The use of titanium dioxide nanoparticles (nTiO<sub>2</sub>) is gaining interest in agriculture because of their impact on many aspects of plant growth. The present study examines the effects of nTiO<su...The use of titanium dioxide nanoparticles (nTiO<sub>2</sub>) is gaining interest in agriculture because of their impact on many aspects of plant growth. The present study examines the effects of nTiO<sub>2</sub> (5 nm and 10 nm) applied to seeds and the seedlings as a foliar application on various aspects of growth characteristics and biomass accumulation in lettuce (Lactuca sativa, cv. Grand Rapids). Application of 10 nm nTiO<sub>2</sub> to seeds through imbibition resulted in a significant reduction in shoot biomass accumulation while 5 nm nTiO<sub>2</sub> did not affect the biomass accumulation in lettuce. The application of 10 nm nTiO<sub>2</sub> reduced the fresh shoot biomass accumulation by about 18% compared to the control plants. Other growth characteristics such as shoot dry biomass, root fresh and dry biomass, plant height, and leaf area were not affected by the application of both 5 nm and 10 nm nTiO<sub>2</sub>. In addition, foliar application of these nanoparticles to the lettuce seedlings did not have a significant effect on most of the growth parameters examined, and the increasing concentration ranging from 5 nm/L to 400 mg/L did not produce a consistent response in lettuce. Thus, nTiO<sub>2</sub> application to lettuce seeds had a notable negative impact on shoot growth while foliar application did not have a significant effect on many plant growth characteristics. However, foliar applications produced some symptoms of toxicity to the foliage in the form of necrotic or chlorotic patches on the leaves, which were more pronounced with increasing concentrations of both 5 nm and 10 nm nTiO<sub>2</sub>. However, these symptoms were apparent at a concentration as low as 50 mg/L of nTiO<sub>2</sub>. Thus, foliar application of nTiO<sub>2</sub> may not have a significant impact on many of the growth characteristics in lettuce, but it can result in foliar toxicity.展开更多
In this study,three-dimensional porous magnesium ferrite/titanium dioxide/reduced graphene oxide(Mg Fe_2O_(4)-GM/TiO_(2)/rGO(MGTG))was successfully synthesized via green and hydrothermal-supported co-precipitation met...In this study,three-dimensional porous magnesium ferrite/titanium dioxide/reduced graphene oxide(Mg Fe_2O_(4)-GM/TiO_(2)/rGO(MGTG))was successfully synthesized via green and hydrothermal-supported co-precipitation methods using the extract of Garcinia mangostana(G.mangostana)as a reducing agent.The characterization results indicate the successful formation of the nano/micro Mg Fe_(2)O_(4)(MFO)and TiO_(2) on the structure of the reduced graphene oxide(rGO),which can also act as efficient support,alleviating the agglomeration of the nano/micro MFO and TiO_(2).The synergic effects of the adsorption and photodegradation activity of the material were investigated according to the removal of crystal violet(CV)under ultraviolet light.The effects of catalyst dosage,CV concentration,and p H on the CV removal efficiency of the MGTG were also investigated.According to the results,the CV photodegradation of the MGTG-200 corresponded to the pseudo-first-order kinetic model.The reusability of the material after 10 cycles also showed a removal efficiency of 92%.This happened because the materials can easily be recollected using external magnets.In addition,according to the effects of different free radicals·O_(2)^(-),h^(+),and·OH on the photodegradation process,the photocatalysis mechanism of the MGTG was also thoroughly suggested.The antibacterial efficiency of the MGTG was also evaluated according to the inhibition of the Gram-positive bacteria strain Staphylococcus aureus(S.aureus).Concurrently,the antibacterial mechanism of the fabricated material was also proposed.These results confirm that the prepared material can be potentially employed in a wide range of applications,including wastewater treatment and antibacterial activity.展开更多
To meet the low-cost concept advocated by the sodium metal anode,this paper reports the use of a pulsed electrodeposition technology with ionic liquids as electrolytes to achieve uniform nanoplating of metallic magnes...To meet the low-cost concept advocated by the sodium metal anode,this paper reports the use of a pulsed electrodeposition technology with ionic liquids as electrolytes to achieve uniform nanoplating of metallic magnesium films at around 20 nm on spaced titanium dioxide(TiO_(2))nanotubes(STNA-Mg).First,the sodiophilic magnesium metal coating can effectively reduce the nucleation overpotential of sodium metal.Moreover,three-dimensional STNA can limit the volume expansion during sodium metal plating and stripping to achieve the ultrastable deposition and stripping of sodium metals with a high Coulombic efficiency of up to 99.5%and a small voltage polarization of 5 mV in symmetric Na||Na batteries.In addition,the comparative study of sodium metal deposition behavior of STNA-Mg and STNA-Cu prepared by the same route further confirmed the advantage of magnesium metal to guide sodium metal growth.Finally,the prepared STNA-Mg-Na metal anode and commercial sodium vanadium phosphate cathode were assembled into a full cell,delivering a discharge capacity of 110.2 mAh·g^(-1)with a retention rate of 95.6%after 110 cycles at 1C rate.展开更多
Extremely high-temperature and high-pressure requirement of Haber-Bosch process motivates the search for a sustainable ammonia synthesis approach under mild conditions.Photocatalytic technology is a potential solution...Extremely high-temperature and high-pressure requirement of Haber-Bosch process motivates the search for a sustainable ammonia synthesis approach under mild conditions.Photocatalytic technology is a potential solution to convert N2 to ammonia.However,the poor light absorption and low charge carrier separation efficiency in conventional semiconductors are bottlenecks for the application of this technology.Herein,a facile synthesis of anatase TiO_(2)nanosheets with an abundance of surface oxygen vacancies(TiO_(2)-OV)via the calcination treatment was reported.Photocatalytic experiments of the prepared anatase TiO_(2)samples showed that TiO_(2)-OV nanosheets exhibited remarkably increased ammonia yield for solar-driven N2 fixation in pure water,without adding any sacrificial agents.EPR,XPS,XRD,UV-Vis DRS,TEM,Raman,and PL techniques were employed to systematically explore the possible enhanced mechanism.Studies revealed that the introduced surface oxygen vacancies significantly extended the light absorption capability in the visible region,decreased the adsorption and activation barriers of inert N2,and improved the separation and transfer efficiency of the photogenerated electronhole pairs.Thus,a high rate of ammonia evolution in TiO_(2)-OV was realized.This work offers a promising and sustainable approach for the efficient artificial photosynthesis of ammonia.展开更多
Titanium dioxide Nanotubes(TNTs) prepared by electroless deposition have been annealed at air ambient and low temperature. As a result, the anatase/rutile phase composition of the TNTs can be tailored to the needs of ...Titanium dioxide Nanotubes(TNTs) prepared by electroless deposition have been annealed at air ambient and low temperature. As a result, the anatase/rutile phase composition of the TNTs can be tailored to the needs of later applications. Nanotubes with anatase/rutile mixed phase ratio of 4:1 have been produced in this report and further examined for their photocatalytical behavior. The photocatalytical properties of the TNTs have been observed by degradation of methylene-blue in aqueous solution under low power UV-light irradiation. The results shown in this report are based on the synergetic effect between rutile and anatase,which results in the mixed phase TiO 2 nanotubes having enhanced photocatalytical properties.展开更多
The novel sulfonated polybenzimidazole(sPBI)/amine functionalized titanium dioxide(AFT) composite membrane is devised and studied for its capability of the application of high temperature proton exchange membrane fuel...The novel sulfonated polybenzimidazole(sPBI)/amine functionalized titanium dioxide(AFT) composite membrane is devised and studied for its capability of the application of high temperature proton exchange membrane fuel cells(HT-PEMFCs),unlike the prior low temperature AFT endeavors.The high temperature compatibility was actualized because of the filling of free volumes in the rigid aromatic matrix of the composite with AFT nanoparticles which inhibited segmental motions of the chains and improved its thermal stability.Besides,amine functionalization of TiO2 enhanced their dispersion character in the sPBI matrix and shortened the interparticle separation gap which finally improved the proton transfer after establishing interconnected pathways and breeding more phosphoric acid(PA) doping.In addition,the appeared assembled clusters of AFT flourished a superior mechanical stability.Thus,the optimized sPBI/AFT(10 wt%) showed 65.3 MPa tensile strength;0.084 S·cm^-1 proton conductivity(at 160℃;in anhydrous conditions),28.6% water uptake and PA doping level of 23 mol per sPBI repeat unit.The maximum power density peak for sPBI/AFT-10 met the figure of0.42 W·cm^-2 at 160℃(in dry conditions) under atmospheric pressure with 1.5 and 2.5 stoichiometric flow rates of H2/air.These results affirmed the probable fitting of sPBI/AFT composite for HT-PEMFC applications.展开更多
Titanium dioxide(Ti O_(2))nanopowder(P-25;Degussa AG)was treated using dielectric barrier discharge(DBD)in a rotary electrode DBD(RE-DBD)reactor.Its electrical and optical characteristics were investigated during RE-D...Titanium dioxide(Ti O_(2))nanopowder(P-25;Degussa AG)was treated using dielectric barrier discharge(DBD)in a rotary electrode DBD(RE-DBD)reactor.Its electrical and optical characteristics were investigated during RE-DBD generation.The treated TiO_(2)nanopowder properties and structures were analyzed using x-ray diffraction(XRD)and Fourier-transform infrared spectroscopy(FTIR).After RE-DBD treatment,XRD measurements indicated that the anatase peak theta positions shifted from 25.3°to 25.1°,which can be attributed to the substitution of new functional groups in the TiO_(2)lattice.The FTIR results show that hydroxyl groups(OH)at 3400 cm-1 increased considerably.The mechanism used to modify the TiO_(2)nanopowder surface by air DBD treatment was confirmed from optical emission spectrum measurements.Reactive species,such as OH radical,ozone and atomic oxygen can play key roles in hydroxyl formation on the TiO_(2)nanopowder surface.展开更多
Titanium dioxide nanotubes(TNTs)were prepared by electroless deposition using ion track etched polycarbonate templates.The ion tracks were prepared to the desired diameter of the TNTs outer diameter.Titanium dioxide n...Titanium dioxide nanotubes(TNTs)were prepared by electroless deposition using ion track etched polycarbonate templates.The ion tracks were prepared to the desired diameter of the TNTs outer diameter.Titanium dioxide nanotubes with a diameter of minimum 80 nm having a wall thickness of minimum 10 nm can be fabricated using this method.To achieve nanotubes with thin walls and small surface roughness the tubes were generated by a several steps procedure under aqueous conditions at nearly room temperature.The presented approach will process open end nanotubes with well defined outer diameter and wall thickness.Using this method TNT arrays up to 109 tubes per cm2having a tube length up to 30μm can be produced,single tubes are also possible.The structural properties of the grown TNTs were investigated by using various analytical techniques,i.e.scanning electron microscopy(SEM),energy dispersive X-ray fluoresence spectrometer(EDX),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),Raman spectroscopy and Photoluminescence.展开更多
At present,a growing number of consumer products contain engineered nanoparticle TiO2(nano⁃TiO2),which has resulted in the consequences of nano⁃TiO2 entering the aquatic environment directly or indirectly at some stag...At present,a growing number of consumer products contain engineered nanoparticle TiO2(nano⁃TiO2),which has resulted in the consequences of nano⁃TiO2 entering the aquatic environment directly or indirectly at some stage.The fate of nano⁃TiO2 in the aquatic environment has become the key factor which affects its safety application and nanoecotoxicology.This paper aims to investigate how the dissolved organic matters(DOM),especially the molecular weight fractions in the aquatic environment,affect the aggregation,stability,and fate of nano⁃TiO2,and the interaction mechanism of DOM and nano⁃TiO2.Results of dynamic light scattering(DLS)showed that the molecular weight of DOM molecules caused different aggregation rates of nano⁃TiO2 in aqueous solution.Fourier Transform infrared spectroscopy(FTIR)results indicated the molecular structure is characteristics of DOM fractions and the mechanisms of bonds formation between DOM and nano⁃TiO2.Results of three⁃dimensional excitation⁃emission matrices(3D⁃EEM)confirmed the FTIR results and implied the increase of the stability of theπ-πconjugated system in the presence of DOM.In addition,low molecular weight of DOM fractions appeared to show more affinity with nano⁃TiO2 than high molecular weight fractions.展开更多
Titanium is a very important element for several industrial applications, being one of the ninth most abundant elements in the Earth’s crust (0.63% wt). In this work it will discuss the different mining and industria...Titanium is a very important element for several industrial applications, being one of the ninth most abundant elements in the Earth’s crust (0.63% wt). In this work it will discuss the different mining and industrial activities involved in the production of titanium dioxide. The first step analyzed will treat about the beneficiation mining process of titanium mineral, and secondly, it will discuss the two main processes of the TiO2 manufacturing (sulphate and chloride routes). In addition, we will show different uses of the titanium dioxide pigment as filler in paper, plastics and rubber industries and as flux in glass manufacture, etc. Finally, we will show that the old wastes are currently called co-products since they were valorized, being commercialized by the Spanish industry of TiO2 production in different fields such as agriculture, civil engineering, or cement manufacturing.展开更多
The performance of local clay-titanium dioxide core-shell extender pigments in alkyd paints has been studied. The physico-mechanical properties of the prepared alkyd paints were evaluated according to ASTM measurement...The performance of local clay-titanium dioxide core-shell extender pigments in alkyd paints has been studied. The physico-mechanical properties of the prepared alkyd paints were evaluated according to ASTM measurements. The effects of various environmental and corrosive factors on the paints were also studied. The study showed that the alkyd paint samples formulated using the core-shell pigments generally had low specific gravity (1.30 – 1.38), an indication that more of the core-shell pigments can be incorporated into the alkyd paints with considerable cost savings. The dry film thicknesses of the paint samples falls within 0.24 - 0.39 mm, suggesting that the samples will perform well as anticorrosive coatings and their adhesion properties are generally good, showing that they can withstand abrasive and corrosive agents. The core-shell extender pigments formulated paint samples were observed to exhibit the best dust-free, tack-free, and through dry times compared to TiO<sub>2</sub> paint formulation. The formulated paint samples generally performed well on exposure to rain and sunlight as well as in distilled water, 2% Na<sub>2</sub>CO<sub>3</sub>, and 2% H<sub>2</sub>SO<sub>4</sub> with only TiO<sub>2</sub> paint formulation exhibiting rust. The good paint performance characteristics obtainable with the core-shell extender pigments are enough evidence to justify their utilization in the surface coatings industry. The performances of these core-shell extender pigments in alkyd paints have shown that they combine the properties of both the clays and titanium dioxide, and have the potential to overcome their disadvantages.展开更多
In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs t...In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs to be better understood. Nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoric acid solution during 20 minutes and then annealed in air atmosphere. In-situ X-ray diffraction analysis, coupled with thermogravimetry, gives us an inside on the oxidation behaviour of titanium dioxide nanotube layers compared to bulk reference samples. Structural studies were performed at 700°C for 12 h in order to follow the time consequences on the oxidation of the material, in sufficient stability conditions. In-situ XRD brought to light that the amorphous oxide layer induced by anodization is responsible for the simultaneous growths of anatase and rutile phase during the first 30 minutes of annealing while the bulk sample oxidation leads to the nucleation of a small amount of anatase TiO<sub>2</sub>. The initial amorphous oxide layer created by anodization is also responsible for the delay in crystallization compared to the bulk sample. Thermogravimetric analysis exhibits parabolic shape of the mass gain for both anodized and bulk sample;this kinetics is caused by the formation of a rutile external protective layer, as depicted by the associated in-situ XRD diffractograms. We recorded that titanium dioxide nanotube layers exhibit a lower mean mass gain than the bulk, because of the presence of an initial amorphous oxide layer on anodized samples. In-situ XRD results also provide accurate information concerning the sub-layers behavior during the annealing treatment for the bulk and nanostructured layer. Anatase crystallites are mainly localized at the interface oxide layer-metal and the rutile is at the external interface. Sample surface topography was characterized using scanning electron microscopy (SEM). As a probe of the photoactivity of the annealed TiO<sub>2</sub> nanotube layers, degradation of an acid orange 7 (AO7) dye solution and 4-chlorophenol under UV irradiation (at 365 nm) were performed. Such titanium dioxide nanotube layers show an efficient photocatalytic activity and the analytical results confirm the degradation mechanism of the 4-chlorophenol reported elsewhere.展开更多
In the titanium dioxide industry,there is a lack of a low-cost and high-efficiency treatment method for chloride containing tail gas.In this paper,the removal of HCl from the titanium dioxide industry by gas cyclone-l...In the titanium dioxide industry,there is a lack of a low-cost and high-efficiency treatment method for chloride containing tail gas.In this paper,the removal of HCl from the titanium dioxide industry by gas cyclone-liquid jet separator was studied,while Ca(OH)_(2),Na_(2)CO_(3),NaOH solution,and water were used as absorbents.This paper investigated the influence of gas cyclone-liquid jet separator’s various process parameters on the removal rate of hydrogen chloride gas.The mechanism of mass transfer in the process of removing hydrogen chloride was discussed,and the effect and feasibility of HCl gas removal in the gas cyclone-liquid jet absorption separator were studied.The results showd that the removal efficiency of hydrogen chloride maintained above 95%,up to 99.9%,and the total mass transfer coefficient reached0.28 mol·m^(-3)·s^(-1)·k Pa^(-1).Under the same conditions,the absorption effect and total mass transfer coefficient of weak basic absorption liquid can be greatly improved by increasing the flow rate of absorption liquid,but the absorption effect and total mass transfer coefficient of strong alkaline absorption liquid can’t be improved obviously.The larger the inlet gas volume,the higher the gas concentration,the lower the absorption efficiency and the lower the total volumetric mass transfer coefficient.展开更多
A set of metal nanoparticle-decorated titanium dioxide(Mx/TiO_(2);where x is the percent by mass,%)photocatalysts was prepared via the sol-immobilization in order to enhance the simultaneous hydrogen(H_(2))production ...A set of metal nanoparticle-decorated titanium dioxide(Mx/TiO_(2);where x is the percent by mass,%)photocatalysts was prepared via the sol-immobilization in order to enhance the simultaneous hydrogen(H_(2))production and pollutant reduction from real biodiesel wastewater.Effect of the metal nanoparticle(NP)type(M=Ni,Au,Pt or Pd)and,for Pd,the amount(1%–4%)decorated on the surface of thermal treated commercial TiO_(2)(T_(400))was evaluated.The obtained results demonstrated that both the type and amount of decorated metal NPs did not significantly affect the pollutant reduction,measured in terms of the reduction of chemical oxygen demand(COD),biological oxygen demand(BOD)and oil&grease levels,but they affected the H_(2) production rate from both deionized water and biodiesel wastewater,which can be ranked in the order of Pt_(1)/T_(400)>Pd_(1)/T_(400)>Au_(1)/T_(400)>Ni_(1)/T_(400).This was attributed to the high difference in work function between Pt and the parent T400.However,the difference between Pt1/T400 and Pd1/T400 was not great and so from an economic consideration,Pd/TiO_(2) was selected as appropriate for further evaluation.Among the four different Pdx/TiO_(2) photocatalysts,the Pd3/TiO_(2) demonstrated the highest activity and gave a high rate of H_(2) production(up to 135 mmol·h−1)with a COD,BOD and oil&grease reduction of 30.3%,73.7%and 58.0%,respectively.展开更多
Lithium sulfur(Li-S)batteries demonstrate great promise for efficient energy storage systems once the lithium polysulfide(LPS)shuttling and sluggish redox kinetics can be well addressed.Herein,we developed a sea urchi...Lithium sulfur(Li-S)batteries demonstrate great promise for efficient energy storage systems once the lithium polysulfide(LPS)shuttling and sluggish redox kinetics can be well addressed.Herein,we developed a sea urchin-structured oxygen-deficient titanium dioxide semiconductor anchored with cobalt nano-dots(Co@TiO2-x)as a high-performance multifunctional sulfur host material for Li-S batteries.The sea urchin-structured Co@TiO2-x offers strong structural stability and strengthened chemical interaction towards LPS.Meanwhile,the incorporation of Co nano-dots into TiO2 leads to increased oxygen vacancies,which augments the electrical conduction and benefits LPS conversion acceleration as well.As a result,the oxygen vacancy-rich Co@TiO2-x composite exhibits excellent conductivity,strong LPS confinement and promoted sulfur electrochemical kinetics,rendering enhanced LPS shuttling inhibition and rapid redox reaction.Attributed to these features,the Co@TiO2-x/S cathode exhibits a discharge capacity of 803 mAh g-1at 1 C and a good cyclic stability upon 500 cycles with a low capacity fading rate of 0.07%per cycle.This synergistic design of conductive multifunctional LPS barrier is also promising to enlighten the material engineering in other energy storage applications.展开更多
In recent years,ionic liquids(ILs)have been widely used in extraction,synthesis,electrochemistry and other fields.Meanwhile,the environmental impact of ILs has been attracting a lot of attention,and eco-friendly treat...In recent years,ionic liquids(ILs)have been widely used in extraction,synthesis,electrochemistry and other fields.Meanwhile,the environmental impact of ILs has been attracting a lot of attention,and eco-friendly treatment for ILs is becoming a necessary subject.In this study,photocatalytic degradations of benzothiazole ILs catalyzed by titanium dioxide(TiO2)and silver-loaded titanium dioxide(Ag/TiO2)were studied for the first time.The degradation of benzothiazole hexafluorophosphate([C4 Bth]PF6)could reach more than 99%within 240 min with the catalysis of TiO2.To improve catalytic efficiency,Ag/TiO2 was synthesized and characterized by UV–Vis diffuse reflectance absorption spectra(DRS)and X-ray photoelectron spectroscopy(XPS).The degradation of[C4 Bth]PF6 could reach more than 99%within 120 min in the degradation catalyzed by Ag/TiO2.The photodegradation products of benzothiazole ILs are composed of inorganic substances or organic substances with simpler structures,which are easier to decompose and less toxic.The degradation system proposed by this study could provide a simple,green,safe,and economical method for the efficient treatment of benzothiazole ILs.展开更多
Titanium dioxide(TiO_(2))was recently employed to apply onto road surfaces to degrade the harmful compounds from vehicle emissions.However,it remains a challenging task to find a highly compatible pavement type for Ti...Titanium dioxide(TiO_(2))was recently employed to apply onto road surfaces to degrade the harmful compounds from vehicle emissions.However,it remains a challenging task to find a highly compatible pavement type for TiO_(2)application to achieve durable and efficient air-purifying performance.This study proposed to coat TiO_(2)particles onto semi-flexible pavement surface and tried to investigate an optimum coating method.Three coating methods,including direct mixing TiO_(2)(MT)with asphalt mixture,spraying dry TiO_(2)(ST)coating and watersolution-based TiO_(2)(WT)coating on semi-flexible pavement surface.To achieve this objective,semi-flexible samples were prepared to evaluate and compare the performances of three coating methods by employing resistance to wearing,NO removal efficiency tests and residual texture depth tests.It was found that the ST method not only provided better NO degrading efficiency but also improved the resistance to wearing than the other two methods.展开更多
A novel graphene oxide/titanium dioxide(GO/TiO_2) solvent-free nanofluid was firstly synthesized by employing GO, which was in-situ deposited by TiO_2 as the core and(3-Glycidyloxypropyl) trime thoxysilane(KH560) and ...A novel graphene oxide/titanium dioxide(GO/TiO_2) solvent-free nanofluid was firstly synthesized by employing GO, which was in-situ deposited by TiO_2 as the core and(3-Glycidyloxypropyl) trime thoxysilane(KH560) and polyetheramine-M2070 as the shell. The morphology and structure of GO/TiO_2 nanofluid were verified by Transmission electron microscopy(TEM), X-ray diffraction(XRD) analysis, Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS) and UV-vis absorption spectra. These studies confirmed that TiO_2 has been deposited onto GO with good dispersion, and the organic shell has been grafted onto the core successfully. Thermo gravimetric analysis(TGA) and viscosity analysis indicated that this nanoparticle hybrid material presented a liquid state without solvent at room temperature, and has great fluidity and thermal stability. The solubility investigation of GO/TiO_2 nanofluid revealed its excellent amphiphilicity and the potential as the functional nanocomposites.展开更多
Since many years ago, the substitution of cement by other cementitious supplementary elements has being a purpose for many researchers. This is to reduce the impact of producing cement on our environment. In this arti...Since many years ago, the substitution of cement by other cementitious supplementary elements has being a purpose for many researchers. This is to reduce the impact of producing cement on our environment. In this article, we are interested in the possibility of substituting cement with titanium dioxide and titanium dioxide + fly ash. To achieve this purpose, we have manufactured mortars and cement pastes specimens with different rates of replacement of cement by titanium dioxide (0%, 0.1%, 1%) on the one hand and titanium dioxide + fly ash on the overhand. The flexural and compressive strength of each specimen has been determined.展开更多
The aim of this study is to clarify the effect of different concentrations of titanium dioxide nanoparticles (Nps) on the properties of two types of heat polymerized acrylic resin. The tested parameters were flexural ...The aim of this study is to clarify the effect of different concentrations of titanium dioxide nanoparticles (Nps) on the properties of two types of heat polymerized acrylic resin. The tested parameters were flexural strength, impact strength, and microhardness. The two types of acrylic resin used in this study were conventional unmodified (Implacryl, Vertex) and high impact heat polymerized acrylic resin (Vertex-Dental, Netherlands). Both types of acrylic resin were modified by using 1% and 5% TiO<sub>2</sub> Nps powder. Specimen’s dimensions were prepared according to the American Dental Association Specification No. 12. Three types of specimens were prepared: 1) flexural strength specimens 50 mm × 10 (±0.2) mm × 3 (±0.2) mm, 2) impact strength test specimens 60 mm × 6.0 mm × 4.0 mm, 3) microhardnesss specimens 25 mm × 10 mm × 3 (±0.2) mm. For each test 6 groups were prepared (each group containing 5 samples). Thirty specimens were prepared in each of the three tests, amounting to a total number of 90 specimens. Mechanical properties such as flexural strength (FS), impact strength and microhardness of the above mentioned specimens were determined using universal testing machine, Izod pendulum impact testing machine and Vickers microhardness tester, respectively. ISO Specification No. 1567 was followed in microhardness test. The data was collected and statistically analyzed. Flexural strength considerably decreased by increasing TiO<sub>2</sub> concentration in both types of acrylic resin. Impact strength of the conventional acrylic resin modified by 1% of additives significantly increased. The microhardness is significantly increased by addition of 5% of TiO<sub>2</sub> Nps. The Incorporation of TiO<sub>2</sub> nanoparticles into acrylic resins can adversely affect its flexural strength. Meanwhile, the impact strength can be modified by small percentage of additives (abt. 1%). This effect is directly correlated with the concentration of nanoparticles. On the other hand, concentrations of TiO<sub>2</sub> Nps (abt. 5%) positively affect the microhardness of both types of acrylic resin used in the present study.</sub></sub></sub></sub></sub></sub></sub></sub></sub></sub>展开更多
文摘The use of titanium dioxide nanoparticles (nTiO<sub>2</sub>) is gaining interest in agriculture because of their impact on many aspects of plant growth. The present study examines the effects of nTiO<sub>2</sub> (5 nm and 10 nm) applied to seeds and the seedlings as a foliar application on various aspects of growth characteristics and biomass accumulation in lettuce (Lactuca sativa, cv. Grand Rapids). Application of 10 nm nTiO<sub>2</sub> to seeds through imbibition resulted in a significant reduction in shoot biomass accumulation while 5 nm nTiO<sub>2</sub> did not affect the biomass accumulation in lettuce. The application of 10 nm nTiO<sub>2</sub> reduced the fresh shoot biomass accumulation by about 18% compared to the control plants. Other growth characteristics such as shoot dry biomass, root fresh and dry biomass, plant height, and leaf area were not affected by the application of both 5 nm and 10 nm nTiO<sub>2</sub>. In addition, foliar application of these nanoparticles to the lettuce seedlings did not have a significant effect on most of the growth parameters examined, and the increasing concentration ranging from 5 nm/L to 400 mg/L did not produce a consistent response in lettuce. Thus, nTiO<sub>2</sub> application to lettuce seeds had a notable negative impact on shoot growth while foliar application did not have a significant effect on many plant growth characteristics. However, foliar applications produced some symptoms of toxicity to the foliage in the form of necrotic or chlorotic patches on the leaves, which were more pronounced with increasing concentrations of both 5 nm and 10 nm nTiO<sub>2</sub>. However, these symptoms were apparent at a concentration as low as 50 mg/L of nTiO<sub>2</sub>. Thus, foliar application of nTiO<sub>2</sub> may not have a significant impact on many of the growth characteristics in lettuce, but it can result in foliar toxicity.
基金Ho Chi Minh City University of Technology (HCMUT),VNU-HCM for supporting this study。
文摘In this study,three-dimensional porous magnesium ferrite/titanium dioxide/reduced graphene oxide(Mg Fe_2O_(4)-GM/TiO_(2)/rGO(MGTG))was successfully synthesized via green and hydrothermal-supported co-precipitation methods using the extract of Garcinia mangostana(G.mangostana)as a reducing agent.The characterization results indicate the successful formation of the nano/micro Mg Fe_(2)O_(4)(MFO)and TiO_(2) on the structure of the reduced graphene oxide(rGO),which can also act as efficient support,alleviating the agglomeration of the nano/micro MFO and TiO_(2).The synergic effects of the adsorption and photodegradation activity of the material were investigated according to the removal of crystal violet(CV)under ultraviolet light.The effects of catalyst dosage,CV concentration,and p H on the CV removal efficiency of the MGTG were also investigated.According to the results,the CV photodegradation of the MGTG-200 corresponded to the pseudo-first-order kinetic model.The reusability of the material after 10 cycles also showed a removal efficiency of 92%.This happened because the materials can easily be recollected using external magnets.In addition,according to the effects of different free radicals·O_(2)^(-),h^(+),and·OH on the photodegradation process,the photocatalysis mechanism of the MGTG was also thoroughly suggested.The antibacterial efficiency of the MGTG was also evaluated according to the inhibition of the Gram-positive bacteria strain Staphylococcus aureus(S.aureus).Concurrently,the antibacterial mechanism of the fabricated material was also proposed.These results confirm that the prepared material can be potentially employed in a wide range of applications,including wastewater treatment and antibacterial activity.
基金financially supported by the National Natural Science Foundation of China (No.51874099)the National Science Foundation of Fujian Province’s Key Project,China (No.2021J02031)the support from the open fund from the Academy of Carbon Neutrality of Fujian Normal University,China (No.CZH2022-06)。
文摘To meet the low-cost concept advocated by the sodium metal anode,this paper reports the use of a pulsed electrodeposition technology with ionic liquids as electrolytes to achieve uniform nanoplating of metallic magnesium films at around 20 nm on spaced titanium dioxide(TiO_(2))nanotubes(STNA-Mg).First,the sodiophilic magnesium metal coating can effectively reduce the nucleation overpotential of sodium metal.Moreover,three-dimensional STNA can limit the volume expansion during sodium metal plating and stripping to achieve the ultrastable deposition and stripping of sodium metals with a high Coulombic efficiency of up to 99.5%and a small voltage polarization of 5 mV in symmetric Na||Na batteries.In addition,the comparative study of sodium metal deposition behavior of STNA-Mg and STNA-Cu prepared by the same route further confirmed the advantage of magnesium metal to guide sodium metal growth.Finally,the prepared STNA-Mg-Na metal anode and commercial sodium vanadium phosphate cathode were assembled into a full cell,delivering a discharge capacity of 110.2 mAh·g^(-1)with a retention rate of 95.6%after 110 cycles at 1C rate.
基金supported by the National Natural Science Foundation of China(No.22108108,22205108,and No.22108106)China Postdoctoral Science Foundation No.2022M721381.
文摘Extremely high-temperature and high-pressure requirement of Haber-Bosch process motivates the search for a sustainable ammonia synthesis approach under mild conditions.Photocatalytic technology is a potential solution to convert N2 to ammonia.However,the poor light absorption and low charge carrier separation efficiency in conventional semiconductors are bottlenecks for the application of this technology.Herein,a facile synthesis of anatase TiO_(2)nanosheets with an abundance of surface oxygen vacancies(TiO_(2)-OV)via the calcination treatment was reported.Photocatalytic experiments of the prepared anatase TiO_(2)samples showed that TiO_(2)-OV nanosheets exhibited remarkably increased ammonia yield for solar-driven N2 fixation in pure water,without adding any sacrificial agents.EPR,XPS,XRD,UV-Vis DRS,TEM,Raman,and PL techniques were employed to systematically explore the possible enhanced mechanism.Studies revealed that the introduced surface oxygen vacancies significantly extended the light absorption capability in the visible region,decreased the adsorption and activation barriers of inert N2,and improved the separation and transfer efficiency of the photogenerated electronhole pairs.Thus,a high rate of ammonia evolution in TiO_(2)-OV was realized.This work offers a promising and sustainable approach for the efficient artificial photosynthesis of ammonia.
文摘Titanium dioxide Nanotubes(TNTs) prepared by electroless deposition have been annealed at air ambient and low temperature. As a result, the anatase/rutile phase composition of the TNTs can be tailored to the needs of later applications. Nanotubes with anatase/rutile mixed phase ratio of 4:1 have been produced in this report and further examined for their photocatalytical behavior. The photocatalytical properties of the TNTs have been observed by degradation of methylene-blue in aqueous solution under low power UV-light irradiation. The results shown in this report are based on the synergetic effect between rutile and anatase,which results in the mixed phase TiO 2 nanotubes having enhanced photocatalytical properties.
基金supported by the National Natural Science Foundation of China(Nos.21776034,21476044 and 21406031)Joint Funds of the National Natural Science Foundation of China(U1663223)+1 种基金National Key Research and Development Program of China(2016YFB0101203)Changjiang Scholars Program(T2012049)。
文摘The novel sulfonated polybenzimidazole(sPBI)/amine functionalized titanium dioxide(AFT) composite membrane is devised and studied for its capability of the application of high temperature proton exchange membrane fuel cells(HT-PEMFCs),unlike the prior low temperature AFT endeavors.The high temperature compatibility was actualized because of the filling of free volumes in the rigid aromatic matrix of the composite with AFT nanoparticles which inhibited segmental motions of the chains and improved its thermal stability.Besides,amine functionalization of TiO2 enhanced their dispersion character in the sPBI matrix and shortened the interparticle separation gap which finally improved the proton transfer after establishing interconnected pathways and breeding more phosphoric acid(PA) doping.In addition,the appeared assembled clusters of AFT flourished a superior mechanical stability.Thus,the optimized sPBI/AFT(10 wt%) showed 65.3 MPa tensile strength;0.084 S·cm^-1 proton conductivity(at 160℃;in anhydrous conditions),28.6% water uptake and PA doping level of 23 mol per sPBI repeat unit.The maximum power density peak for sPBI/AFT-10 met the figure of0.42 W·cm^-2 at 160℃(in dry conditions) under atmospheric pressure with 1.5 and 2.5 stoichiometric flow rates of H2/air.These results affirmed the probable fitting of sPBI/AFT composite for HT-PEMFC applications.
文摘Titanium dioxide(Ti O_(2))nanopowder(P-25;Degussa AG)was treated using dielectric barrier discharge(DBD)in a rotary electrode DBD(RE-DBD)reactor.Its electrical and optical characteristics were investigated during RE-DBD generation.The treated TiO_(2)nanopowder properties and structures were analyzed using x-ray diffraction(XRD)and Fourier-transform infrared spectroscopy(FTIR).After RE-DBD treatment,XRD measurements indicated that the anatase peak theta positions shifted from 25.3°to 25.1°,which can be attributed to the substitution of new functional groups in the TiO_(2)lattice.The FTIR results show that hydroxyl groups(OH)at 3400 cm-1 increased considerably.The mechanism used to modify the TiO_(2)nanopowder surface by air DBD treatment was confirmed from optical emission spectrum measurements.Reactive species,such as OH radical,ozone and atomic oxygen can play key roles in hydroxyl formation on the TiO_(2)nanopowder surface.
文摘Titanium dioxide nanotubes(TNTs)were prepared by electroless deposition using ion track etched polycarbonate templates.The ion tracks were prepared to the desired diameter of the TNTs outer diameter.Titanium dioxide nanotubes with a diameter of minimum 80 nm having a wall thickness of minimum 10 nm can be fabricated using this method.To achieve nanotubes with thin walls and small surface roughness the tubes were generated by a several steps procedure under aqueous conditions at nearly room temperature.The presented approach will process open end nanotubes with well defined outer diameter and wall thickness.Using this method TNT arrays up to 109 tubes per cm2having a tube length up to 30μm can be produced,single tubes are also possible.The structural properties of the grown TNTs were investigated by using various analytical techniques,i.e.scanning electron microscopy(SEM),energy dispersive X-ray fluoresence spectrometer(EDX),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),Raman spectroscopy and Photoluminescence.
基金the National Natural Science Foundation of China(Grant No.51408162)the Special Financial Grant from the China Postdoctoral Science Foundation(Grant No.2016T90303)+1 种基金the China Postdoctoral Science Foundation(Grant No.2014M551258)the Heilongjiang Province Postdoctoral Science Foundation(Grant No.LBH-Z14077)。
文摘At present,a growing number of consumer products contain engineered nanoparticle TiO2(nano⁃TiO2),which has resulted in the consequences of nano⁃TiO2 entering the aquatic environment directly or indirectly at some stage.The fate of nano⁃TiO2 in the aquatic environment has become the key factor which affects its safety application and nanoecotoxicology.This paper aims to investigate how the dissolved organic matters(DOM),especially the molecular weight fractions in the aquatic environment,affect the aggregation,stability,and fate of nano⁃TiO2,and the interaction mechanism of DOM and nano⁃TiO2.Results of dynamic light scattering(DLS)showed that the molecular weight of DOM molecules caused different aggregation rates of nano⁃TiO2 in aqueous solution.Fourier Transform infrared spectroscopy(FTIR)results indicated the molecular structure is characteristics of DOM fractions and the mechanisms of bonds formation between DOM and nano⁃TiO2.Results of three⁃dimensional excitation⁃emission matrices(3D⁃EEM)confirmed the FTIR results and implied the increase of the stability of theπ-πconjugated system in the presence of DOM.In addition,low molecular weight of DOM fractions appeared to show more affinity with nano⁃TiO2 than high molecular weight fractions.
基金This research has been partially supported by the Government of Andalusia’s project“Characterization and modelling of the phosphogypsum stacks from Huelva for their environmental management and control”(Ref.:RNM-6300) by National Institution of Higher Education,Science,Technology and Innovation of the Republic of Ecuador-(SENESCYT for its acronym in Spanish)+2 种基金The authors would like to acknowledge the financial support received from the company Tioxide-Huelva by the research projects“Valorization of red gypsum from the industrial production of titanium dioxide”(PROFIT,CIT-310200-2007-47)“Applications of red gypsum and Tionite waste in commercial applications”The authors also thank to the technical staff for the advisory provided in the explanation of the results.
文摘Titanium is a very important element for several industrial applications, being one of the ninth most abundant elements in the Earth’s crust (0.63% wt). In this work it will discuss the different mining and industrial activities involved in the production of titanium dioxide. The first step analyzed will treat about the beneficiation mining process of titanium mineral, and secondly, it will discuss the two main processes of the TiO2 manufacturing (sulphate and chloride routes). In addition, we will show different uses of the titanium dioxide pigment as filler in paper, plastics and rubber industries and as flux in glass manufacture, etc. Finally, we will show that the old wastes are currently called co-products since they were valorized, being commercialized by the Spanish industry of TiO2 production in different fields such as agriculture, civil engineering, or cement manufacturing.
文摘The performance of local clay-titanium dioxide core-shell extender pigments in alkyd paints has been studied. The physico-mechanical properties of the prepared alkyd paints were evaluated according to ASTM measurements. The effects of various environmental and corrosive factors on the paints were also studied. The study showed that the alkyd paint samples formulated using the core-shell pigments generally had low specific gravity (1.30 – 1.38), an indication that more of the core-shell pigments can be incorporated into the alkyd paints with considerable cost savings. The dry film thicknesses of the paint samples falls within 0.24 - 0.39 mm, suggesting that the samples will perform well as anticorrosive coatings and their adhesion properties are generally good, showing that they can withstand abrasive and corrosive agents. The core-shell extender pigments formulated paint samples were observed to exhibit the best dust-free, tack-free, and through dry times compared to TiO<sub>2</sub> paint formulation. The formulated paint samples generally performed well on exposure to rain and sunlight as well as in distilled water, 2% Na<sub>2</sub>CO<sub>3</sub>, and 2% H<sub>2</sub>SO<sub>4</sub> with only TiO<sub>2</sub> paint formulation exhibiting rust. The good paint performance characteristics obtainable with the core-shell extender pigments are enough evidence to justify their utilization in the surface coatings industry. The performances of these core-shell extender pigments in alkyd paints have shown that they combine the properties of both the clays and titanium dioxide, and have the potential to overcome their disadvantages.
文摘In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs to be better understood. Nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoric acid solution during 20 minutes and then annealed in air atmosphere. In-situ X-ray diffraction analysis, coupled with thermogravimetry, gives us an inside on the oxidation behaviour of titanium dioxide nanotube layers compared to bulk reference samples. Structural studies were performed at 700°C for 12 h in order to follow the time consequences on the oxidation of the material, in sufficient stability conditions. In-situ XRD brought to light that the amorphous oxide layer induced by anodization is responsible for the simultaneous growths of anatase and rutile phase during the first 30 minutes of annealing while the bulk sample oxidation leads to the nucleation of a small amount of anatase TiO<sub>2</sub>. The initial amorphous oxide layer created by anodization is also responsible for the delay in crystallization compared to the bulk sample. Thermogravimetric analysis exhibits parabolic shape of the mass gain for both anodized and bulk sample;this kinetics is caused by the formation of a rutile external protective layer, as depicted by the associated in-situ XRD diffractograms. We recorded that titanium dioxide nanotube layers exhibit a lower mean mass gain than the bulk, because of the presence of an initial amorphous oxide layer on anodized samples. In-situ XRD results also provide accurate information concerning the sub-layers behavior during the annealing treatment for the bulk and nanostructured layer. Anatase crystallites are mainly localized at the interface oxide layer-metal and the rutile is at the external interface. Sample surface topography was characterized using scanning electron microscopy (SEM). As a probe of the photoactivity of the annealed TiO<sub>2</sub> nanotube layers, degradation of an acid orange 7 (AO7) dye solution and 4-chlorophenol under UV irradiation (at 365 nm) were performed. Such titanium dioxide nanotube layers show an efficient photocatalytic activity and the analytical results confirm the degradation mechanism of the 4-chlorophenol reported elsewhere.
基金the sponsorship of National Natural Science Foundation of China(21878099)Science and Technology Commission of Shanghai Municipality(19DZ1208000)。
文摘In the titanium dioxide industry,there is a lack of a low-cost and high-efficiency treatment method for chloride containing tail gas.In this paper,the removal of HCl from the titanium dioxide industry by gas cyclone-liquid jet separator was studied,while Ca(OH)_(2),Na_(2)CO_(3),NaOH solution,and water were used as absorbents.This paper investigated the influence of gas cyclone-liquid jet separator’s various process parameters on the removal rate of hydrogen chloride gas.The mechanism of mass transfer in the process of removing hydrogen chloride was discussed,and the effect and feasibility of HCl gas removal in the gas cyclone-liquid jet absorption separator were studied.The results showd that the removal efficiency of hydrogen chloride maintained above 95%,up to 99.9%,and the total mass transfer coefficient reached0.28 mol·m^(-3)·s^(-1)·k Pa^(-1).Under the same conditions,the absorption effect and total mass transfer coefficient of weak basic absorption liquid can be greatly improved by increasing the flow rate of absorption liquid,but the absorption effect and total mass transfer coefficient of strong alkaline absorption liquid can’t be improved obviously.The larger the inlet gas volume,the higher the gas concentration,the lower the absorption efficiency and the lower the total volumetric mass transfer coefficient.
文摘A set of metal nanoparticle-decorated titanium dioxide(Mx/TiO_(2);where x is the percent by mass,%)photocatalysts was prepared via the sol-immobilization in order to enhance the simultaneous hydrogen(H_(2))production and pollutant reduction from real biodiesel wastewater.Effect of the metal nanoparticle(NP)type(M=Ni,Au,Pt or Pd)and,for Pd,the amount(1%–4%)decorated on the surface of thermal treated commercial TiO_(2)(T_(400))was evaluated.The obtained results demonstrated that both the type and amount of decorated metal NPs did not significantly affect the pollutant reduction,measured in terms of the reduction of chemical oxygen demand(COD),biological oxygen demand(BOD)and oil&grease levels,but they affected the H_(2) production rate from both deionized water and biodiesel wastewater,which can be ranked in the order of Pt_(1)/T_(400)>Pd_(1)/T_(400)>Au_(1)/T_(400)>Ni_(1)/T_(400).This was attributed to the high difference in work function between Pt and the parent T400.However,the difference between Pt1/T400 and Pd1/T400 was not great and so from an economic consideration,Pd/TiO_(2) was selected as appropriate for further evaluation.Among the four different Pdx/TiO_(2) photocatalysts,the Pd3/TiO_(2) demonstrated the highest activity and gave a high rate of H_(2) production(up to 135 mmol·h−1)with a COD,BOD and oil&grease reduction of 30.3%,73.7%and 58.0%,respectively.
基金support from the National Natural Science Foundation of China(21978063)the“Excellent Going Abroad Experts”Training Program in Hebei ProvinceInnovation Fund for Excellent Youth of Hebei University of Technology(2012002)。
文摘Lithium sulfur(Li-S)batteries demonstrate great promise for efficient energy storage systems once the lithium polysulfide(LPS)shuttling and sluggish redox kinetics can be well addressed.Herein,we developed a sea urchin-structured oxygen-deficient titanium dioxide semiconductor anchored with cobalt nano-dots(Co@TiO2-x)as a high-performance multifunctional sulfur host material for Li-S batteries.The sea urchin-structured Co@TiO2-x offers strong structural stability and strengthened chemical interaction towards LPS.Meanwhile,the incorporation of Co nano-dots into TiO2 leads to increased oxygen vacancies,which augments the electrical conduction and benefits LPS conversion acceleration as well.As a result,the oxygen vacancy-rich Co@TiO2-x composite exhibits excellent conductivity,strong LPS confinement and promoted sulfur electrochemical kinetics,rendering enhanced LPS shuttling inhibition and rapid redox reaction.Attributed to these features,the Co@TiO2-x/S cathode exhibits a discharge capacity of 803 mAh g-1at 1 C and a good cyclic stability upon 500 cycles with a low capacity fading rate of 0.07%per cycle.This synergistic design of conductive multifunctional LPS barrier is also promising to enlighten the material engineering in other energy storage applications.
文摘In recent years,ionic liquids(ILs)have been widely used in extraction,synthesis,electrochemistry and other fields.Meanwhile,the environmental impact of ILs has been attracting a lot of attention,and eco-friendly treatment for ILs is becoming a necessary subject.In this study,photocatalytic degradations of benzothiazole ILs catalyzed by titanium dioxide(TiO2)and silver-loaded titanium dioxide(Ag/TiO2)were studied for the first time.The degradation of benzothiazole hexafluorophosphate([C4 Bth]PF6)could reach more than 99%within 240 min with the catalysis of TiO2.To improve catalytic efficiency,Ag/TiO2 was synthesized and characterized by UV–Vis diffuse reflectance absorption spectra(DRS)and X-ray photoelectron spectroscopy(XPS).The degradation of[C4 Bth]PF6 could reach more than 99%within 120 min in the degradation catalyzed by Ag/TiO2.The photodegradation products of benzothiazole ILs are composed of inorganic substances or organic substances with simpler structures,which are easier to decompose and less toxic.The degradation system proposed by this study could provide a simple,green,safe,and economical method for the efficient treatment of benzothiazole ILs.
基金The authors would like to acknowledge the Science Technology Department of Zhejiang Province(Grant Nos.2018F10045 and 2021C01106)for the funding support and the technical guidance in 3D laser scanning by Dr.Fengxia Chi from the Institute of Road Engineering of Zhejiang Scientific Research Institute of TransportThe constant of this paper reflects the views of authors,who are responsible for the facts and the accuracy of the data shown herein.The authors gratefully acknowledge their financial and technical supporting.
文摘Titanium dioxide(TiO_(2))was recently employed to apply onto road surfaces to degrade the harmful compounds from vehicle emissions.However,it remains a challenging task to find a highly compatible pavement type for TiO_(2)application to achieve durable and efficient air-purifying performance.This study proposed to coat TiO_(2)particles onto semi-flexible pavement surface and tried to investigate an optimum coating method.Three coating methods,including direct mixing TiO_(2)(MT)with asphalt mixture,spraying dry TiO_(2)(ST)coating and watersolution-based TiO_(2)(WT)coating on semi-flexible pavement surface.To achieve this objective,semi-flexible samples were prepared to evaluate and compare the performances of three coating methods by employing resistance to wearing,NO removal efficiency tests and residual texture depth tests.It was found that the ST method not only provided better NO degrading efficiency but also improved the resistance to wearing than the other two methods.
基金supported by the National Natural Science Foundation of China(51373137)the International cooperation project of Shaanxi Province(2016KW-053)the Natural Science Basic Research Plan in Shaanxi(2017JQ2002)
文摘A novel graphene oxide/titanium dioxide(GO/TiO_2) solvent-free nanofluid was firstly synthesized by employing GO, which was in-situ deposited by TiO_2 as the core and(3-Glycidyloxypropyl) trime thoxysilane(KH560) and polyetheramine-M2070 as the shell. The morphology and structure of GO/TiO_2 nanofluid were verified by Transmission electron microscopy(TEM), X-ray diffraction(XRD) analysis, Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS) and UV-vis absorption spectra. These studies confirmed that TiO_2 has been deposited onto GO with good dispersion, and the organic shell has been grafted onto the core successfully. Thermo gravimetric analysis(TGA) and viscosity analysis indicated that this nanoparticle hybrid material presented a liquid state without solvent at room temperature, and has great fluidity and thermal stability. The solubility investigation of GO/TiO_2 nanofluid revealed its excellent amphiphilicity and the potential as the functional nanocomposites.
文摘Since many years ago, the substitution of cement by other cementitious supplementary elements has being a purpose for many researchers. This is to reduce the impact of producing cement on our environment. In this article, we are interested in the possibility of substituting cement with titanium dioxide and titanium dioxide + fly ash. To achieve this purpose, we have manufactured mortars and cement pastes specimens with different rates of replacement of cement by titanium dioxide (0%, 0.1%, 1%) on the one hand and titanium dioxide + fly ash on the overhand. The flexural and compressive strength of each specimen has been determined.
文摘The aim of this study is to clarify the effect of different concentrations of titanium dioxide nanoparticles (Nps) on the properties of two types of heat polymerized acrylic resin. The tested parameters were flexural strength, impact strength, and microhardness. The two types of acrylic resin used in this study were conventional unmodified (Implacryl, Vertex) and high impact heat polymerized acrylic resin (Vertex-Dental, Netherlands). Both types of acrylic resin were modified by using 1% and 5% TiO<sub>2</sub> Nps powder. Specimen’s dimensions were prepared according to the American Dental Association Specification No. 12. Three types of specimens were prepared: 1) flexural strength specimens 50 mm × 10 (±0.2) mm × 3 (±0.2) mm, 2) impact strength test specimens 60 mm × 6.0 mm × 4.0 mm, 3) microhardnesss specimens 25 mm × 10 mm × 3 (±0.2) mm. For each test 6 groups were prepared (each group containing 5 samples). Thirty specimens were prepared in each of the three tests, amounting to a total number of 90 specimens. Mechanical properties such as flexural strength (FS), impact strength and microhardness of the above mentioned specimens were determined using universal testing machine, Izod pendulum impact testing machine and Vickers microhardness tester, respectively. ISO Specification No. 1567 was followed in microhardness test. The data was collected and statistically analyzed. Flexural strength considerably decreased by increasing TiO<sub>2</sub> concentration in both types of acrylic resin. Impact strength of the conventional acrylic resin modified by 1% of additives significantly increased. The microhardness is significantly increased by addition of 5% of TiO<sub>2</sub> Nps. The Incorporation of TiO<sub>2</sub> nanoparticles into acrylic resins can adversely affect its flexural strength. Meanwhile, the impact strength can be modified by small percentage of additives (abt. 1%). This effect is directly correlated with the concentration of nanoparticles. On the other hand, concentrations of TiO<sub>2</sub> Nps (abt. 5%) positively affect the microhardness of both types of acrylic resin used in the present study.</sub></sub></sub></sub></sub></sub></sub></sub></sub></sub>
