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Research subject: In the present study, titanium dioxide/silver nanocomposites (TiO₂/Ag) were synthesized by sol-gel method and their performance for photocatalytic removal of metribuzin was compared with commercial TiO₂ catalysts P25 Degussa.
Research approach: The synthesized nanocomposites were evaluated using X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray analysis (EDX). The effect of operating parameters including reaction time (0-240 minutes), pH (9-4), catalyst dose (0.005-0.015 g), temperature (10-60 ºC), visible light and UV light radiation, concentration Initial metribuzin (10-25 mg/L), the catalyst effect in the dark, and the amount of silver in TiO₂/Ag nanocomposites (0.10-7% by weight) were investigated on the photocatalytic removal of metribuzin from artificial and real aqueous solutions.
Main results: Laboratory investigations showed that TiO₂/Ag nanocomposite containing 10% by weight of silver, reaction time of 120 minutes, pH equal to 6, catalyst mass of 0.013 g, and initial concentration of 10 mg/L metribuzin are the best properties to maximize the removal of metribuzin in the presence of UV light. The obtained results showed that the synthesized TiO₂/Ag nanocomposite has a higher potential in the degradation of herbicides compared to the commercial TiO₂ nano-catalyst. In addition, the proposed method was used to remove metribuzin injected into the water of the Karun and Zohreh rivers and the wastewater of the sugarcane factory under optimal conditions, and successful results were obtained. Also, the results of using and regenerating the titanium dioxide/silver catalyst three times to remove metribuzin show the high efficiency of this photocatalyst in removing metribuzin from water samples. Comparing the methods available in the literature for the removal of metribuzin with the present method showed that the proposed method is better or comparable to the reported methods.

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Backgrounds: This study aimed to assess antibacterial properties of Artemisia scoparia, Titanium dioxide nanoparticles, and their synergistic effect on clinical isolates of Klebsiella pneumonia.
Materials & Methods: In this experimental study, 30 isolates of K. pneumonia were collected from patients’ sputum in the microbiology lab of Masih Daneshvari hospital during 3 months. Then biochemical tests were performed for strain confirming. Moreover, genomic DNA was extracted from all the isolates, and hly gene was detected in the isolates via PCR method. The susceptibility of the isolates to 10 antibiotics was evaluated by the disk diffusion method. Then minimum inhibitory concentration (MIC) of all components (Artemisia extract, TiO2, and their combination) was assessed using the microdilution method against the isolates.
Findings: The results indicated that simultaneous use of hydro-alcoholic extract of A. scoparia and titanium dioxide nanoparticles exhibited a significant synergistic antibacterial effect on 25 clinical isolates in comparison with the use of extract or nanoparticles alone.
Conclusion: It seems that simultaneous use of Artemisia herbal extracts and nanoparticles is beneficial in increasing their antibacterial effect and may decrease antibiotics consumption.

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Aims: In recent years, awareness of how urban surfaces can improve the microclimate has grown. Meanwhile, the challenge of using cool materials in urban spaces to change the microclimate is significant. Because urban surfaces are made up of two types of vertical surfaces (urban facades) and horizontal surfaces (pavements), each of which has a different impact based on where it is set.

Methods: This research investigates the cooling effect of titanium dioxide (TiO2)-based photocatalytic self-cleaning material (P-S-TiO2) in an urban square. Materials and methods: This study experimentally studied the evaluation of these materials on horizontal and vertical urban surfaces using ENVI-met software in the space of an urban square, a topic unexplored in earlier research.

Findings: The findings show that when these materials were used in the square's pavement, the air temperature of the urban space of the square at the height of 1.5 meters decreased by about 0.6°C because the square's pavement is about 16°C cooler. Meanwhile, the simulation results showed that if these materials are used in the urban facades of the square, there will be no noticeable change in the air temperature.

Conclusion: The conclusion of this research will increase awareness of how to use P-S-TiO2 on both vertical and horizontal surfaces. In other words, using these materials on horizontal surfaces benefits the urban microclimate. Improving the urban microclimate increases the quality of the urban space of JOLFA neighborhood square.

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Abstract- In this study, mechanical and thermal properties of nanocomposites based on polypropylene/ linear low density polyethylene/ nano titanium dioxide (PP/LLDPE/Tio2) were studied. The samples were produced using a co-rotating twin screw extruder including 0,2,4 Wt.% of nano particles, 20,40,60 Wt.% of LLDPE and styrene-ethylene-butylene-styrene(SEBS) as comptabilizer. Tensile properties (modulus, tensile strength and elongation at break), impact resistance and thermal properties (meltingand crystallization temperatures) were evaluated. The results showed that modulus was increased by 9% with addition of nano particles in comparison to PP/LLDPE. In addition, impact resistance was increased and tensile strength and elongation at break were decreased. Melting and crystallization temperatures of PP were increased less or more while, these temperatures for LLDPE did not show meaningful differences.

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In this study, emulsion films based on pectin were prepared by the casting method, and the effect of titanium dioxide (TiO2) nanoparticles and carnauba wax on the mechanical and the antimicrobial properties of films were studied. The results showed that water vapor permeability was decreased by increasing of nanoparticles. Mechanical tests showed that the tensile strength (TS) of films was lower than control film duo to adding wax carnauba. But TiO2 increased the TS of films. The highest TS was observed in the films incorporating 1% TiO2. Carnauba wax increased the elasticity of films, but TiO2 reduced this parameter. Results showed that both TiO2 and carnauba wax decreased the transparency of films. In the case of the yellow index, carnauba wax increased and TiO2 decreased the “b” value. Antimicrobial test results showed that the inhibitory effect of films against Escherichia coli was increased by the TiO2 and 3% TiO2 had the highest inhibitory effect. Also, the films were studied in terms of morphology and distribution of nanoparticles using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that by increasing the nanoparticle concentration, agglomeration of nanoparticles was increased.

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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.
 

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In this study, biodegradable packaging based on gelatin biopolymer (at a concentration of 3% w/w) containing nanoparticles of titanium dioxide (at a concentration of 1% w/w) and saffron extract (at a concentration of 2% v) by evaporation method was synthesized. In this study, physical properties (thickness, transparency, moisture content, solubility and water vapor permeability), mechanical, antimicrobial and antioxidant properties, structural and transparency properties of films were investigated. After analyzing the data, the results showed that the effect of saffron extract and titanium dioxide nanoparticles on all the studied properties was significant (P <0.05). Addition of titanium dioxide nanoparticles and saffron extract increased the thickness, improved the mechanical properties and reduced the moisture content, water vapor permeability, transparency, and solubility. Also, nanocomposite films containing titanium dioxide nanoparticles and saffron extract showed antioxidant properties (% 80%) and acceptable antimicrobial effects, especially against gram-positive Staphylococcus aureus bacteria. According to the results of this study, this type of packaging can be suggested as a suitable alternative to synthetic packaging.

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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.

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Green synthesis plays an important role because of 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 Ag/AgCl /TiO₂ three-component nanocomposite using Zataria Multiflora plant and evaluate the size and morphology of the produced nanoparticles. For this purpose, synthesis, and characterization of Ag/AgCl/TiO2, a three-component nanocomposite was done using Zataria Multiflora plant extract using UV-Vis, XRD, TEM, and FTIR techniques. Then, the characteristics of nanocomposites were investigated. The results showed that the largest diameter of the non-growth halo was observed in all studied bacteria in the nanocomposite containing 50% color 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. Overall, the obtained results showed that Zataria Multiflora plant extract, along with silver and titanium dioxide nanocomposites, has a high potential in producing nanoparticles with high purity, in nanometer sizes, with antimicrobial properties, which has properties in the food industry as a coating and film.

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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.