface area of titanium dioxide allows it to exhibit its photocatalytic properties over time.

scholarly journals Photocatalytic activity of spectro-pure titanium dioxide: Effects of crystalline structure, specific surface area and sorption properties

2003 ◽  
Vol 5 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Evgeny I. Kapinus ◽  
Tatyana A. Khalyavka ◽  
Valentina V. Shimanovskaya ◽  
Tatyana I. Viktorova ◽  
Vladimir V. Strelko
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pure Titanium ◽  
Specific Rate ◽  
Two Phase ◽  
Photocatalytic Reactions ◽  
Optically Pure

Dispersed optically pure anatase, rutile and two-phase samples of titanium dioxide were prepared using a sol-gel technique. In particle of two-phase samples, the anatase nuclei are surrounded by a rutile envelope. Content of anatase in the two-phase particles varied between 20 and 80%. Particles of all theTiO2samples had a globular shape of diameter between 10 and 30μm. When compared to the corresponding technical-grade samples, the optically pure anatase and rutile demonstrated higher photocatalytic activity in the destruction of tetradecylpyridinium chloride, Methylene Blue and tetrachlorofluorescein as well as in reduction ofCr2O7,MnO4,[Fe(CN)6]3−and[Fe(CN)6]4−. The photocatalytic reactions bring about the reduction of the inorganic anions to yield water insoluble substances and mineralization of the organic compounds. Rate constant of the all above processes do not depend on specific surface area ofTiO2and adsorption of the substrates on theTiO2samples. The rutile calcined at 1027K exhibits the highest specific rate constants. Exposure toγ-radiation increases photocatalytic activity of the dispersedTiO2. The influence ofTiO2and substrate on the photocatalytic reactions is caused by the influence of these factors on the formation of reactive electron hole pair and on the efficiency of the interfacial electron transfer.

scholarly journals The Simplest Way to Iodine-Doped Anatase for Photocatalysts Activated by Visible Light

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Václav Štengl ◽  
Tomáš Matys Grygar
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Aqueous Suspension ◽  
Organometallic Compounds ◽  
Orange Ii ◽  
Iodine Doping ◽  
Doped Titania

Iodine-doped TiO2was prepared by thermal hydrolysis of aqueous solutions of the titanium peroxo-complex, which includes no organic solvents or organometallic compounds. The synthesized samples were characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), infrared spectroscopy (IR), specific surface area (BET), and porosity determination (BJH). The morphology and particle size was determined by high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). All prepared samples have a red-shifted band-gap transition, well crystalline anatase structure, and porous particles with a 100–200 m2 g−1specific surface area. The photocatalytic activity of iodine-doped titania samples was determined by decomposition of Orange II dye during irradiation at 365 nm and 400 nm. Iodine doping promotes the titania photocatalytic activity very efficiently under visible light irradiation. The titania sample with 0.32 wt.% I has the highest catalytic activity during the photocatalyzed degradation of Orange II dye in an aqueous suspension in the UV and visible regions.

scholarly journals Photocatalytic activity of BiFeO3/ZnFe2O4 nanocomposites under visible light irradiation

RSC Advances ◽  
2018 ◽  
Vol 8 (13) ◽  
pp. 6988-6995 ◽  
Author(s):  
B. Safizade ◽  
S. M. Masoudpanah ◽  
M. Hasheminiasari ◽  
A. Ghasemi
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Photocatalytic Efficiency

BiFeO3-25 wt% ZnFe2O4 exhibits a low specific surface area, high magnetization, and maximum photocatalytic efficiency of 97%.

scholarly journals Relationship between Synthesis Conditions and Photocatalytic Activity of Nanocrystalline TiO2

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Yosep Han ◽  
Hyung-Seok Kim ◽  
Hyunjung Kim
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Crystallite Size ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Molar Ratio ◽  
Hydroxyl Groups ◽  
Synthesis Conditions

The degradation efficiency of methylene blue by TiO2nanoparticles, which were synthesized under different synthesis conditions (i.e., molar ratio of water and titanium tetraisopropoxide (TTIP), pH, and calcination temperature) in a sol-gel process, was systematically investigated. The results showed that increasing the molar ratio of water and TTIP led to the enhanced photocatalytic activity of TiO2nanoparticles, which were likely attributed to the increased specific surface area of TiO2nanoparticles synthesized with high molar ratio. The results were supported by the relative increase in the size of interaggregated pores of the aggregated TiO2nanoparticles. The best photocatalytic activity of TiO2nanoparticles was observed at acidic synthesis conditions; however, the results were not consistent with physical properties for the crystallinity and the crystallite size of TiO2nanoparticles but rather explained by the presence of abundant hydroxyl groups and water molecules existing on the surface of TiO2under acidic synthesis environments. Furthermore, methylene blue degradation experiments revealed that the photocatalytic activity of TiO2nanoparticles was maximized at the calcination temperature of 700°C. The trend was likely due to the combined effect of the anatase crystallinity which showed the highest value at 700°C and the crystallite size/specific surface area which did not excessively increase up to 700°C.

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