Particle Size Of TiO2 Research Articles

Automobile Exhaust Removal Performance of Pervious Concrete with Nano TiO2 under Photocatalysis.

The urban environment is facing serious problems caused by automobile exhaust pollution, which has led to a great impact on human health and climate, and aroused widespread concern of the government and the public. Nano titanium dioxide (TiO2), as a photocatalyst, can be activated by ultraviolet irradiation and then form a strong REDOX potential on the surface of the nano TiO2 particles. The REDOX potential can degrade the automobile exhaust, such as nitrogen oxides (NOx) and hydrocarbons (HC). In this paper, a photocatalytic environmentally friendly pervious concrete (PEFPC) was manufactured by spraying nano TiO2 on the surface of it and the photocatalytic performance of PEFPC was researched. The nano TiO2 particle size, TiO2 dosage, TiO2 spraying amount, and dispersant dosage were selected as factors to investigate the efficiency of photocatalytic degradation of automobile exhaust by PEFPC. Moreover, the environmental scanning electron microscope (ESEM) was used to evaluate the distribution of nano TiO2 on the surface of the pervious concrete, the distribution area of nano TiO2 was obtained through Image-Pro Plus, and the area ratio of nano TiO2 to the surface of the pervious concrete was calculated. The results showed that the recommended nano TiO2 particle size is 25 nm. The optimum TiO2 dosage was 10% and the optimum dispersant dosage was 5.0%. The photocatalytic performance of PEFPC was best when the TiO2 spraying amount was 333.3 g/m2. The change in the photocatalytic ratio of HC and NOx is consistent with the distribution area of nano TiO2 on the surface of the pervious concrete. In addition, the photocatalytic performance of PEFPC under two light sources (ultraviolet light and sunlight) was compared. The results indicated that both light sources were able to stimulate the photocatalytic performance of PEFPC. The research provided a reference for the evaluation of automobile exhaust removal performance of PEFPC.

Simulating the wet granulation of TiO2 photocatalyst in fluidized bed: Population balance modelling and prediction of coalescence rate

The major focus of this study, the second part of a series, is to simulate the net granulation process of TiO2 powder using 1-D discretized population balance modelling (PBM) and Size-Independent Kernel (SIK) coalescence model. In this, sequential and non-sequential modelling procedures have been used.Tested one-dimensional population balance model and coalescence-only, size-independent kernel provide a good prediction of real TiO2 particle size distributions (PSDs). The coalescence rate is quantified for both modelling procedures and formulation system used. Reduced-order population balance equation (PBE) and quite simple, fully empirical coalescence-only kernel successfully describe and predict real TiO2 PSDs. This paper reveals the meso-scale study of the wet granulation process for the not previously granulated powder system.

Self-assembling TiO2 on aminated graphene based on adsorption and catalysis to treat organic dyes

Aminated graphene oxide (NGO) was synthesized by condensation of graphene oxide (GO) and diethylenetriamine (DETA). Highly catalytic nanostructured NGO-TiO2 composite catalysts were self-assembled by a two-phase system of toluene and water. The crystal structure, morphology, and optical properties of the composite catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectrometry (UV–Vis) and so on. The degradation of methyl orange dye under simulated solar illumination was used to evaluate the performance of the composite catalysts. Though the particle size of the commercial TiO2 used in the work was larger than that synthesized in the laboratory, the NGO-TiO2 catalyst had better performance than the TiO2 and GO-TiO2 prepared in the same way, and the catalytic performance of NGO-TiO2 improved with increasing NGO loading amount in an appropriate ratio. The mechanism by which NGO improves the TiO2 performance was fully explained from a new perspective. The introduction of NGO not only improves the catalytic performance of TiO2 but also solves the posttreatment problem of relying on adsorption to deal with pollutants.

Insights into mesoporous MCM-41-supported titania decorated with CuO nanoparticles for enhanced photodegradation of tetracycline antibiotic.

In this research, tetracycline photodegradation under UV light was investigated over bare TiO2 and a series of MCM-41 supported CuO-TiO2 heterojunctions varying in CuO content with the intent of exploring the effect of MCM-41 presence and especially, CuO addition. Several techniques including XRD, FESEM, EDX, DRS, BET, and PL were applied to characterize the physicochemical and photophysical properties of synthesized nanocomposites. It was found that the co-existence of MCM-41 and CuO enhances the surface dispersion of Ti species, leading to less number of agglomerates and smaller particle size of TiO2, which it promoted photophysical properties and reinforced the interaction of surface species with the support and thereby, the photosite leachings were lessened. However, the excessive loadings alleviate the synergetic effect of CuO due to the significant decrease of surface area, the appearance of more number of agglomerations, and surface coverage of MCM-41. The results revealed that CuO addition not only enhances the photocatalytic activity of TiO2/MCM-41 but also makes it reusable in further experiments. It was also observed that the highest photodegradation of tetracycline was obtained over TiO2-CuO/MCM-41 nanocomposite containing 5 wt% CuO. It is attributed to less electron-hole recombination, appropriate band gap, smaller number of agglomerations, and more uniform dispersion of photosites. Following the obtained results, a possible reaction mechanism was also proposed.

Potential of TiO2 with Various Au Nanoparticles for Catalyzing Mesotrione Removal from Wastewaters under Sunlight.

Nowadays, great focus is given to the contamination of surface and groundwater because of the extensive usage of pesticides in agriculture. The improvements of commercial catalyst TiO2 activity using different Au nanoparticles were investigated for mesotrione photocatalytic degradation under simulated sunlight. The selected system was 2.43 × 10−3% Au–S–CH2–CH2–OH/TiO2 (0.5 g/L) that was studied by transmission electron microscopy and ultraviolet-visible (UV-Vis) spectroscopy. It was found that TiO2 particles size was ~20 nm and ~50 nm, respectively. The Au nanoparticles were below 10 nm and were well distributed within the framework of TiO2. For 2.43 × 10−3% Au–S–CH2–CH2–OH/TiO2 (0.5 g/L), band gap energy was 2.45 eV. In comparison to the pure TiO2, addition of Au nanoparticles generally enhanced photocatalytic removal of mesotrione. By examining the degree of mineralization, it was found that 2.43 × 10−3% Au–S–CH2–CH2–OH/TiO2 (0.5 g/L) system was the most efficient for the removal of the mesotrione and intermediates. The effect of tert-butanol, NaF and ethylenediaminetetraacetic acid disodium salt on the transformation rate suggested that the relative contribution of various reactive species changed in following order: h+ > ●OHads > ●OHbulk. Finally, several intermediates that were formed during the photocatalytic treatment of mesotrione were identified.

Development of Sunscreen Products Containing Titanium Dioxide and <i>Aloe vera</i> Gel

This study aimed to develop sunscreen emulsion from natural sunscreening agents, titanium dioxide and Aloe vera gel extract that have good sun protection efficacy. The effects of formulation variables i.e., particle size and amount of titanium dioxide, amount of Aloe vera gel extract (spray dried powder) and combination of sunscreening agents (titanium dioxide and Aloe vera gel extract) on physical properties and sun protection efficacy (e.g., SPF, UVA/UVB ratio, critical wavelength) of sunscreen products were evaluated. The results showed that the smaller particle size of titanium dioxide improved the sun protection efficacy and increased the UVB absorption edge of the products. SPF of the formulations could be ranked as Nanofine TiO2 (particle size 25–30 nm) > Kingruti T-01 TiO2 (particle size 200 nm) > Pigment TiO2 (particle size < 45,000 nm) and UVA/UVB ratio and critical wavelength of the formulations could be arranged in order as follows: Nanofine TiO2 < Kingruti T-01 TiO2 < Pigment TiO2. Increasing amount of titanium dioxide from 5 to 15 %w/w increased significantly viscosity and SPF of formulations. Aloe vera gel extract itself did not significantly affect SPF, however, combination of Aloe vera gel extract and titanium dioxide seemed to have synergistic effect on sun protection efficacy and decreased viscosity of the formulation. According to the results, the good sunscreen formulation consisted of 15 %w/w Nanofine TiO2, 5 %w/w Aloe vera gel spray dried powder in emulsion base because it was broad spectrum sunscreen and showed high SPF (27.53±1.92), high UVA/UVB ratio with critical wavelength higher than 370 nm.

Synthesis of TiO2/reduced graphene oxide–Al2O3 composites and their advanced properties for photocatalysis

The TiO2/reduced graphene oxide (RGO)-Al2O3 composites were synthesized by dispersing TiO2 on RGO-modified Al2O3 by impregnation method. The surface properties of TiO2/RGO–Al2O3 were systematically studied. It was found that the TiO2 particle size was about 15 nm, and the particles were relatively uniform in the loading range of 20–40 wt% compared with that of Al2O3. The surface area increased obviously as RGO was added to Al2O3. The chemical structures of the TiO2/RGO–Al2O3 composites were characterized by diffuse reflectance UV–Visible spectroscopy and X-ray photoelectron spectroscopy. Results revealed the presence of an intense interaction between TiO2 and RGO–Al2O3. The dark adsorption results showed that the TiO2/RGO–Al2O3 had a higher adsorption ability for methyl orange (MO), which was mainly due to the π-π conjugation between MO and RGO. The liquid-phase photocatalytic oxidation of MO was adopted to evaluate the efficiency of the obtained materials. TiO2/RGO–Al2O3 showed higher catalytic efficiency over the TiO2/Al2O3 or the commercial P25 photocatalyst. Recycling tests showed excellent stability of TiO2/RGO–Al2O3. The TiO2/RGO–Al2O3 was easier to separate by filtration method than TiO2 due to its high anti-hydration dispersion ability. The studies indicated their good prospects for large-scale application.

The synthesis of TiO2 nanoparticles by Milling and Coprecipitation Mixed Method

Ilmenite type Fe 2 O 3 waste (which is processed from natural iron sand) was processed into TiO 2 nanoparticles powder carried out by leaching with HCl and then using high-energy milling (HEM) for 50 hours. The characteristics of the powder such as particle size, size distribution and phases were analyzed using various techniques such as XRD, SEM, EDS and particle size analyzer. Synthesis and characterization of ilmenite type iron sand have been successfully made into TiO 2 by milling and coprecipitation mixed method. The purity level of TiO 2 was obtained by 85.01%. Particle size of TiO 2 was approximately 500 nm.

Effects of nano-TiO2 particle size on microstructure and electrochemical performance of TiO2/PEDOT nanocomposites cathode in lithium-sulphur battery

ABSTRACT The PEDOT/TiO2 nanocomposites with different TiO2 particle sizes were fabricated by a simple soft chemical approach-assisted in situ synthesis route and used as an effective cathode of Li-S batteries. When the TiO2 particle size was 5 nm, the discharge capacity of the cells is the best and the initial discharge capacity is 859.7 mAhg−1, within 300 charge–discharge cycles at 1 C. The improvement on cells electrochemical performance is attributed to the TiO2 particles well dispersed in the PEDOT, and the PEDOT creates integral electronic conductive net-work and prevent soluble long-chain polysulphides diffuse into the liquid electrolyte during the charge–discharge processes.

Effect of TiO2 particle and pore size on DSSC efficiency

In this work, we report the preparation of TiO2 nanoparticles with a high surface area, from 120 to 168 m2 g−1 by the hydrothermal-microemulsion route and hydrothermal temperature effect over particle size, porosity, and photovoltaic parameter. The TiO2 samples were characterized by Raman, BET, TEM, SEM-FE, I–V curves, and EIS. The increase of hydrothermal temperature correlates with particle and pore size. Although when the synthesis temperature was 250 °C, the surface area presents an unexpected decrease of c.a. 28%. TiO2 samples were employed as thin-film photo-anodes for dye-sensitized solar cell (DSSC) solar cells. Photovoltaic results showed that the sample prepared at 250 °C presented the more suitable textural properties for the DSSC application. The prepared TiO2 materials with a particle size of 6.93 ± 0.59 nm and anatase crystalline phase favor electron transport and diffusion of electrolyte species, which directly impact in solar cell efficiency.

Preparation of a microsphere SiO2/TiO2 composite pigment: The mechanism of improving pigment properties by SiO2

In this study, a microsphere SiO2/TiO2 composite pigment (M-SiO2/TiO2) was prepared through a facile grinding and calcination process. The structure and properties of M-SiO2/TiO2 were characterized in detail, and the mechanism governing the improvement of pigment properties by M-SiO2 was proposed. The results of this study show that M-SiO2 and TiO2 are successfully compounded, and their combination is inferred to be achieved by the formation of Si-O-Ti bonds through the hydroxyl groups on their surface. The M-SiO2/TiO2 has almost the same pigment properties as pure titanium dioxide, while the weight fraction of TiO2 in M-SiO2/TiO2 is 70%, which can significantly reduce the consumption of TiO2. In M-SiO2/TiO2, the introduction of M-SiO2 leads to the improvement of the rutile-phase conversion of TiO2, as well as reducing TiO2 particle size; thus, this step can further improve the pigment properties. When the calcination temperature is 900 °C, the TiO2 in M-SiO2/TiO2 is primarily rutile (rutile conversion rate is 88.57%) with a particle size of 0.1-0.3 μm, exhibiting good dispersion. In contrast, pure TiO2 is primarily composed of anatase (rutile conversion rate is 11.39%) with a particle size of 0.2-0.6 μm, exhibiting serious agglomeration. The M-SiO2/TiO2 composite is expected to be applied in the fields of paint, plastic, and papermaking in an effort to significantly reduce the cost and consumption of TiO2 pigment.

Determination of titanium dioxide nanoparticles used in various foods

ABSTRACT Titanium dioxide (TiO2) is commonly used in foods with code E171. There is information on the food packaging that it contains E171 in the ingredients section. However, there is no information on the amount of E171 used as ingredient. Therefore, determination of TiO2 content of foods is extremely important for human health. In this study, confectionary foods, chewing gums, chocolates and white colored foods were investigated. TiO2 levels of investigated foods were determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The average titanium dioxide concentrations were found ranging from 3 to 2400 mg kg-1. The size of TiO2 particles in the foods samples was determined with transmission electron microscopy (TEM). Titanium dioxide nanoparticles in the studied foods were found to vary in size from 30 to 410 nm.

UV-activated formaldehyde sensing properties of hollow TiO2@SnO2 heterojunctions at room temperature

Hollow TiO2@SnO2 nanospheres were synthesized via a hydrothermal process. Comparing to pure hollow TiO2 nanospheres, the hollow TiO2@SnO2 heterojunction nanospheres based sensor exhibited better sensing properties to formaldehyde under Ultraviolet (UV) irradiation at room temperature. The response time and recovery time were 20 s and 56 s, respectively, which are reduced compared to the pure one. The enhanced sensing properties could be ascribed to the formation of heterojunction between SnO2 and TiO2 together with hollow nanosphere architectures. The decorated TiO2 nanocrystals are even more depleted at the shallow Debye region which is equivalent to the reduction in the effective particle size of TiO2 significantly contributing to the enhanced response. After the targeted gases were removed, the chemisorbed oxygen on the surface of the metal oxides trapped electrons to the surface of the heterojunction sample. This process can also be promoted by energy barriers, which can explain the faster recovery speed of the heterojunction based sensor compared to that of the pure hollow TiO2 based one.

Efficient Immobilised TiO2 in Polyvinylidene fluoride (PVDF) Membrane for Photocatalytic Degradation of Methylene Blue

Immobilised titanium dioxide (TiO2) in membrane structures has recently become attractive. This is due to the elimination of the separation step after the process of photocatalytic degradation. The efficiency of the TiO2 surface area exposed to UV light as the main important parameter needs to be considered. The immobilisation of TiO2 nanoparticles in the polyvinylidene fluoride (PVDF) membrane structure with different particle sizes (6 nm and 30 nm) was prepared via various techniques including the tape casting and spin coating methods to study the distribution of TiO2 nanoparticles in the membrane structure. Besides, the effects of the spinning speed in spin coating methods on the membrane structure and photocatalytic performance were investigated. The morphological and physical characteristics were also explored by field emission scanning electron microscope (FESEM) energy dispersion of X-ray (EDX), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis. The prepared membranes were tested in a photocatalytic system using methylene blue (MB) as a model pollutant. The results showed that the immobilisation of TiO2 nanoparticles in membrane structure could enhance the rate of MB degradation. The aggregation of the 6 nm and 30 nm TiO2 particle sizes prepared by tape casting method shows similar performance in MB degradation rate but contradict the result of the spin coating method. The good distribution and uniformity of the 6 nm TiO2 particle size exhibit a higher MB degradation rate. The thickness of the membrane can be tailored using the spin coating method and UV penetration towards the photocatalytic membrane up to 55.64 μm of thickness, which could enhance the MB photocatalytic degradation rate.

Construction of SiO2-TiO2/g-C3N4 composite photocatalyst for hydrogen production and pollutant degradation: Insight into the effect of SiO2

Using low-cost precipitated silica (SiO2) as the carrier, a ternary SiO2-TiO2/g-C3N4 composite photocatalyst was prepared via the sol-gel method associated with a wet-grinding process. The as-prepared composite exhibits photocatalytic hydrogen production and pollutant degradation performance under solar-like irradiation. The effect of SiO2 carrier on the properties of the heterostructure between TiO2 and g-C3N4 (CN) was systematically studied. It is found that SiO2 has important effects on promoting the interaction between TiO2 and CN. The particle size of TiO2 and CN was obviously reduced during the calcination process due to the effects of SiO2. Especially, the TiO2 particles exhibit monodispersed state with particle size below 10 nm (quantum dots), resulting in the improvement of the contact area and the interaction between TiO2 and CN, and leading to the formation of efficient TiO2/CN Z-scheme heterostructure in SiO2-TiO2/CN. Besides, the introduction of SiO2 can increase the specific surface area and light absorption of SiO2-TiO2/CN, further promoting the photocatalytic reaction. As expected, the optimum SiO2-TiO2/CN composite exhibits 12.3, 3.1 and 2.9 times higher photocatalytic hydrogen production rate than that of SiO2-TiO2, CN and TiO2/CN under solar-like irradiation, while the photocatalytic active component in SiO2-TiO2/CN is only about 60 wt%. Moreover, the rhodamine B degradation rate of SiO2-TiO2/CN is also higher than that of SiO2-TiO2, CN and TiO2/CN.

Effect of Calcination Temperature on Photocatalytic Activity of Synthesized TiO2 Nanoparticles via Wet Ball Milling Sol-Gel Method

In this work, TiO2 nanoparticles were successfully synthesized with narrow size distribution via a wet ball milling sol-gel method. The effect of calcination temperature on photocatalytic activity was observed from particle size, crystallite size, and phase transition of TiO2 nanoparticles. Increasing calcination temperature increased particle size, crystallite size, and the crystallinity of synthesized TiO2. Phase transition depended on variation in calcination temperatures. A two-phase mixture of anatase and brookite was obtained with lower calcination temperature whereas a three-phase mixture appeared when calcination temperature was 500–600 °C. With higher temperature, the rutile phase kept increasing until it was the only phase observed at 800 °C. Anatase strongly affected the photocatalytic activity from 300 °C to 600 °C while the particle size of TiO2 was found to have a dominant effect on the photocatalytic activity between 600 °C and 700 °C. A mixture of three phases of TiO2-600 exhibited the highest methylene blue degradation with the rate constant of 9.46 × 10−2 h−1 under ultraviolet (UV) irradiation.

Preparation of fluorine and carbon co-introduced TiO2 at low temperature with enhanced visible-light degradation performance for 2,4,6-trichlorophenol

Traditional TiO2 photocatalyst has the disadvantages of weak visible-light responsibility, fast combination of photo-generated electron and hole, which significantly degrade its photocatalytic degradation activity. Therefore, fluorine and carbon co-introduced TiO2 was synthesized at a relatively low calcination temperature via a modified sol-gel method, and then be thoroughly characterized to explore the structure-performance relationship. It was found the optimum catalyst FCT-200 prepared at calcination temperature of 200 °C exhibited remarkably enhanced visible-light absorption and restrained photo-generated carrier combination, which should be attributed to the F, C elements co-introduction, lower crystallization degree, and smaller particle size of anatase TiO2. With such advantages, the catalyst therefore demonstrated satisfactory photocatalytic degradation activity for 2,4,6-trichlorophenol (2,4,6-TCP) under visible-light irradiation. The apparent degradation rate reached as high as 0.41971 h−1, almost 42 folds higher than P25. It is anticipated that the fluorine and carbon co-introduced TiO2 photocatalyst presented in this work could provide a new insight into significantly improving the photocatalytic performance of TiO2.

The Effects of Concentration and Particle Size of TiO2 on the Dielectric Properties of Polyolefin‐Based Microwave Substrates

AbstractFibre‐reinforced polybutadiene/ styrene‐butadiene‐styrene triblock copolymer/ ethylene‐propylene‐diene terpolymer/titanium dioxide (PB/SBS/EPDM/TiO2) composite laminates with superior dielectric properties were fabricated by impregnation and hot pressing. The effects of concentration and particle size of rutile spherical TiO2 on the microwave dielectric properties of the PB/SBS/EPDM/TiO2 composite laminates were investigated at microwave frequency region. Additionally, the mechanical, thermal, and water absorption properties of the laminates were also evaluated. Results indicated that the dielectric properties were obviously improved with the increase of concentration or the decrease of particle size. The laminate filled with 230 nm TiO2 at a filler loading of 70 wt% possessed high dielectric constant (7.03, 10 GHz), low dielectric loss (0.0042, 10 GHz), outstanding mechanical, thermal properties, and low water absorption. Enhanced dielectric properties and other prominent properties enable the fibre‐reinforced polyolefin‐based composite laminates to be a potential candidate for microwave substrate applications.

Energy dispersive X-ray spectroscopy study of compound semiconductor zinc orthotitanate prepared by solid state reaction method

In this work, the compound semiconductor nanoparticles of Zinc Orthotitanate (Zn2TiO4) was prepared by solid state reaction method. Titanium dioxide (TiO2) and Zinc oxide (ZnO) are two of the most versatile semiconductor materials used as the starting material for this purpose. The particle size from the FESEM image was found in the range of 40–180 nm after solid state reaction which is in consistent with the particle size of ZnO and TiO2 grinded individually. The different structural, morphological and optical characterizations of this compound semiconductor Zn2TiO4 is already been reported. Energy dispersive X-ray spectroscopy (EDX) is one of the important techniques to characterize the aforementioned material in terms of its purity and stoichiometriness. But however, there is hardly any work reported in this direction. So in this work detail EDX study was used in order to determine the element composition that present in the sample. The result of EDX study revealed that the synthesized Zn2TiO4 nanoparticles were of high purity, which contains high Zn, Ti and O element composition. The mass percentages Zn, Ti and O closely match with the ideal value of Zn2TiO4 nanocomposite.

Experimental and Prediction Study of Displacement-Rate Effects on Flexural Behaviour in Nano and Micro TiO2 Particles-Epoxy Resin Composites.

Epoxy resin composites with different weight fractions of TiO2 microparticles (1%, 5%, 10%, 15%, 20%) and of TiO2 nanoparticles (0.5%, 1%, 2%, 3%) were prepared. The particle size of the nanoparticles was averaged around 21 nm while the particle size of the micro TiO2 particles was averaged around 0.2 μm. The morphology of the manufactured particulate composites was studied by means of scanning electron microscopy (SEM). The mechanical properties of both nanocomposites (21 nm) and microcomposites (0.2 μm) were investigated and compared through flexural testing. Furthermore, the effect of displacement-rate on the viscoelastic behavior of composite materials was investigated. The flexural tests were carried out at different filler weight fractions and different displacement-rates (0.5, 5, 10, 50 mm/min). The influence of TiO2 micro- and nanoparticles on the mechanical response of the manufactured composites was studied. For micro TiO2 composites, a maximum increase in flexural modulus on the order of 23% was achieved, while, in the nanocomposites, plastification of the epoxy matrix due to the presence of TiO2 nanoparticles was observed. Both behaviors were predicted by the Property Prediction Model (PPM), and a fair agreement between experimental results and theoretical predictions was observed.