Incorporation Of TiO2 Research Articles

Asphalt nanocomposite with titanium dioxide: Mechanical, rheological and photoactivity performance

This article presents the results of research aimed at evaluating the impact of incorporating different percentages of titanium dioxide (TiO2) nanoparticles on the mechanical and rheological properties and photocatalytic efficiency of a conventional asphalt binder. For that, asphalt nanocomposites (asphalt binder + nanomaterial) were produced with different percentages of TiO2 incorporation (3%, 6%, 9%, 12% and 15%). The experimental investigation was conducted based on the performance of tests at high and intermediate temperatures. The effect of nanomaterials on the matrix in relation to several aspects was evaluated, mainly regarding susceptibility to permanent deformation, fatigue damage tolerance, resistance to oxidative aging, apparent viscosity and alteration of the dynamic shear modulus and phase angle. The photocatalytic efficiency was investigated in a continuous flow photoreactor with atmospheric environment polluted by NOx (nitrogen oxides). Results indicate that the incorporation of nano-TiO2 in the asphalt binder improves the mechanical and rheological behavior of the matrix, providing greater resistance to permanent deformation, greater stiffness, greater fatigue damage tolerance at certain stress/strain levels and increased resistance to oxidative aging. In general, it could be concluded that the photocatalytic semiconductor does not compromise the essential mechanical and rheological properties of the asphalt matrix under study, but rather improves them. Performance in the degradation of nitrogen oxides was not very satisfactory compared to cement matrices.

Structurally improved, TiO2-incorporated, CaO-based pellets for thermochemical energy storage in concentrated solar power plants

Calcium looping process (CaL) is a promising thermochemical energy storage technology for the application in the 3rd generation concentrated solar power plants (CSP). Hence, it is necessary to develop the highly efficient CaO-based heat storage composite materials. The structurally improved, CaO-based pellets were prepared via adding cellulose as the pore-forming template. Furthermore, the approach of TiO2 incorporation was adopted aiming to enhance the anti-sintering ability of the structurally improved, CaO-based pellets. It is found that the structurally improved, TiO2-incorporated, CaO-based pellets that containing 25 wt% of TiO2 exhibit the highest CaO carbonation conversion and energy density of 57.5% and 1827.7 kJ/kg after 20 cycles, which are nearly 1.3 times as high as those of the pure Ca(OH)2 pellets. The superiority of the structurally improved, TiO2-incorporated, CaO-based pellets on cyclic heat energy storage/release is more prominent under harsh calcination conditions (950 °C, pure CO2). The evenly distributed CaTiO3 grains, providing structural stability to the CaO-based pellets and also enhancing the anti-sintering ability, are responsible for the improved cyclic energy storage/release performance. Additionally, the desirable compression strength (16.67 ± 1.05 MPa) contributes to strengthen the practicability of structurally improved, TiO2-incorporated, CaO-based pellets applied in the CaL-CSP system.

Tailoring the Effects of Titanium Dioxide (TiO2) and Polyvinyl Alcohol (PVA) in the Separation and Antifouling Performance of Thin-Film Composite Polyvinylidene Fluoride (PVDF) Membrane.

In this study, thin-film composite (TFC) polyvinylidene fluoride (PVDF) membranes were synthesized by coating with titanium dioxide (TiO2)/polyvinyl alcohol (PVA) solution by a dip coating method and cross-linked with glutaraldehyde. Glutaraldehyde (GA) acted as a cross-linking agent to improve the thermal and chemical stability of the thin film coating. The incorporation of TiO2 in the film enhanced the hydrophilicity of the membrane and the rejection of dyes during filtration. The layer of TiO2 nanoparticles on the PVDF membranes have mitigated the fouling effects compared to the plain PVDF membrane. The photocatalytic performance was studied at different TiO2 loading for the photodegradation of dyes (reactive blue (RB) and methyl orange (MO)). The results indicated that the thin film coating of TiO2/PVA enhanced photocatalytic performance and showed good reusability under UV irradiation. This study showed that nearly 78% MO and 47% RB were removed using the TFC membrane. This work provides a new vision in the fabrication of TFC polymeric membranes as an efficient wastewater treatment tool.

Preparation and Properties of Cordierite Ceramics Obtained via a Pouring-Sintering Method

Due to their low thermal expansion coefficient and high-temperature stability and mechanical properties, cordierite (Mg2Al4Si5O18) ceramics have been extensively used as high-temperature filler materials, catalyst carriers, and insulating materials. During the preparation of cordierite ceramics, it is important to ensure an appropriate sintering temperature, holding time, and proper mineralizer to enhance the strength and toughness of the obtained ceramics. In this paper, cordierite ceramics were prepared by a pouring and sintering method using electrically-fused magnesia, alumina powder, and quartz sand powder as the main raw materials, aluminate cement as the binding agent, and TiO2 as the mineralizer. The effects of sintering temperature and holding time on the phase composition of cordierite ceramics were investigated. This study determined that the appropriate sintering temperature range was 1350–1400 °C and the optimal holding time was 4 h–8 h. The effects of TiO2 incorporation on the flexural strength and water adsorption of cordierite ceramics were also studied. The results indicated that the incorporation of TiO2 increased the flexural strength and reduced the water adsorption of cordierite ceramics. The flexural strength of cordierite ceramics increased to 11.99 MPa, and the water adsorption rate decreased to 2.04% when the amount of incorporated TiO2 reached 8%. Scanning electron microscopy (SEM) revealed that the incorporation of TiO2 promoted the formation of cordierite, refined the grains, and played a toughening role.

Two steps enhancement of dual mode (UC and DS) behaviour of Ho3+/Yb3+ and Tm3+/Yb3+ co-doped GdVO4 phosphors: Improvement in spectral and color purity

In the present work, the dual mode (Upconversion and Downshifting) emission behavior of Tm3+/Yb3+ and Ho3+/Yb3+ co-doped GdVO4 phosphors synthesized via high temperature solid state reaction technique have been studied. The pure phase formation has been confirmed by X-rays diffraction (XRD) studies. The crystalline nature has been found to improve on calcining the phosphors at 1473 K and also by incorporation of TiO2. The surface particles’ shape and size have been studied by SEM technique. The vibrational behaviour of the vanadate host has been investigated by Fourier Transform Infrared (FTIR) measurements. The UV–vis absorption spectra show the formation of charge transfer band (CTB) in UV region due to (VO4)3 group. The non-linear upconversion (UC) spectra show intense blue and NIR emission in GdVO4: Tm3+/Yb3+ phosphor on excitation with 980 nm radiation, whereas intense green and red UC emissions are observed in GdVO4: Ho3+/Yb3+ phosphor. The downshifting (DS) behaviour has been investigated in both the phosphors which show the self activation behaviour of GdVO4 host along with some sharp peaks in blue and green regions due to f-f transitions in Tm3+ and Ho3+ ions. The dual mode (UC and DS) emission has been further improved on heating the samples at higher temperatures and also by incorporation of TiO2. The color of the phosphor samples in the UC emission spectra has been visualized by CIE diagram. The color purity enhances in both the phosphors by increasing the calcination temperature and also by addition of TiO2. The spectral purity has been also calculated for the UC emission spectra and its also shows the same trend. Such phosphors are applicable for the display devices in blue, green and red regions via dual mode processes.

Ethylene scavenging properties from hydroxypropyl methylcellulose-TiO2 and gelatin-TiO2 nanocomposites on polyethylene supports for fruit application

Several technologies have been proposed to preserve fruits and to avoid postharvest losses. The degradation of ethylene produced by the fruits using TiO2 photocatalysis has shown to be a good option to delay the ripening of fruits. This paper proposed a new application of biopolymers-TiO2 nanocomposites developed to extend the shelf-life of fruits. Photocatalytic coatings were applied on the expanded polyethylene foam nets to degrade ethylene. Gelatin and hydroxypropyl methylcellulose (HMPC) were tested as hydrophobic and hydrophilic matrices for the TiO2 incorporation. First, nanocomposite films prepared by casting were evaluated with regards to their photocatalytic properties. Both matrices, which were loaded with 1 wt% TiO2, degraded 40% of the ethylene injected in a batch reactor. By Langmuir-Hinshelwood model, ethylene degradation using gelatin-TiO2 films (kapp = 0.186 ± 0.021 min−1) was faster than the HPMC-TiO2 films (kapp = 0.034 ± 0.003 min−1). Then, gelatin-TiO2 dispersion was applied as a coating on the foam nets by dip coating. The gelatin-TiO2 bilayer exhibited higher concentration of ethylene degraded per photocatalytic area and photocatalyst mass unit (13.297 ± 0.178 ppmv m2gTiO2−1) than its film form (18.212 ± 1.157 ppmv m2gTiO2−1), which makes gelatin-TiO2/foam nets a promising composite design for fruit postharvest application.

Physical and Barrier Properties of Polylactic Acid/Halloysite Nanotubes-Titanium Dioxide Nanocomposites

In this study, PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites films were fabricated via solution casting method. By testing the film density, solubility, water contact angle and water vapor permeability, the PLA nanocomposite films, the comprehensive performances of the nanocomposites were analysed. The outcomes demonstrated that maximum film density of PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites films increased gradually with the increasing of nanofiller loadings. Moreover, the incorporation of TiO2 and HNTs-TiO2 significantly decreased the water vapor transmittance rate of the nanocomposite films with a slight priority to the addition of HNTs-TiO2, the water solubility was significantly improved with the addition of both nanofillers. Furthermore, the barrier properties were developed with the addition of both TiO2 and HNTs-TiO2 especially after the addition of low nanofiller loadings. Overall, the performance of the PLA/HNTs-TiO2 nanocomposite films was better than that PLA/TiO2 film. Nevertheless, both of the PLA nanocomposite samples achieved the requests of food packaging applications.

Preparation and characterization of photocatalytic PSf-TiO2/GO nanohybrid membrane for the degradation of organic contaminants in natural rubber wastewater

Although the improvement of photocatalytic property has been reported to be a promising strategy to enhance the anti-fouling of the membranes, the inclusion of a single photocatalytic material into membrane matrix still exhibits low organic foulants degradation capacity. In this study, two photoactive materials, i.e. nano-TiO2 and graphene oxide (GO) are selected as fillers in the fabrication of polysulfone (PSf) membranes. A thorough investigation was devoted to the photocatalytic activity of the membrane for the degradation of organic pollutants in natural rubber wastewater under dark environment and static UV light irradiation. In order to search the best TiO2 and GO composition, early data curation based on membrane permeability and selectivity was carried out. Membrane with TiO2 loading at 1.5 wt% demonstrated its best performance by providing permeate flux of 16.29 L m−2 h−1 with organic removal up to 79.27%. On the other hand, the membrane loaded with 1.0 wt% GO only exhibited permeate flux up to 8.15 L m−2 h−1 with organic removal up to 70.73%. Upon the incorporation of TiO2/GO mixture as filler materials to the PSf membrane, remarkable results were achieved, which consists of permeate flux, organic and ammonia removals of 13.05 L m−2 h−1, 60.98% and 91.27%, respectively. Based on batch photocatalytic activity assessment, the PSf-TiO2/GO membrane showed the fastest photodegradation reaction. The results proved that the incorporation of TiO2 and GO nano particle as photoactive materials to the PSf membrane matrix results in a synergistic effect in improving photocatalytic capacity and stability of the membrane.

Effect of Surfactants’ Tail Number on the PVDF/GO/TiO2-Based Nanofiltration Membrane for Dye Rejection and Antifouling Performance Improvement

In this work, the novel utilisation of customised double- and triple-tail sodium bis(3,5,5-trimethyl-1-hexyl) sulphosuccinate (AOT4) and sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-silphonate (TC14) surfactants to assist the direct graphene oxide (GO) synthesis via electrochemical exfoliation utilising dimethylacetamide (DMAc) as a solvent were investigated. The synthesised DMAc-based GO and titanium dioxide (TiO2) nanoparticles were then used to fabricate polyvinylidene fluoride (PVDF)-based nanofiltration (NF) membranes by the non-solvent-induced phase separation method. The incorporation of GO and TiO2 as hydrophilic nanoparticles were to enhance membrane hydrophilicity. The utilisation of higher surfactants’ tail number obviously alters the fabricated membrane’s morphology which further affects its performance for dye rejection and antifouling ability. Higher surfactants’ tail number resulted in higher oxidation process which then provided more interaction between the GO and PVDF. Based on the dead-end cell measurement, PVDF/TC14-GO/TiO2 presented a slightly higher dye rejection efficiency of 92.61% as compared to PVDF/AOT4-GO/TiO2 membrane (92.39%). However, PVDF/TC14-GO/TiO2 possessed three times higher water permeability (48.968 L/m2 h MPa) than PVDF/AOT4-GO/TiO2 (16.533 L/m2 h MPa) and also higher hydrophilicity as presented by lower contact angle (65.4 ± 0.17°). This confirmed that higher surfactants’ tail number improved the fabricated membrane’s performance. Both fabricated membranes also exhibited high flux recovery ratio (FRR) ( $$>$$ 100%) which indicated better antifouling properties.

Processing and characterization of TiO2 filled polymer composites

This paper reports on the research dealing with the processing and characterization of TiO 2 filled polymer composites. It also presents the test results in regard to the physical, mechanical and micro-structural characteristics of the epoxy and polypropylene composites filled with micro-sized TiO 2 particles. The effective thermal conductivity of polymer composites with uniformly distributed micro-sized particulates are estimated using a theoretical heat conduction model proposed previously by the authors and the correlation is validated for TiO 2 filled polymers through numerical analysis and experimentation. Some other important thermal characteristics, such as glass transition temperature (T g ) and coefficient of thermal expansion (CTE) of epoxy and polypropylene composites are also estimated. The effects of TiO 2 content on these properties of epoxy and polypropylene have been studied experimentally. The estimation of effective thermal conductivity of the composites using finite element method (FEM) and the proposed theoretical model is done and the results are validated by corresponding experimental results. The findings of this research suggest that incorporation of TiO 2 into epoxy and polypropylene leads to substantial improvement in thermal conductivity and glass transition temperature of the resins. At the same time, TiO 2 helps in lowering the coefficient of thermal expansion of such composites. This work further shows that the FEM serves as a good predictive tool for assessment of thermal conductivity of these composites. The theoretical correlation proposed in this work can serve as a very good empirical model for spherical inclusions to estimate the effective thermal conductivity of the composites within the percolation limit. With light weight and improved heat conduction capability, the TiO 2 filled polymer composites can be used for applications such as electronic packaging, encapsulations, communication devices, thermal interface material, printed circuit board substrates etc.

The color stability of maxillofacial silicones: A systematic review and meta analysis.

Aim:This systematic review aims to identify and interpret results of studies that evaluated the changes in the color stability of maxillofacial prosthetic materials due to chemical instability of silicones and pigments and the effect of exposure to environmental conditions and aging factors on the same.Settings and Design:This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines (PRISMA).Materials and Methods:Relevant articles written in English only, before November 15, 2019, were identified using an electronic search in the PubMed/Medline conducted to identify pertinent articles. The relevancy of the articles was verified by screening the title, abstract, and full text, if they met the inclusion criteria. A total of 42 articles satisfied the criteria, from which data were extracted for qualitative synthesis. This review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO registration number CRD42019124562).Statistical Analysis Used:Since considerable data heterogenicity was present in all studies except the ones on incorporation of TiO2 for which meta-analysis using random effects model was performed.Results:The database search resulted in 234 studies, of which 202 articles were excluded due to lack of relevance, duplication, and unavailability of data. The remaining 32 fulltext articles were assessed for eligibility, out of which 2 articles were excluded. Twelve articles were yielded by manual search. A total of 42 studies were included in the present systematic review. Due to heterogeneous data, meta-analysis could be only carried out with the effect of TiO2 nano particle on color stability.Conclusions:Although there has been extensive amount of research in this field, an ideal maxillofacial silicone exhibiting good color stability in various human and environmental aging conditions is yet to be identified. Human and environmental aging conditions have an adverse effect on the color stability and addition of TiO2 nano particle seems to improve the same.

Synthesis and Characterization of Montmorillonite-Supported Tio2 Composites for Enhanced UV Absorption

AbstractTitanium dioxide (TiO2, rutile) nanoparticles, inorganic ultraviolet absorbers, are used extensively in sunscreen cosmetics as an inorganic ultraviolet (UV) absorber to prevent skin damage; because of their nanotoxicity, use in combination with a support, such as montmorillonite (Mnt), rather than alone, is suggested. Mnt-supported TiO2 composites (Mnt-TiO2) for sunscreens are most suitable when the particles are spherical and of relatively uniform size, which are normally accomplished by spray drying, but this is difficult to achieve because of the naturally layered structure of Mnt. The objective of the present study was, therefore, to find the ideal characteristics of spray-drying nozzles to produce the desired spherical shape and size distribution of the Mnt-TiO2 composite particles. The starting Mnt was extracted from natural bentonite by particle-size separation. An ultrasonic nozzle in the spray dryer was selected for use in the synthesis of Mnt-TiO2 composites based on the particle-size distribution (PSD) of Mnt prepared using a two-fluid nozzle and an ultrasonic nozzle at 453 K. The incorporation of TiO2 in the final Mnt-TiO2 composites was examined by X-ray powder diffraction (XRD) and elemental analysis. With increasing TiO2 concentration, the TiO2 content and average particle size of the Mnt-TiO2 composites increased. Scanning electron microscopy (SEM) images showed that all samples prepared had uniform and nearly spherical shapes. Absorbance of UV by Mnt-TiO2 (5:1) composites was greater than that by either purified Mnts or pure TiO2. The present study demonstrated a simple method, using a spray dryer with an ultrasonic nozzle, to synthesize Mnt-TiO2 composites of uniform size and shape suitable for cosmetic application.

Facile refluxed synthesis of TiO2/Ag2O@Ti-BTC as efficient catalyst for photodegradation of methylene blue and electrochemical studies

Due to unique properties, metal organic frameworks (MOFs) have attracted great research attention towards sustainable energy and environmental remediation. In this article, highly efficient TiO2@Ti(BTC) and TiO2/Ag2O@Ti(BTC) composites have been synthesized via in-situ incorporation of pre-synthesized TiO2 and TiO2/Ag2O into Ti-based MOF Ti(BTC) via facile refluxed method. All the synthesized samples have been successfully characterized by PXRD, SEM, EDX and UV-Visible spectroscopy. All these samples are used for study the photodegradation of methylene blue in aqueous solution under visible light irradiation. It has been found that incorporation of TiO2 NPs and TiO2/Ag2O nanocomposite into Ti(BTC) shifts the band gap towards more visible region, elevates the yield of O 2 ∙– and OH∙– radicals and enhances the photodegradation efficiency of methylene blue in the presence of visible light. Amongst all the synthesized samples, TiO2/Ag2O@Ti(BTC) shows maximum photocatalytic activity towards photodegradation of methylene blue as compared to all other synthesized samples. It is observed that after 60 min, TiO2/Ag2O@Ti(BTC) shows minimum absorption of 0.02 as compared to TiO2 (0.17), TiO2/Ag2O (0.052), Ti(BTC) (0.32) and TiO2@Ti(BTC) (0.21). It reveals that methylene blue has been successfully degraded by synthesized samples and maximum activity has been shown by TiO2/Ag2O@Ti(BTC). Further, electrochemical water splitting activity of these samples has been studied. It has been found that TiO2/Ag2O@Ti(BTC) shows maximum catalytic activity towards both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). It generates maximum current density 97.15 and − 110 mA cm−2 towards both OER and HER, respectively, as compared to all other samples.

Rheological Analysis of Asphalt Binders Modified with Hydrated Lime and Titanium Dioxide Nanoparticles

The significant increase in traffic on paved roads has accelerated the deterioration of asphalt coatings. Because of this, the use of additives to modify the properties of the asphalt binder has been studied in order to improve the performance in relation to, mainly, permanent deformations and fatigue life. This work evaluates the changes in the rheological properties of CAP 50/70 modified with fractionated particles of hydrated lime and titanium dioxide nanoparticles, obtained from the use of a ball mill. For this purpose, the CAP 50/70 was modified with the addition of fractionated lime particles in the contents of 3%, 5% and 7% by weight of the pure binder and with 3% of ground nano TiO2 (180 nm). The modified samples showed less loss of mass in the short term aging, proving to be an antioxidant alternative. In addition, it was found that the modified binders provided an increase in G* (stiffness parameter) and, consequently, in the maximum Performance Grade (PG) temperature, allowing the use of the studied binders at higher temperatures. The binder modified with a content of 5% hydrated lime presented better results in the tests of permanent deformation (MSCR and LAS). The decrease in TiO2 granulometry increased the integrity of the binder and made it more sensitive to deformations under temperature variations, however, milled titanium dioxide showed a positive result in increasing the resistance of the asphalt binder to fatigue when compared to the binder with nano TiO2 220 nm. Finally, it was possible to establish that the addition of fractionated particles of hydrated lime to CAP 50/70 is a viable and effective technique that meets the requirements of DNIT for use in paving and that the incorporation of ground nano TiO2 (180 nm) attributed to the asphalt binder 50/70 higher working temperature in the field.

Studies on the formation and hydration of tricalcium silicate doped with CaF2 and TiO2

The comprehensive utilization of wasted pickling sludge in the cement kiln would be a promising practice, but the calcination process of cement clinker became complicated due to the simultaneous introduction of titanium and fluorine. In this paper, the formation and hydration of tricalcium silicate (C3S) doped with CaF2 and TiO2 were discerned by XRD, FT-IR, XPS and isothermal calorimetry. The results revealed that the addition of CaF2 more than 1.5% would promote the appearance of CaTiO3 as the indicator of the solution limit of TiO2, and the formation of CaTiO3 and β-C2S was a concomitant process as the solution limit of TiO2 reached. The addition of 0.5% TiO2 and some addition of CaF2 (≤1.5%) would reduce the polymorph symmetry of C3S, while more addition of CaF2 and TiO2 would actualize the higher polymorph symmetry from M1 to R form. The IR spectra for the polymorphs (T3, M3, R + M3, R) became broader with the increase of the polymorph symmetry of C3S. The replacement of O2− by F− would not be interfered by the simultaneous introduction of titanium, a Ti2p 1/2 peak at 463.39 eV reflected the solution of titanium in the structure of C3S, and the defect reactions of the doped C3S with CaF2 and TiO2 were proposed. The doped C3S had a higher heat flow than the undoped C3S in the initial period, the more addition of CaF2 inhibited the initial hydration activity of C3S, while the addition of TiO2 improved the effect. The incorporation of TiO2 into the doped C3S aggravated the retardation effect caused by CaF2 on the hydration in the acceleration period. The dopant types displayed a more distinct effect than the types of C3S polymorphs on the hydration activity of C3S.

Production of TiO2-deposited Diatoms and Their Applications for Photo-catalytic Degradation of Aqueous Pollutants

Biogenic TiO2 diatoms can be prepared by metabolic incorporation of TiO2 on the frustule surface of the diatoms. To utilize the photo-catalytic activity of biogenic TiO2 for practical applications, high production of TiO2-deposited diatoms is required. Here, we evaluated the growth rate and biogenic TiO2 production of several domestic diatom species. Among the tested diatoms, Caloneis schroederi (CS) showed high biomass production (4.01 g/L) in a two-stage cultivation system and proper exoskeletal rigidity for efficient production of biogenic TiO2. The dry weight of the TiO2-deposited CS frustules (biogenic CS-TiO2) was 4.52 g/L. Biogenic CS-TiO2 showed significant photo-catalytic degradation of Congo Red in water with an efficiency of 27.8%, which is higher than that of standard TiO2 (17.4%). In addition, chloroform could be removed from water through the photo-catalytic activity of biogenic CS-TiO2 (91%). Therefore, the biogenic CS-TiO2 developed in this study can be employed for the treatment of pollutant-contaminated wastewater.

Comparative study of behavior of electrical conductivity in KI‒Al2O3 and KI‒TiO2 heterostructure composites

The present work reports development of binary KI–Al2O3 and KI–TiO2-based nanocomposites using simple solid-state reaction method and is characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy and impedance spectroscopy. The results show the effect of heterogeneously doped Al2O3 and TiO2 on the ionic conductivity of pure KI which is moderately conductive. The results supported the composite development in which the interface layer portrays a significant part in governing the bulk properties of the compound. Improvement in electrical conductivity is seen in the incorporation of Al2O3 and TiO2 dispersoid into the matrix of KI. With temperature, electrical conductivity increased and the activation energies were found to be decreasing. The activation energies for KI–Al2O3 and KI–TiO2 systems were 0.22 eV and 0.21 eV, respectively, in the temperature range 20‒400 °C. Dielectric constant increases with the increase in temperature in the entire temperature range studied attributed to the phenomenon of distortion of electric charges.

Study on Biodegradable Chitosan-Whey Protein-Based Film Containing Bionanocomposite TiO2 and Zataria multiflora Essential Oil

In our research, a composite film of whey protein isolate (WPI)/chitosan incorporated with TiO2 nanoparticles (NPs) and essential oil of Zataria multiflora (ZEO) was developed. The resulting composite films were evaluated by FTIR, SEM, and XRD, and also the physicochemical characteristics including color, mechanical properties, swelling ratio, and water vapor permeability (WVP) were studied. SEM graphs exhibited that the samples had a uniform and homogeneous structure where TiO2 NPs and ZEO were well dispersed. FTIR and XRD findings also show that the hydrogen bonds and hydrophobic interactions are the main interactions between the composite WPI/chitosan and TiO2. The crystalline nature of the composite samples increased with the increase of NP content. Nevertheless, ZEO had an insignificant effect on the functional groups and the crystallinity of composite samples. The film visual characterization revealed that, by adding and increasing the TiO2 and TiO2-ZEO, sample lightness and opacity significantly increased. Additions of TiO2 remarkably (p<0.05) improved the water vapor and mechanical properties of composite samples, although the loading of ZEO, regardless of TiO2 incorporation, led to a considerable decrement of these properties. Furthermore, composite films containing ZEO combined with 2% of TiO2 compared with 1% of NPs blended with ZEO had strong antimicrobial properties against Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes. Generally, the findings proposed that the addition of TiO2 reinforces the properties of composite films with a synergistic effect of ZEO loading on the antibacterial ability, by which the resulting biodegradable composite samples can be used as a food active packaging material.

Photocatalytic degradation of metoprolol in aqueous medium using a TiO2/natural zeolite composite

Photodegradation of metoprolol using a TiO2 and Mexican natural zeolite composite (T/MZ) was studied. The photocatalyst was successfully synthesized by physical mixing method where commercial TiO2 Degusa P25 was supported on thermochemical modified clinoptilolite. X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy confirmed the TiO2 incorporation over the clinoptilolite surface without structural changes of the zeolite. Point of zero charge of 6.2 was found for the T/MZ, while the bandgap energy of 3.15 eV was obtained by UV–Vis diffuse reflectance spectroscopy. Photodegradation tests of metoprolol as a model emerging pollutant were carried out, finding that the T/MZ composite to have superior degradation percentages thant the commercial TiO2 P25 for all the pH values tested (3–9), which demonstrates a synergistic effect between the semiconductor material and the zeolitic support. Finally, it was found that the kinetics degradation of metoprolol follows the Langmuir, Hinshelwood, Hougen and Watson (LHHW) model.

Sorption, solubility and cytotoxicity of novel antibacterial nanofilled dental adhesive resins

Dental adhesives hydrolyze in the mouth. This study investigated the water sorption (SOR), solubility (SOL) and cytotoxicity (CYTO) of experimental adhesives containing nitrogen-doped titanium dioxide nanoparticles (N_TiO2). Specimens (n = 15/group [SOR, SOL]; n = 10/group [CYTO]) of unaltered Clearfil SE Protect (CSP), OptiBond Solo Plus (OSP), Adper Scotchbond (ASB) and experimental adhesives (OSP + 25% or 30% of N_TiO2) were fabricated, desiccated (37 °C) and tested for SOR and SOL according to ISO Specification 4049 (2009). CYTO specimens were UV-sterilized (8 J/cm2) and monomer extracted in growth medium (1, 3 or 7 days). Human pulp cells were isolated and seeded (0.5 × 104) for MTT assay. SOR and SOL data was analyzed using GLM and SNK (α = 0.05) and CYTO data was analyzed with Kruskal–Wallis and SNK tests (α = 0.05). SOR and SOL values ranged from 25.80 μg/mm3 (30% N_TiO2) to 28.01 μg/mm3 (OSP) and 23.88 μg/mm3 (30% N_TiO2) to 25.39 μg/mm3 (25% N_TiO2). CYTO results indicated that pulp cells exposed to experimental materials displayed comparable viabilities (p > 0.05) to those of OSP. Experimental materials displayed comparable SOR, SOL and CYTO values (p > 0.05) when compared to unaltered materials. N_TiO2 incorporation have not adversely impacted SOR, SOL and CYTO properties of unaltered adhesives.