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This study investigates the comparative effects of carboxyl-functionalized multi-walled carbon nanotube (MWCNT)/water nanofluids and titanium dioxide (TiO2) /water nanofluids in direct absorption parabolic solar collectors. To achieve this, a standard testing apparatus was constructed, and the thermal and exergy efficiencies of the collector were calculated using nanofluids at various concentrations. UV/Vis analysis was used to analyze the radiative properties of the nanofluids, and their thermal conductivity was also measured. Experiments were conducted under laminar flow conditions with flow rates of 20, 60, and 100 liters per hour and inlet temperatures of 20, 30, and 40 °C under real conditions with direct solar irradiation. The highest thermal efficiency recorded for the carbon-based nanofluid was 44.96%, while the titanium-based nanofluid achieved a thermal efficiency of 34.98%. Given the substantial improvement in efficiency compared to the base fluid (distilled water), the combined effect of using both nanofluids was also examined, resulting in a maximum thermal efficiency of 48.77%. The exergy efficiency at the highest flow rate and inlet temperature for the base fluid, TiO2 nanofluid, MWCNT nanofluid, and the hybrid nanofluid were 2.61%, 4.98%, 6.68%, and 7.26%, respectively. The pressure drop of all nanofluids in the absorber tube ranged from 5 to 39.6 Pascals. The studied nanofluids enhance the thermal performance of the system and create low pressure drop, indicating their high efficiency in direct absorption solar collectors. [ABSTRACT FROM AUTHOR]

Background: Antibiotics are among the environmental pollutants with stable effects during consumption, they are rarely completely metabolized in the body and 30-90% of them are excreted through urine and feces and enter into the environment. The present study was conducted to evaluate the degradation of cefixime pollutant by photocatalyst Fe3O4@SiO2@TiO2@rGO + UV in the presence of persulfate (PS) from synthetic wastewater. Methods: Fe3O4@SiO2@TiO2 (F@ST) photocatalyst was synthesized by co-precipitation method, and then fixed on reduced graphene oxide (rGO). The structural properties of magnetic photocatalyst were evaluated using FESEM, XRD, TEM, VSM techniques. The effect of variables such as solution pH, catalyst dosage, persulfate concentration and initial pollutant concentration on the performance of the FS@T/rGO/PS/UV process in the degradation of cefixime pollutant was investigated. After determining the optimal conditions, the influence of interfering ions and scavengers on the process, as well as the amount of recovery and reuse of the catalyst were investigated. Results: The synthesized photocatalyst had features such as excellent magnetic properties, crystalline and relatively spherical structure in nano size, high purity, photocatalytic properties in both ultraviolet and visible ranges. Under optimal conditions (pH=6.5-7, PS= 2mM and photocatalyst dosage= 0.1 g/L), after 60 min of oxidation time, cefixime antibiotic with a concentration of 50 mg/L and TOC, respectively, with efficiency > 98% and 55.7% were removed. The performance of the process was affected by the presence of organic scavengers (TBA, NaN3, KI and CH3OH) and interfering ions (Cl-, SO4-2, NO3- and CO3-2); so that the pollutant degradation efficiency decreased in the presence of organic scavengers and interfering ions. The effective reaction species were included h⁺, 1O2, OH• and SO4•⁻ in the degradation of cefixime by photocatalytic process in the presence of PS. The synthesized photocatalyst could be used for 4 consecutive steps, and in the fourth step, cefixime was degraded with an efficiency of 70.1%. The behavior of the photocatalytic degradation of cefixime antibiotic per unit time was a function of the pseudo-first-order kinetic model. Conclusion: : FS@T/rGO/UV/PS photocatalytic process with features such as high efficiency in antibiotic degradation, easy and fast separation, pollutant mineralization, production of side products with simple molecular structure and good performance on the real wastewater sample could be used as a suitable method for industrial wastewater post-treatment as well as pre-treatment in order to reduce organic load and increase biodegradability.

Hypothesis: Considering water quality problems and strict rules established for drinking water treatment, there is an urgent need to use more effective and economical methods to remove natural organic matter from water. Meanwhile, membrane processes are one of the effective methods to remove these pollutants. In this way, in order to prepare a membrane with a high ability to remove pollutants, in the present study, the production and optimization of poly(vinyl chloride) (PVC) membranes with poly(ethylene glycol) (PEG) additives have been carried out.Methods: PVC microporous membranes were prepared by nonsolvent-induced phase separation method. Influential parameters in the membrane fabrication, including the concentration of PVC and PEG and the composition of the coagulation bath were optimized using the response surface methodology (RSM). Meanwhile, tensile strength and porosity were considered as responses.Findings: The obtained results showed that all the membranes had an asymmetric structure with finger like pores. It was also found that the tensile strength of the membranes increased with the increase in PVC concentration. The lowest tensile strength was related to the membrane made of 10.30% (by wt) of PVC, while the membrane made of 18.7 % (by wt) of PVC had the highest tensile strength. In addition, for the optimum membrane in which the concentration of PVC was 17.52% (by wt), the concentration of PEG was 5.87% (by wt) and the volume fraction of ethanol in the coagulation bath was 0.27, the tensile strength and porosity of the membranes were obtained as 5 MPa and 80.57, respectively. Furthermore, in the following, titanium dioxide nanoparticles (TiO2) were used to prepare the composite membrane under the aforementioned optimum conditions. The obtained results showed that the optimum membrane containing 2% (by wt) of nanoparticles had the highest humic acid separation efficiency with a value of 80%.

Background and purpose: Toluene, is usually present in gasoline, thinner, and other petroleum products and is one of the volatile organic compounds that causes air pollution and adverse health effects. The aim of this study was to determine the kinetics of toluene removal from the air by photocatalytic method using foam glass coated with titanium dioxide nanoparticles. Materials and methods: In this experimental study, a glass chamber was used as a closed space. A quartz tube filled by glass foam coated with titanium dioxide nanoparticles was used as air filter. The air filter was placed inside the chamber and an air suction pump was connected to it and a UV lamp was installed next to the air filter. Toluene was injected into the chamber. The contaminated air was passed through the filter and circulated in the chamber. Air samples were taken from the chamber and concentration of toluene was analyzed by Gas Chromatograph. Results: Brunauer-Emmett-Teller (BET) analysis showed that the average diameter of pores in glass foam was 6 nm and the specific surface area of foam glass was 36 m2/g. The SEM images confirmed coating of titanium dioxide on the surface of glass foam. Toluene removal without UV irradiation was 46%, 40%, and 37%, for 18.5, 37, and 55.5 mg/m3, respectively in 2 hour contact time, but in the presence of UV radiation the toluene removal was 100%, 95%, and 90%, respectively in contact time of 80 min. The kinetics of toluene decomposition was pseudo first order. Conclusion: Glass foam can be used as a photocatalyst stabilization base to remove BTEX from the air. This is a suitable method in removing volatile organic compounds from the air in closed spaces.

Green chemistry plays an important role due to its involvement in unusual syntheses of metal nanoparticles from plant extracts, which have antimicrobial potential. Therefore, green synthesis of nanoparticles from plant extracts is a suitable way to produce nanoparticles. Therefore, the aim of this research was to synthesize Sabznano Ag / AgCl / TiO2 composite using aqueous extract of Shirazi thyme, to evaluate the size and morphology of the produced nanoparticles. For this purpose, synthesis and characterization of ternary Ag / AgCl / TiO2 nanocomposite using Shirazi thyme plant was done with the help of UV-Vis, XRD, TEM, FTIR techniques. Then the antimicrobial property of nanocomposites was investigated. The results showed that the maximum diameter of the halo of non-growth in all investigated bacteria is observed in the nanocomposite containing 50% chlorine and in the nanocomposite containing 5% (Ag / TiO2mol).The diameter of the non-growth halo increased from 0.5% to 3% in the film containing TiO2 / Ag / AgCl nanoparticles in all investigated microorganisms. Also, TEM images showed the uniform loading of Ag / AgCl nanoparticles on the TiO2 surface. In general, the obtained results indicate the fact that thyme extract, along with silver and titanium dioxide nanocomposites, has a high potential in the production of nanoparticles with high purity and in nanometer sizes and with antimicrobial properties and application in the food industry as It has cover and film. [ABSTRACT FROM AUTHOR]

Background and purpose: Toluene, is usually present in gasoline, thinner, and other petroleum products and is one of the volatile organic compounds that causes air pollution and adverse health effects. The aim of this study was to determine the kinetics of toluene removal from the air by photocatalytic method using foam glass coated with titanium dioxide nanoparticles. Materials and methods: In this experimental study, a glass chamber was used as a closed space. A quartz tube filled by glass foam coated with titanium dioxide nanoparticles was used as air filter. The air filter was placed inside the chamber and an air suction pump was connected to it and a UV lamp was installed next to the air filter. Toluene was injected into the chamber. The contaminated air was passed through the filter and circulated in the chamber. Air samples were taken from the chamber and concentration of toluene was analyzed by Gas Chromatograph. Results: Brunauer-Emmett-Teller (BET) analysis showed that the average diameter of pores in glass foam was 6 nm and the specific surface area of foam glass was 36 m² /g. The SEM images confirmed coating of titanium dioxide on the surface of glass foam. Toluene removal without UV irradiation was 46%, 40%, and 37%, for 18.5, 37, and 55.5 mg/m3, respectively in 2 hour contact time, but in the presence of UV radiation the toluene removal was 100%, 95%, and 90%, respectively in contact time of 80 min. The kinetics of toluene decomposition was pseudo first order. Conclusion: Glass foam can be used as a photocatalyst stabilization base to remove BTEX from the air. This is a suitable method in removing volatile organic compounds from the air in closed spaces. [ABSTRACT FROM AUTHOR]

Due to strong oxidizing properties, titanium dioxide or titania nanoparticles are widely used in the water and wastewater treatment industry to remove or reduce various contaminants. The extraordinary properties of titania have led to the neglect of its side effects on the environment, especially on the aquatic ecosystems. In this study, different concentrations of titania nanoparticles were used over a period of 96 hours in lab scale to evaluate their impact on the heavy metals distribution in an aqueous media. The sediment samples of Anzali wetland contaminated with heavy metals were applied in all experiments. The results revealed that arsenic (As) was strongly affected by titania nanoparticles and its exchangeable bonds were desorbed from the sediment. Subsequently, 50 ppb titania led to concentration of As in the water column, which increased from 0 to 9 ppb. In addition to As, nickel (Ni) was desorbed from sediment through the separation of its organic bonds. On the other hand, 50 ppb titania reduced the concentrations of manganese (Mn), copper (Cu) and zinc (Zn) in the water column from 42, 32 and 29 ppb to 17.7, 2.87 and 20.9 ppb, respectively. According to the chemical extraction analysis, heavy metals adsorption in the sediment was mainly in the form of exchangeable and sulfide bonds. However, lead (Pb) and cobalt (Co) were not affected by titania and exhibited a conservative behavior.

Among the methods used to remove heavy metals are membrane processes that, with less use of chemicals, are able to quickly produce high-quality penetration. In this study, a nanocomposite membrane with the ability to separate lead was used. The black titanium dioxide nanoparticle was synthesized using the pyrolysis method. Adsorption experiments were performed using a nanofiltration unit. The results of lead adsorption isotherms showed that the lead adsorption process using the membrane follows the Langmuir model with a correlation coefficient of 0.995. The results of the study of lead metal adsorption kinetics showed that the process of adsorption of lead by the adsorbent follows the quasi-second order kinetics so that the correlation coefficient of the second-order quasi-model is equal to 0.999 which is compared with the quasi-correlation coefficient. The maximum and minimum fluxes between different membranes were related to 0.1 mg/l of titanium dioxide nanoparticles in terms of time and pressure for 50 and 600 minutes and pressures of 45 and 145 bar, with increasing the initial concentration of pollutants, the percentage of adsorption decreases. This can be due to the delay in balancing the adsorbent and the contaminant.

In this paper, the titanium dioxide thin films were electrodeposited on the aluminum substrate. In electrodeposition, a pure or alloy material is deposited on a conductive or a semiconductor substrate from a solution by the passage of an electric current via two or three electrodes. The structure of TiO2 thin film with 1000 nm thickness was studied by X-ray diffraction. The crystallite size of the thin film was obtained about 41 nm via Debye– Scherrer equation. Also, the crystallite size and strain of lattice calculated by Williamson– Hall equation were about 46 nm and 0.004, respectively. The film surface roughness was investigated using an atomic force microscope (AFM). The logarithmic plots of roughness as a function of scan length for titanium dioxide films indicate that the film roughness increases as the film thickness increases. The electrodeposited TiO2 films exhibit anomalous scaling roughness behavior on the film thickness. The photocatalyst properties of TiO2 thin films were investigated via photodegradation of two azo dyes, acid blue and acid black, under ultraviolet irradiation. The absorbance spectra indicated that the titanium dioxide thin film with 1000 nm thickness degradation 94 % both acid blue and acid black in 60 min. Also, the increasing film thickness increased degradation at the same time.

In this research, the influence of titanium dioxide nanoparticles on the structural and magnetic properties of high-temperature superconductor Bi1.6Pb0.4Sr2Ca2Cu3O10+θ (Bi-2223) from the Bi-based ceramic system (BSCCO) was studied. In order to investigate the synthesized samples, X-ray diffractometry and magnetic measurements were performed. Based on the magnetic measurements, the superconductivity transition temperature declined with the increase in the nanoparticleschr('39') content. The addition of nanoparticles affected on the hysteresis loop width. Accordingly, the compound containing 0.2 wt.% nanoparticles had the maximum magnetization, hysteresis loop width, and critical current density.

Background and purpose: Malachite green is one of the most widely used dyes in various industries, aquaculture, and fungicides. The residues have adverse effects on environmental and human health and should be removed from the effluent before discharging to the environment. The purpose of this study was to investigate the efficiency of photocatalytic process using halloysite-titanium dioxide nanocomposite in the removal of malachite green from aqueous solutions and the effect of various parameters on the process efficiency. Materials and methods: This experimental study was performed on a laboratory scale in a discontinuous system. In this process, a 15 W (UV-C) lamp of 26 mm diameter and length of 45 cm and a nanocomposite (halloysite-titanium dioxide) were used. The influence of contact time, nanocomposite dose, dye concentration, and pH of the reaction on the removal efficiency was investigated. The properties of the synthesized nanocomposite were determined by sol-gel method using XRD and SEM techniques. The concentration of malachite green was measured using a UV-VIS spectrophotometer at 619 nm. Results: The best photocatalytic dye removal efficiency (91.29%) was seen at 3 mg/l dye concentration, pH= 10, contact time= 90 min, and nanocomposite dose= 0.1 g/l. Conclusion: This study showed that photocatalytic process using nanocomposite (halloysite-titanium dioxide) is efficient in decomposing and removing malachite green.

Interior design, engineering, and the configuration of materials used in photo‏-‏anode systems play ‎key roles in the photovoltaic performance of dye solar cells.‎‏ ‏In this study, the photo-anodes of dye sensitized ‎solar cells were fabricated based on TiO2, ZnO and SnO2 nanoparticles separately using doctor Blade method ‎on the transparent conductive oxide as substrates, then sensitized with N719 dye. Due to the fact that the dye ‎plays the role of photon absorption, different photo‏-‏anode oxides were placed in a N719 dye solution over a ‎different time period.‎‏ ‏Based on current-voltage curve, efficiency parameter, short-circuit current density, ‎open circuit voltage, and fill factor of the cells were obtained. The results of current-voltage characterization ‎indicate that the best time for the N719 dye loading for the TiO2 and SnO2 layers is 20 h and for the ZnO layer ‎is 1 h.‎‎

Introduction: The skin, can be exposed to harmful factors like ultraviolet radiation (UV). Exposure to this physical hazardous agent could be contributed to pigmentation, erythemas, early aging, skin cancer, and DNA damage. The aim of this study, therefore, was to fabricate the polyacrylonitrile (PAN) nanofibers with the UV protection property by the use of various concentrations of titanium dioxide (TiO2) nanoparticles. Material and Methods: The PAN nanofibers (10%wt) containing 0, 1, 5, 10 and 15% wt of TiO2 nanoparticles were produced using electrospinning method. The morphological propertis of nanofibers were studied by scanning electron microscopy (SEM) and the functional groups were investigated by Fourier transform infrared spectrophotometer (FTIR). The UV protection property of nanofibers was studied by measuring UV transmittance as well as calculating UV protection factor (UPF). Results: The results showed that the diameter and morphological characteristics of nanofibers are different at various concentrations of TiO2 and increasing the concentration of TiO2 has resulted to an increase in nanofibers diameter. The analysis of FTIR results showed that TiO2 nanoparticles have been successfully loaded on nanofibers for UV protection purposes. The findings clarified that nanofibers loaded with TiO2 could increase the UV protection property up to 15%. Conclusion: Totally, our findings show the successful fabrication of UV-protective nano webs using TiO2 nanoparticles. the new combination used in nano matcould protect employees from UV radiation.

In order to study the effect of Sodium Selenate, Titanium dioxide and Growth regulator (Hamon Green®) on some physiological traits, yield and oil content of Goldasht cultivar of safflower under drought stress, a split plot experiment was conducted in a randomized complete block design with three replications in Agricultural Research Center of Zabol University (Chah-e-Nime). The main factor included irrigation cut off levels based on the phenological stages of growth in three levels: I1 = control (complete irrigation), I2= irrigation up to stage R2 (flowering) and I3= irrigation up to stage R1 (branching) and sub-factor including control(not spraying), Sodium selenate (2 mM), Titanium dioxide (0.03%), Growth regulator (0.1 L). Drought stress reduced biological yield, seed yield, 1000 seed weight, relative water content and chlorophyll content (SPAD), but seed and biological yield did not differ significantly between two levels of I1 and I2. The highest amounts of catalase(I2+not spraying),and proline, ascorbate and guaiacol peroxidase was obtained from the interaction of stress(I3) and not spraying. The highest amount of soluble carbohydrates was observed in irrigation + Hamon Green® spraying. The treatments applied did not have a significant effect on seed oil percentage. In general, treatment in order to observe water consumption in the production of safflower in Goldsch cultivar seems appropriate.

Currently, the main problem of cities and populated centers is air pollution. Small- and largescale human activities can pollute the environment and leave irreparable effects. One of the most effective ways of reducing air pollution is to control emission sources. Atmospheric pollutants could be controlled by using new methods like applying titanium dioxide. This material can trap air pollutants and decompose them through a photocatalytic process. The use of photocatalytic titanium dioxide in building materials is growing due to the demand for improving air quality in urban and industrial areas. Artificial stones are generally a combination of natural aggregates, industrial gums (resins), and some additives. Since resins are of relatively high costs, polymer materials that are inexpensive and economically cost-effective are replaceable. The method of the present research is a descriptive experiment and applied in terms of purpose This study was conducted in an indoor laboratory. In this shrink model, an artificial stone was fabricated by using high-strength polymer materials and then, titanium dioxide material application in the created synthetic stone for reducing pollutant gases was investigated. The results showed that the synthetic stone made by using polymeric materials and titanium dioxide photocatalyst could reduce over 75% of nitrogen gases in the air. [ABSTRACT FROM AUTHOR]

Among the photocatalysts, Titanium dioxide (TiO2) is mostly used for wastewater treatment. Nevertheless, large band gap, rapid recombination of electron–hole along with difficult separation process limits TiO2 applications in industrial scale. In this study, the photocatalytic activity and separation of TiO2 were improved by combined application of Fe3O4 and graphene oxide. X-ray powder diffraction (XRD), scanning electron microscopy (FESEM), and magnetization measurement (VSM) was utilized to characterize the sample and the photocatalytic degradation of methylene blue under visible light irradiation was evaluated by UV-vis spectrophotometer. The results indicate the successful preparation of purified TiO2/Fe3O4/GO nanocomposite by a two-step sol gel-hydrothermal method. The enhanced photocatalytic activity of nanocomposite is attributed to the simultaneous application of iron oxide and graphene oxide. The maximum photocatalytic decoloration (90%) is achieved within 80 min under lamp irradiation. The superparamagnetism of nanocomposites provided a convenient route for separation of the catalyst from the reaction mixture by an external magnet.

Titanium dioxide is one of the most important minerals with various industrial applications. Extensive research has been carried out to synthesize this material from the past and is also ongoing. At present, despite the high consumption of this material, it does not have internal production and the needs of the country’s industries are being met by import of this product. Considering the country’s richness in terms of having Titanium mines, research has begun to find the conditions for the production of Titanium dioxide from Ilmenite minerals. In this research, Ilmenite concentrate of Kahnouj region in Kerman province was used to obtain Titanium dioxide. This concentrate contains 43% TiO₂ which is a low-grade concentrate. In this project, the production of Titanium dioxide from Ilmenite minerals with two methods of Chloride process and Alkalydecomposition process was investigated. The Alkaly decomposition process involves the steps of decomposition, acid leaching, sediment washing and calcination. Investigating and studying the various Titanium processing methods showed that the Alkally decomposition process has more advantages in terms of moderate operating conditions than other methods. The Titanium dioxide obtained in this study was made by a nano satellite ball mill. The chemical composition of Ilmenite concentrate was investigated by X-ray Fluorescence analysis (XRF). The structural properties and the size of the Titanium dioxide nanoparticles investigated by Furier Transform Infra-Red spectroscopy (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy-Disperssive X-ray spectroscopy (EDX).

This paper studies the structural, optical and ultraviolet photodetection of rutile titanium dioxide nanorods (TiO2). A regular array of relatively vertically aligned TiO2 nanorods has been grown on fluorine doped tin oxide (FTO) coated glass substrate by using one step hydrothermal synthesis method. The morphology and crystal structure were studied by scanning electron microscopy and X- ray diffraction, respectively. Photoluminescence (PL) and diffuse reflectance spectroscopy were used as experimental methods for band gap energy estimation of nanostructures. The room temperature Photoluminescence spectra were measured under two different excitation energies of 4.13 and 3.82 eV. The results indicate the dependence of the PL spectrum to excitation energy. Thus, the band gap energy of nanorods is approximately equal to 3.04 eV and observed in the PL spectrum under 4.13 eV excitation energy. Comparing the applied reported methods for calculating the band gap energy by using diffuse reflectance spectra and Kubelka- Munk method shows that the most relevance to PL data exist with application of equation. The ultraviolet photodetection performance of TiO2 nanorods in Au/TiO2/Au device structure under 365 nm illumination is evaluated by determining resposivity, sensivity and rise and decay tims.

In this research, the influence of titanium dioxide nanoparticles on the structural and magnetic properties of hightemperature superconductor Bi1.6Pb0.4Sr2Ca2Cu3O10+θ (Bi-2223) from the Bi-based ceramic system (BSCCO) was studied. In order to investigate the synthesized samples, X-ray diffractometry and magnetic measurements were performed. Based on the magnetic measurements, the superconductivity transition temperature declined with the increase in the nanoparticles' content. The addition of nanoparticles affected on the hysteresis loop width. Accordingly, the compound containing 0.2 wt.% nanoparticles had the maximum magnetization, hysteresis loop width, and critical current density. [ABSTRACT FROM AUTHOR]

In this research, an antimicrobial bionanocomposites based on carboxymethyl chitosan biopolymer-montmorillonite nanoclay was synthesized in the presence of titanium oxide nanoparticles. Investigation of surface morphology images with scanning electron microscopy (SEM) shows the rough and heterogeneous surface of nanocomposites in comparison with pure carboxymethyl chitosan. The results of the XRD test showed that the diffusion of nanoclay in the presence of TiO2 nanoparticles changed from full sheets to between layers sheets. The addition of TiO2 nanoparticles caused a significant increase (p˂0.05) in turbidity in nanocomposites. The effect of TiO2 nanoparticles on reducing the amount of Gram-positive bacteria of Staphylococcus aureus is more than the effect of TiO2 nanoparticles on reducing the amount of gram-negative bacteria of Escherichia coli. By increasing the percentage of TiO2 nanoparticles, its efficacy in removing colonies of both bacteria is increased. Water solubility and Vapor permeability of nanobiocomposite films decreased with increasing weight percentage of TiO2. The tensile strength of the film containing TiO2 nanoparticles is more than the tensile strength of neat carboxymethyl chitosan film, which is statistically significant (p˂0.05). The study demonstrated the high potential of bionanocomposites in preventing the growth of pathogenic bacteria and showed that such packages could be used to increase the shelf-life of food. [ABSTRACT FROM AUTHOR]

Titanium dioxide nanoparticles (TiO2) are known as a widely used photocatalyst. In order to improve the performance of these nanoparticles, the recombination of the electron-cavity pair must be reduced and the absorption rate of the visible region should be expanded. One way to increase the performance of these nanoparticles is using cerium doped TiO2. In the present study, pure and doped titanium dioxide nanoparticles were made by the electrical discharge method. The effect of cerium dopants on the structural, morphological and optical properties were studied by x-ray diffraction (XRD), scanning electron microscopy (FESEM), diffused reflection spectroscopy (DRS), photoluminescence (PL) and infrared fourier transform (FTIR) spectroscopy analyses. XRD analysis revealed that the size of TiO2 nanocrystals was decreased to 7.7 nm. The FESEM morphology of the samples also showed that the uniformity of the Ce doped TiO2 was decreased. Further, the DRS results indicated that the band gap energy of Ce-TiO2 was decreased to 2.24 eV. The photoluminescence results demonstrated that the intensity of PL was reduced for the Ce-TiO2 sample, which reduced the recombination of the electron-hole coupling and increased the photocatalytic activity in the doped sample.

The cellulose-triazole-TiO2 bionanocomposite synthesized via click reaction and utilized as a nanobioadsorbent for removal of Hg+2 ions from aqueous solution by batch technique. The adsorption parameters such as pH, contact time, adsorbent dosage, temperature, initial metal ions concentration and the regenerability of Cell.Com were investigated. The optimized adsorption conditions were found to be at pH 7, contact time 45 min, adsorbent weight 0.01 g and initial metal ion concentration of 20 ppm at 25 ºC. The Langmuir, Freundlich and Temkin isotherm models were evaluated using adsorption experimental data. The high absorption capacity obtained from the Langmuir equation (Hg+2 = 133.3 mg g-1) is related to the synergistic effect of TiO2, triazole ring and cellulose moieties in the structure of Cell.Com. Among the pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models, the experimental data was best fitted with the pseudo-second order model. Thermodynamic parameters indicated a spontaneous and endothermic adsorption process. The Cell.Com adsorption behavior represents that a monolayer chemical adsorption is the rate-determining step. The adsorption-desorption process for Cell.Com was performed in HCl solution at least 3 cycles without significant loss of the adsorption capability.

Abstract: In this research, the composite of TiO2/Zeolite as a cheap and effective photocatalyst was prepared for the removal of methyl orange dye in water solution. At first, TiO2 solution was successfully synthesized and then combined with appropriate amount of Clinopatilolite zeolite. The prepared samples were calcined at different temperatures. The synthesized photocatalysts were characterized by, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and Fourier transform infrared (FTIR). The effect of the calcination temperatures and the amount of zeolite in composite of the as-synthesized photocatalysts on crystal structure, morphology and photocatalytic degradation of methyl orange dye solution were studied. The results of the experiments showed that combining of zeolite with TiO2 induced the enhancement of photocatalytic activity and optimal zeolite content was obtained about 0.1 g (0.33 wt.% ). Also calcination temperature has a great influence on the photocatalytic activity of the synthesized samples. The optimal calcination temperature was obtained 300⁰C. The composite of TiO2/Zeolite powders obtained from the optimum condition showed uniform spherical shape, anatase crystalline structure and few agglomerates. The methyl orange was removed more than 96% within 60 min of the process with optimum calcinations temperature and zeolite content.

In this research, photocatalytic degradation method for COD(CHEMICAL OXYGEN DEMAND Value) removal has been introduced to treatment of petrochemical industries wastewater as an adaptable method and effective parameters in the process performance have been investigated. Therewith, by using commercial photocatalyst of titanium dioxide and empirical measurement of COD parameter, decrease percentage of this parameter of photocatalytic process during 90 minutes investigated via DOE&ANN method. To carry out experiments,A photocatalytic reactor with agitator used which UV-C lamps submerged within photocatalyst solution in the wastewater sample. Results of experiments at optimized conditions indicated that two models is in a good agreement with the consequences. These results demonstrated that photocatalyst concentration increase in the neutral pH state to optimized amount of 0.84 grams per liter under unlimited conditions and 2 grams per liter under limited conditions, causes removal increase of COD to 93 and 77 percent, respectively(from 180 to 90 and 294 respectively).

In the present study, alkali roasting and oxalic acid leaching were used to extract titanium dioxide from ilmenite, and the effect of ethanol and ascorbic acid on the purity and recovery of titanium dioxide was investigated. In this research, ilmenite was alkali roasted with sodium carbonate for 4 hours at 900˚C. Then, the roasted ilmenite was leached with distilled water for 1 hour at room temperature. Finally, leaching with a mixture of 0.47M oxalic acid and different amounts of ascorbic acid and ethanol was performed at 65˚C. The results showed that using ethanol caused an increase in the amount of recovery and ascorbic acid increased the purity of the extracted titanium dioxide; also, the presence of these two factors at the same time simultaneously increased the amount of purity and recovery of the final product. Eventually, by choosing 0.47M oxalic acid, 0.005M ascorbic acid, and 48% ethanol as the appropriate conditions for leaching media and increasing the leaching time and temperature to 16 hours and 80˚C, it was possible to get titanium dioxide purities which were as high as 93.3% and 90.9%, respectively.

Background: Titanium dioxide (TiO2) nanoparticles (NPs) activated by ultraviolent light (UV) have been recently proposed as a nano-photosensitizer (PS) for cancer therapy. However, because adverse effects of UV light, other dopped-TiO2 NPs with ability of activation by safe light sources, such as visible light, have been recommended for photodynamic therapy (PDT) purposes. The aim of this study is to evaluate effects of photodynamic N-TiO2 NPs in MCF-7 cell line as human epithelial breast cancer cell line. Methods: MCF-7 cells were treated with different concentrations of N-TiO2 NPs and a visible light source was used for their photocatalytic activation. Trypan blue staining was performed to investigate the rate of cell viability and cell growth at 24h and 48h upon irradiation. Acridine Orange/Ethidium Bromide (AO/EtBr) staining and deoxyribonucleic acid (DNA)-laddering assay were used for detecting the mode of cell death. Results: Treatment of MCF-7 cells with N-TiO2 NPs, up to 100 µg/ml was inert and did not significantly affect growth and viability. However, with the increasing at concentrations of NP, the rate of cell death increased considerably upon visible-light irradiation. The AO/EtBr double staining and DNA-ladder assay showed that the mode of cell death induced by photodynamic N-TiO2 NPs is mostly through apoptosis. Conclusion: N-TiO2 NPs in conjugation with visible-light may be proposed as a safe approach for PDT of breast cancer cells.

Background and purpose: Photocatalysis process with TiO2 is a well-known method for removal of pollutants from water. However, the small particle size of TiO2, and therefore difficulty in its separation after treatment impede its commercialization. The aim of this study was to synthetize the Fe3O4@SiO2@TiO2 magnetic nanoparticles (NPs) and evaluation of its efficiency in removal of metronidazole (MNZ) from aqueous solutions. Materials and methods: The NPs were synthetized via sol-gel method, and characterized using SEM, XRD, VSM, and BET analysis. Then, the effect of operational parameters, including catalyst dosage, pH, and initial concentration of MNZ on removal efficiency were examined. The order of reaction and kinetic model, as well as the reusability potential of the catalyst were all investigated in the optimum run. Finally, comparison was made between the adsorption, direct photolysis, application of commercial Degussa P25 TiO2 (p25), and Fe3O4@SiO2@TiO2 NPs. Results: The so-synthesized catalyst showed good superparamagnetic properties. The optimum conditions for the MNZ removal were pH=8, the catalyst dosage=1.5 g/L, and initial concentration of MNZ=40 mg/L under 180 min UV irradiation time. The kinetic study revealed that the photocatalytic degradation of MNZ followed the pseudo- first order (R2= 0.9912) and the Langmuir-Hinshelwood model (R2= 0.9976). Conclusion: According to the results, the Fe3O4@SiO2@TiO2 NPs were almost as effective as commercial catalyst Degussa P25 TiO2 in removal of MNZ (P> 0.05). Due to the simple separation with external magnetic field and reusability potential, Fe3O4@SiO2@TiO2 NPs can be considered as a suitable alternative for Degussa P25 TiO2.

Background and Objective: Triclosan is one of the substances as anti-microbial that is used in many of these pharmaceutical products. This compound can affect human such as reduction of thyroid hormone levels, antibiotic resistant, and increasing skin cancer. This study evaluated the performance nanophotocatalysis process UV/Xe/TiO2-GO on triclosan removal from aqueous solutions. Materials and Methods: Synthesis of TiO2@GO and its structure was analyzed by SEM, EDX and FTIR. The effects of pollutant concentration, catalyst dosage, and contact time on the removal of Triclosan were studied by DOE software according to response surface methodology. Analysis of variance test was considered for the influence of parameters. Optimum process condition was determined by desirability factor. Results: Optimum conditions regarding concentration of pollutant, contact time, and catalyst dosage were determined as 0.205 g/L, 14.898 min, and 0.487 mg/L, respectively. Maximum removal efficiency in optimum condition was 97.542 percent. The catalyst dosage was the most effective parameter in removal of Triclosan. Conclusion: Using of TiO2@GO and xenon lamp had acceptable efficiency for the removal of Triclosan. The use of Xenon lamps alone was economically affordable.

In the present research, the steam generation performances of nanofluids containing titanium dioxide have experimentally been examined. For this purpose, a solar simulator with a xenon lamp as the radiation source, and a pyranometer as a light intensity measuring device are used. Then, the water based-nanofluids in five nanoparticle mass fractions of 0.001, 0.002, 0.004, 0.04, and 0.08% exposed to the light intensity of 3.5Suns (3.5 kW/m2) were investigated to compare their evaporation performances with water (H2O). Finally, the effects of the solar power intensity on the steam generation were examined. The results showed that the titanium dioxide nanostructures are more efficient to directly absorb the solar energy than the water so that the maximum total evaporation efficiency of 77.4% and 54% were obtained at 3.5 kW.m-2 for nanofluid and water, respectively. Furthermore, it was found that light absorption increases as the nanofluid mass fraction increases. Also, increasing the light intensity from 1.5 to 3.5 kW.m-2 enhances the thermal efficiency, while it reduces the evaporation efficiency. [ABSTRACT FROM AUTHOR]

Utilization of paper as packaging material and developing applied technological program on paper-based substrate are drastically dependent to control of cellulosic fiber hydrophilicity and to enhancement of its hydrophobic properties. Then this work carried out with the aim of developing hydrophobic surface on cellulosic fiber with layer by layer (LBL) method while keeping and enhancing the properties of paper network. The deposition was implemented by titanium dioxide nanoparticles and poly acrylic acid as cationic and anionic layer respectively on the fibers of unbleached hardwood Kraft pulp and using Zycosil and fluoroalkyl silane on the last layer. The hand-sheets were then made by this modified fiber. The contact angle and roughness were measured to evaluate the effect of layers on hydrophobicity. The results indicated that roughness increased with the number of layers. The instant contact angle was also increased with the number of layers and reached approximately to 110 degree at 7th layer. The dynamic contact angles dropped more lately with increasing the number of layers. The fluorosilane deposition as 8th layer in comparison with Zycosil showed more effect on surface energy reduction. The instant contact angle of Zycosil treated paper was measured 125 degree which dropped significantly to 48 degree after 30 seconds. However, fluorosilane modified paper exhibited contact angle of 140 degree at the same time. In addition, the presence of titanium dioxide nanoparticles on the surface of fiber was demonstrated by scanning electron microscopy (SEM) of paper surface.

TiO2/MWCNT nanocomposite thin films containing different percentages of multi-walled carbon nanotubes were coated on fluorinated tin oxide substrates by sol-gel dip coating method. Results of X-ray diffraction analysis indicated that the crystal structure of the coatings was anatase TiO2. It was also understood that the size of crystallites reduced with CNT but structural properties and equilibrium phase remain intact. Field emission scanning electron microscope images showed that CNTs dispersed uniformly among 45 nm spherical TiO2 particles of close relations. These images also showed that CNT promoted cracks on the coated surface. Results of the UV-Vis spectroscopy showed that the visible light range adsorption increased with CNT and the absorption edge did not significantly differ with the pure TiO2 layers.. Results of the photoluminescence spectroscopy revealed that the presence of CNT could reduce the pair electron–electron holes recombination which is considered totally undesirable.

Introduction: Textile industries, due to a high volume of wastewater and harmful environmental factors such as a variety of dyes, are significant industries in industrial wastewaters treatment. So, the aim of this study was to examine the efficiency of dye removal from the textile industry wastewater using the titanium dioxide photocatalytic process under UV-LED light irradiation (UV-LED/TiO2) in the treatment of the Nakh Rang factory wastewater in Hamadan City, Iran. Methods: In this experimental study, in every experiment, 100 mL sample was placed inside the LED reactor to expose to the UV light and TiO2. The effects of some parameters such as contact time, pH and dosage of TiO2 were examined, and decomposition kinetics and the synergistic effects were also determined for each process. Results: The results of the experiments showed that the UV-LED/TiO2 process can remove the dye from textile wastewater with the efficiency of 80.23% and can also remove the chemical oxygen demand (COD) with the efficiency of 64.75% under the optimum conditions and during 120 minutes. Also, the reaction of dye decomposition in this wastewater was a first-order kinetic function. Conclusion: The results of this study show that the UV-LED/TiO2 can be used effectively to remove the dye and reduce the COD of the textile industry wastewater under optimal operating conditions.

Introduction: Styrene monomer is a volatile organic compound that has many applications particularly in plastic, rubber and paint industries. According to the harmful effects of these compounds on human and environment, reducing and controling of them seem necessary. Therefore, in this study removal of styrene was investigated using photocatalytic process of titanium dioxide nanoparticles stabilized on ZSM-5. Methods: After stabilization of titanium dioxide nanoparticles on ZSM-5 zeolite, BET, SEM and XRD analysis were used to determine the characteristics of nanoparticles. Experiments were conducted at ambient temperature in laboratory scale. Concentration of produced styrene in the experiments was 50 and 300 ppm, and input flow rate was 1 l/min. Results: images and spectra obtained through XRD and SEM-EDAX showed that nano-catalysts are well- stabilized. The results showed that by increasing of input concentration of styrene from 50 to 300 ppm, photocatalytic removal efficiency are reduced. Also, adsorption capacity of the catalyst bed in concentrations of 50 and 300 ppm was calculated 16.3 and19.4 mg/gr of adsorbent respectively. Conclusion: The results show that the use of hybrid bed can increase the removal efficiency of contaminants. And due to low cost of application of these systems compared to conventional methods, it is recommended that more comprehensive studies to be done regarding the optimization of the parameters affecting the process of photocatalytic removal.

Titanium dioxide nanoparticles (TiO2) are known as a widely used photocatalyst. In order to improve the performance of these nanoparticles, the recombination of the electron-cavity pair must be reduced and the absorption rate of the visible region should be expanded. One way to increase the performance of these nanoparticles is using cerium doped TiO2. In the present study, pure and doped titanium dioxide nanoparticles were made by the electrical discharge method. The effect of cerium dopants on the structural, morphological and optical properties were studied by x-ray diffraction (XRD), scanning electron microscopy (FESEM), diffused reflection spectroscopy (DRS), photoluminescence (PL) and infrared fourier transform (FTIR) spectroscopy analyses. XRD analysis revealed that the size of TiO2 nanocrystals was decreased to 7.7 nm. The FESEM morphology of the samples also showed that the uniformity of the Ce doped TiO2 was decreased. Further, the DRS results indicated that the band gap energy of Ce-TiO2 was decreased to 2.24 eV. The photoluminescence results demonstrated that the intensity of PL was reduced for the Ce-TiO2 sample, which reduced the recombination of the electron-hole coupling and increased the photocatalytic activity in the doped sample. [ABSTRACT FROM AUTHOR]

Background: Today, titanium dioxide (TiO2) nanoparticles present extensive therapeutic applications. The present study was conducted to investigate the cytotoxicity of TiO2 on colon cancer cell line (HT29), and analyze the expression of caspase-3 and 9 genes. Materials and Methods: The present experimental study used the MTT assay to examine the cytotoxicity of 3.125, 6.25, 12.5, 25, 50 and 100 μg/ml concentrations of TiO2 nanoparticles on cell line HT29. After the treatment of HT29 cells with IC50 concentration of TiO2, the gene expression levels of caspase-3 and caspase-9 were investigated and compared with the reference gene of GAPDH using real time PCR. DAPI staining and flow cytometry were ultimately used to confirm apoptosis in HT29 cells. Results: The treatment of HT29 cells with different concentrations of TiO2 showed that TiO2 nanoparticles at 50 and 100 μg/ml concentrations present the highest cytotoxicity, which was statistically significant (P<0.05). Moreover, the expression of caspase-3 gene was found to be significantly upregulated by 2.0±69.13 (P<0.001) and that of caspase-9 gene by 3.0±46.29 (P<0.001) in HT29 cell lines treated with TiO2 nanoparticles for 24 hours. The results of DAPI staining and flow cytometry also confirmed apoptosis in HT29 cells. Conclusion: According to the obtained results, TiO2 nanoparticles can be recommended as prospective medicinal candidates for pharmaceutical purposes, although further studies are required in this field. [ABSTRACT FROM AUTHOR]

The purpose of this research is preparation of titanium dioxide nanotubes modified with nickel nanoparticles as a photocatalyst sensitive to visible light. For this purpose, at first, titanium dioxide nanotubes was synthesized on the surface of titanium using electrochemical anodizing; then by immersion of prepared nanotubes in an aqueous solution of nickel nitrate, film of nickel nanoparticles on the surface of the nanotubes were produced. Morphology and crystal structure of the resulting films were studied using scanning electron microscopy and X-ray diffraction. To determine the composition and confirmation the presence of nickel nanoparticles, we used from energy dispersive X-ray spectroscopy (EDX). Then, photocatalysts efficiency of obtained nano-catalysts for the removal of methylene blue dye was performed. Photocatalytic test results showed that produced nanocatalysts have good activity.

The potential entry of nanomaterials into the water ecosystems increased following their increasing use. In addition to the direct effects of nanomaterials on aquatic organisms, they also affect the toxicity of other pollutants on aquatic organisms. This study assessed the presence of titanium dioxide nanoparticles (nTiO2) in water on acute toxicity of silver nanoparticles (AgNPs) on zebra fish (Danio rerio). After preliminary tests, we simultaneously exposed the fish for 96 h to different concentrations of each of these nanoparticles so that, in each of the treatments, the concentrations of nTiO2 were ten times the concentration of AgNPs. The results showed that the presence of nTiO2 in water decreased the acute toxicity of AgNPs to more than three times in the zebra fish. The median lethal concentrations of AgNPs increased from 0.014 (in the absence of nTiO2) to 0.044 (in the presence of nTiO2). The reduction in toxicity of AgNps in the presence of TiO2 nanoparticles in this study possibly happened due to decreased bioavailability of AgNPs by binding to the nTiO2 and its deposition in water media.

With various features such as strong oxidation, biocompatibility and acceptable mechanical properties, titanium dioxide (TiO2) is among the materials that are frequently used in biological and medical applications. Nowadays, with the aim of increasing the efficiency of titanium dioxide and practical use of this material, doping it with elements such as silver, zinc and iron has been favored. In this study, Ag-TiO2 and ZnO-TiO2 nanoparticles were prepared by the sol–gel method and were evaluated and compared.In order to identify the present phases in the structure, X-ray diffraction analysis was used. Also for the characterization of the nanoparticles, Ultraviolet–visible spectroscopy (UV-Vis), Energy-dispersive X-ray spectroscopy (EDS), Field Emission Scanning Electron Microscope (FESEM) and Zeta Potential were used. Inaddition, the antibacterial activities of nanoparticles were investigated and compared. The results showed that sol-gel method could successfully produce nanoparticles of Ag-TiO2 and ZnO-TiO2 with the expected combination. The investigation of antibacterial properties of these particles revealed that at lower inhibitory concentrations, Ag-TiO2 composition has a higher antibacterial activity than ZnO-TiO2 one.

In this research, a titanium dioxide thin film with average particles size of 8 nm was prepared on glass surface and then it's crystalline and optic properties before and after calcinations was investigated. Low angle XRD analyses showed that prepared thin film has mesoporous structured prior to calcination and a further increase in the meso-scale order has been made by calcination. Low angle XRD analyses revealed three peaks related to hexagonal symmetry before and after calcination. Lattice constant of the prepared titanium dioxide before and after calcination, using miller indices of (100) crystal plane calculated to be 147.57 and 143.47 Å, respectively. Transmission spectra of titanium dioxide coating exhibit a significant blue shift in absorption edge and increasing of its transparency after calcination. Indirect band gap of prepared coating estimated from Uv-vis spectra to be 3.69 eV and refractive index of the film and its porosity percentage was calculated to be 1.54 and 67%, respectively.

Background and Objectives: Titanium dioxide (TiO2) is a nanoparticle, which is widely used in various fields as a healthcare composition to control microorganisms. The small size of this nanoparticle and its chemical composition and high reactivity, have potential risks for human health and the environment. Due to the abundant use of this nanoparticle over the recent centuries, the effect of the material on mouse intestine, was studied in this study. Methods: In this research, 12 male mice were randomly divided into 3 groups of 4 each. The first group as the control-sham, received HPMC at a dose of 1 mL; the second group received 1ml TiO2 and 10mg/kg HPMC; and the third group received 1ml TiO2 and 100ml/kg HPMC, intraperitoneally. After 35 days of treatment, the mice were weighed, and after anesthesia, their intestines were removed and studied by light microscopy after H&E staining. Data were analyzed by one-way ANOVA and Tukey test at the probability of p

Dye-sensitized solar cell (DSSC) using natural Pomegranate juice as dye-sensitizeris fabricated and characterized. DSSCS consist of a working electrode, a redox electrolyte containing iodide and tri-iodide ions and a counter electrode. A nanocrystalline TiO2 semiconductor with a wide band-gap coated with a monolayer dye-sensitizer is used as working electrode. The effect of titanium dioxide (TiO2) nanoparticle size on efficiency of the DSSC based Pomegranate juice as a sensitizer is studied. For monolayer structure, we used two sizes of TiO2 nanoparticle (25 nm and 100 nm) and a mixture of these two sizes. The highest efficiency of 0.61% was obtained with mixture of 25 and 100 nm TiO2 nano-particles in working electrode. For double-layer structure, we used 100 and 400 nm size TiO2 particles as light-scattering. The best efficiency was obtained using 400 nm TiO2 as light-scattering particles.

Background and purpose: Photocatalysis process with TiO2 is a well-known method for removal of pollutants from water. However, the small particle size of TiO2, and therefore difficulty in its separation after treatment impede its commercialization. The aim of this study was to synthetize the Fe3O4@SiO2@TiO2 magnetic nanoparticles (NPs) and evaluation of its efficiency in removal of metronidazole (MNZ) from aqueous solutions. Materials and methods: The NPs were synthetized via sol-gel method, and characterized using SEM, XRD, VSM, and BET analysis. Then, the effect of operational parameters, including catalyst dosage, pH, and initial concentration of MNZ on removal efficiency were examined. The order of reaction and kinetic model, as well as the reusability potential of the catalyst were all investigated in the optimum run. Finally, comparison was made between the adsorption, direct photolysis, application of commercial Degussa P25 TiO2 (p25), and Fe3O4@SiO2@TiO2 NPs. Results: The so-synthesized catalyst showed good superparamagnetic properties. The optimum conditions for the MNZ removal were pH=8, the catalyst dosage=1.5 g/L, and initial concentration of MNZ=40 mg/L under 180 min UV irradiation time. The kinetic study revealed that the photocatalytic degradation of MNZ followed the pseudo- first order (R2= 0.9912) and the Langmuir-Hinshelwood model (R2= 0.9976). Conclusion: According to the results, the Fe3O4@SiO2@TiO2 NPs were almost as effective as commercial catalyst Degussa P25 TiO2 in removal of MNZ (P> 0.05). Due to the simple separation with external magnetic field and reusability potential, Fe3O4@SiO2@TiO2 NPs can be considered as a suitable alternative for Degussa P25 TiO2. [ABSTRACT FROM AUTHOR]

In the present study, alkali roasting and oxalic acid leaching were used to extract titanium dioxide from ilmenite, and the effect of ethanol and ascorbic acid on the purity and recovery of titanium dioxide was investigated. In this research, ilmenite was alkali roasted with sodium carbonate for 4 hours at 900˚C. Then, the roasted ilmenite was leached with distilled water for 1 hour at room temperature. Finally, leaching with a mixture of 0.47M oxalic acid and different amounts of ascorbic acid and ethanol was performed at 65˚C. The results showed that using ethanol caused an increase in the amount of recovery and ascorbic acid increased the purity of the extracted titanium dioxide; also, the presence of these two factors at the same time simultaneously increased the amount of purity and recovery of the final product. Eventually, by choosing 0.47M oxalic acid, 0.005M ascorbic acid, and 48% ethanol as the appropriate conditions for leaching media and increasing the leaching time and temperature to 16 hours and 80˚C, it was possible to get titanium dioxide purities which were as high as 93.3% and 90.9%, respectively. [ABSTRACT FROM AUTHOR]

Background and Objective: Triclosan is one of the substances as antimicrobial that is used in many of these pharmaceutical products. This compound can affect human such as reduction of thyroid hormone levels, antibiotic resistant, and increasing skin cancer. This study evaluated the performance nanophotocatalysis process UV/Xe/TiO2-GO on triclosan removal from aqueous solutions. Materials and Methods: Synthesis of TiO2@GO and its structure was analyzed by SEM, EDX and FTIR. The effects of pollutant concentration, catalyst dosage, and contact time on the removal of Triclosan were studied by DOE software according to response surface methodology. Analysis of variance test was considered for the influence of parameters. Optimum process condition was determined by desirability factor. Results: Optimum conditions regarding concentration of pollutant, contact time, and catalyst dosage were determined as 0.205 g/L, 14.898 min, and 0.487 mg/L, respectively. Maximum removal efficiency in optimum condition was 97.542 percent. The catalyst dosage was the most effective parameter in removal of Triclosan. Conclusion: Using of TiO2@GO and xenon lamp had acceptable efficiency for the removal of Triclosan. The use of Xenon lamps alone was economically affordable. [ABSTRACT FROM AUTHOR]

TiO2/MWCNT nanocomposite thin films containing different percentages of multi-walled carbon nanotubes were coated on fluorinated tin oxide substrates by sol-gel dip coating method. Results of X-ray diffraction analysis indicated that the crystal structure of the coatings was anatase TiO2. It was also understood that the size of crystallites reduced with CNT but structural properties and equilibrium phase remain intact. Field emission scanning electron microscope images showed that CNTs dispersed uniformly among 45 nm spherical TiO2 particles of close relations. These images also showed that CNT promoted cracks on the coated surface. Results of the UV-Vis spectroscopy showed that the visible light range adsorptionincreased with CNT and the absorption edge did not significantly differ with the pure TiO2 layers.. Results of the photoluminescence spectroscopy revealed that the presence of CNT could reduce the pair electron–electron holes recombination which is considered totally undesirable. [ABSTRACT FROM AUTHOR]

Introduction: Styrene monomer is a volatile organic compound that has many applications particularly in plastic, rubber and paint industries. According to the harmful effects of these compounds on human and environment, reducing and controlling of them seem necessary. Therefore, in this study removal of styrene was investigated using the photocatalytic process of titanium dioxide nanoparticles stabilized on ZSM-5. Methods: After stabilization of titanium dioxide nanoparticles on ZSM-5 zeolite, Brunaueremmett-Teller (BET), scanning electron microscopy (SEM) and X-ray diffractometry (XRD) analyses were used to determine the characteristics of nanoparticles. Experiments were conducted at ambient temperature in a laboratory scale. Concentrations of the produced styrene in the experiments were 50 and 300 ppm, and the input flow rate was 1 l/min. Results: The images and spectra obtained through XRD and SEM-EDAX showed that nano-catalysts are well-stabilized. The results showed that by increasing the input concentration of styrene from 50 to 300 ppm, the photocatalytic removal efficiency was reduced. Also, adsorption capacities of the catalyst bed in concentrations of 50 and 300 ppm were calculated 16.3 and 19.4 mg/g of adsorbent, respectively. Conclusions: The results show that the use of hybrid bed can increase the removal efficiency of contaminants. Also, due to low cost of application of these systems compared to conventional methods, it is recommended that more comprehensive studies be conducted regarding the optimization of the parameters affecting the process of photocatalytic removal. [ABSTRACT FROM AUTHOR]

ackgrounds and Objective: Titanium dioxide (TiO2) is a potent photosensitizer in photodynamic therapy (PDT) and is activated upon ultraviolet (UV) irradiation.The aim of this study was the assessment of the effect of nitrogen -nano doped of titanium dioxide in human A-375 melanoma cancer cell line. Materials and Methods: N-TiO2 nanoparticles were prepared by mechanical mixing of urea with TiO2 powder in a 4:1 weight ratio. A-375 cells were treated with different concentrations of N-TiO2 for various time intervals in the presence or absence of visible light. The growth and viability of A-375 cells were determined by means of trypan blue exclusion test and MTT assay, respectively. Acridine orange/Ethidium bromide double staining and DNA gel electrophoresis were applied to determine apoptosis. Results: The results showed that visible light activated N-TiO2 could induce growth inhibition in a dose (0.01-100 μg/ml ) and time dependent manner. In concentration of 0.5 μg/ml a significant difference was observed between the treated and the control samples.Decrease in viability was observed in 100 μg/ml concentration and the results of fluorescent microscopy showed DNA fragmentation due to apoptotic cell death[G1] at this concentration. Conclusion: Based on the anti-cancer effects of N-TiO2 on A-375 cells, further evaluation of these nanoparticles as a new photosensitizer in photocatalytic therapy of skin cancer can be proposed. [ABSTRACT FROM AUTHOR]

Background: Nowadays, nanomaterials are used in daily life extensively. One of the most common of these materials is nano titanium dioxide (TiO2) which is used to purify the air and also sunscreens, shampoos and other hygienic products. Although nano-particles are useful, can also have potential hazards. The aim of this study is to evaluate the effects of TiO2 on lung tissue in rabbits.Methods: We divided 18 male rabbits into three groups randomly. The first group recei-ved 50 µl of TiO2 with dose of 50 mg/kg by intratracheal instillation. The second group received 50 µl of TiO2 with dose of 100 mg/kg and the third group received 50 µl of nor-mal saline by the same route. Chest X-rays were taken from all rabbits before injection and on days of 10, 17 and 24 after injection. Twenty four days after injection, rabbits anesthetized and histopathological assays, blood samples and biochemical factors were evaluated.Results: Radiographic assays showed a progressive pulmonary fibrosis in rabbits recei-ved TiO2 rather than the control group and this lesion developed to maximum at 24th day of the experiment. We also showed pulmonary emphysema and inflammation in histo-pathologycal study of groups treated with TiO2. Moreover, we observed a significant increase in the amount of liver enzymes, white blood cells and hematocrit in TiO2 treat-ed groups compared to control group (P≤0.05). There were no significant differences between plasma levels of creatinine in different groups (P>0.05).Conclusion: Results showed that nanotitanium dioxide particles can lead to pulmonary fibrosis and inflammation and also increasing liver enzymes and inflammatory cells.

Silica nanoparticles were modified with titanium tetraisopropoxide (TTIP) via atwo-step sol-gel route. The modified silica nanoparticles were characterized using FTIR spectroscopy, thermal gravimetric analysis (TGA) and EDAX elemental analysis. Photocatalytic activity of the modified nanocomposites was evaluated by photo-activated degradation of Rhodamine B (Rh.B) dyestuff, as a colorant model, in distilled water. Reduction in Rh.B concentration in aqueous solution was evaluated by UV-visible spectroscopy and with the aid of visual observations. The FTIR spectroscopy results confirmed the formation of Ti-O-Si chemical bond on the surfaceof silica nanoparticles. TGA test results showed that the weight loss of the modified sample is due to deterioration of the alkoxy groups of the SiO2 surface. According to the results of EDAX elemental analysis, the presence of carbon and titanium in the structure of the modified samples and also reduction in oxygen levels are attributed to the chemical interactions due to surface chemical modification. Carbon detection in the composition can be attributed to the presence of isopropoxide in titanium tetraisopropoxide compound. The results also revealed that, with TiO2 grafting on the silica nanoparticles surface, absorption in UV region is increased and that the silica nanoparticles modified with titanate compound show photocatalytic characteristics and degradation ability of Rh.B dyestuff under UV light irradiation. It became also evident that the photocatalytic activity of the modified nanoparticles is less than TiO2 nanoparticles. However, by inclusion of modified silica nanoparticles into the polymeric coating, the photocatalytic properties of the coating can be established. Although modified silica nanoparticles have less photocatalytic activity compared to TiO2 nanoparticles, but they cause less damage to the polymer matrix.