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Research subject: One of the major problems we face with the growth of various industries around the world is the environmental pollution of heavy metals. One of the most toxic heavy metals that is problematic even at low concentrations is Cr (IV).
Research approach: In this study, the removal of this toxic heavy metal was investigated with high efficiency by UIO-66-MnFe2O4-TiO2 magnetic adsorbent. For this purpose, magnetic nanocomposite (UIO-66-MnFe2O4-TiO2) was synthesized based on metal-organic framework (MOF) for adsorption of Cr (IV). The choice of the hydrothermal method for the synthesis of UIO-66 in addition to its simplicity resulted in the production of pure and efficient UIO-66, which produced very high efficiency during the experiments. MnFe₂O₄ nanoparticles were used to magnetize the adsorbent. To increase the magnetic properties and increase the loading efficiency of the MnFe₂O₄ nanoparticles, TiO₂ nanoparticles were used to increase the loading rate on the adsorbent. XRD, SEM, FT-IR, BET, VSM and EDX tests were used to the characterization of the adsorbent properties.
Main results: Effect of four effective variables during adsorption experiments such as adsorbent content (0.05 to 0.25 g), pH (2 to 6), adsorption time (15 to 75 min), initial metal ion concentration (200 to 1000 mg / l) at five levels (+2 to +2) were investigated using experimental design with response surface methodology (RSM) and central composite design (CCD). The best conditions were determined for the independent variables for the initial metal concentration of 552 mg /l. The optimum pH was obtained 4 during the experiment. Finally, the optimum values were achieved for adsorption parameters such as adsorption time and adsorbent amount were 42.3 min and 0.143 gr, respectively, and also the maximum adsorption rate was obtained 98%. Investigation of the adsorption isotherm kinetics showed that the pseudo-second-order model and Langmuir isotherm fit the Cr (IV) data well. After the adsorption process, the adsorbent can be removed from the environment by a magnetic field.

 

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Research subject: Nanomaterials are substances that, because of their size, can easily penetrate small pores and apply their impact. Nanofluids can allow appropriate wettability change in the reservoir rock, therefore, an accurate understanding of the behavioral mechanisms of these nanofluids is important in changing the wettability. This is because if there is no proper understanding of these mechanisms, they may exhibit the opposite behavior and cause damage to the reservoir. In previous research, CuO / TiO2 / PAM nanocomposite was synthesized and mechanistically introduced.
Research approach: In this study, in continuation of the previous study, the behavioral and mechanism study has been investigated in a more accurate and documented manner, and spectral absorption tests, chemical flooding, and relative permeability diagrams confirm the effectiveness of enhanced oil recovery results of this nanocomposite. In carbonate rocks due to the positive surface charge of the rock and the negative charge of the nanocomposite, adsorption of nanomaterials in a double electrode layer state has been suggested as the dominant mechanism of wettability change. In sandstone rocks due to the charge coincidence of rock surface and nanomaterials which are both negative, the mechanism of disjoining pressure was the dominant mechanism of wettability change. To prove the abovementioned behaviors 200 ppm concentration of nanofluid was analyzed by spectroscopy method of adsorption analysis to validate the attraction forces of the nanocomposite with carbonate rocks and repulsion forces with sandstones.
Main results: Dynamic chemical flood tests were performed to confirm the effectiveness of this material in increasing oil production and showed 8.5% and 6.35% increase in oil production for carbonate and sandstone lithologies, respectively. Relative permeability diagrams showed an intersection point in the carbonate system with a 10% increase in water saturation and an intersection point in the sandstone system with a 12% increase in water saturation and the behavioral effect of the material at the studied concentrations.

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Introduction: Nanotecnology could solve most of problem of biomedical and cause improve in health and pharmacology field. Also this industrial cause to eliminate food pathogenic bacteria.increase of food pathogenic bacteria and resistance them to different antibiotics caused usage of nanotechnology by researchr and pharmacologiests. Material and Methods:In this reseach is studied antimicrobial effect of nanoparticles of silver,TiO2 against on food pathogenic bacteria such as Staphylococcus aureus PTCC 1431 and Listeria monocytogenes by determination MIC and MBC. Result: Silver nanoparticle was synthezied with 103 nm of size and consentraion of 1 mili molar,nano TiO2 with 21 nm of size and consentrain of 1% have antimicrobial effect against on Staphylococcus aureus PTCC 1431 Listeria monocytogenes . Conclusion: Since that antimicrobial activity of silver ,TiO2 nanoprticles against on food pathogenic bacteria (Staphylococcus aureus PTCC 1431 and Listeria monocytogenes) is proved, is suggested to packaging antimicrobial food. Keywords: Silver nanoparticle,TiO2,,Antimicrobial effect, Staphylococcus aureus PTCC 1431 Listeria monocytogenes

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Astaxanthin is a precious material and has many favorites for human; it is extracted from some creatures such as Haematococcus lacustris. Researchers try to maximize the production of this material. In this research effects of linoleic acid (LA), TiO2 and SiO2 Nanoparticles (NPs) were investigated on astaxanthin production, and expression of two astaxanthin metabolic pathway genes (CRTO and CRTR). The microalgae was cultured in BBM medium for 19 days autographically. In 3rd day, treatments were added to the cultures and astaxanthin measured in 3 days respectively in logarithmic and stationary phases, also RNA was extracted, Real-time PCR applied and Gene expression investigated in 11th. 30 µM LA and TiO2 NPs (40 mg L-1) induced 3.4 and 1.5 times astaxanthin production compared to the control, furthermore, CRTO and CRTR under 30 µM LA and SiO2 NPs (40 mg L-1) treatments displayed the highest gene expression. It was demonstrated that special concentration of Linoleic acid and TiO2 NPs, as inducers, could be used for astaxanthin production; also, Linoleic acid has a direct relationship with astaxanthin production and CRTO´s gene expression in the microalgae.

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Cellular energy allocation (CEA) test was performed in order to investigate the effects and costs of bare carbon nanotubes (CNTs) and CNTs in combination with titanium dioxide nanoparticles (CNTs/TiO₂-NPs) on Glyphodes pyloalis Walker after 24, 48 and 72 hours of exposure to 100, 200, 300, 400 and 500 ppm of the treatments. Results showed the negative correlation between total lipid amounts and concentrations of treatments (i.e. CNTs and CNTs/TiO₂-NPs) as well as exposure time. Contrary to CNTs treatments, carbohydrate contents were affected by both of CNTs/TiO₂-NPs concentration and time of exposure. Results showed that the effect of bare CNTs in the enhancement of glycogen content appeared significantly faster than that of CNTs/TiO₂-NPs. Increasing time of exposure to all concentrations of CNTs, except for 100 ppm, prevented enhancement of protein content. The effect of bare CNTs on the reduction of protein contents was faster and greater than that of CNTs/TiO₂-NPs. The results indicated that G. pyloalis cannot regulate internal CNTs and CNTs/TiO₂-NPs concentrations efficiently without considerable impact on the energy reserves (Ea). The comparison of energy consumed (Ec) in treated larvae showed that CNTs/TiO₂-NPs reflected the higher energy demand of the stress response than CNTs. Generally, CEA was significantly decreased as the concentration of CNTs treatments increased. More reduction in CEA amount of all treatments by CNTs/TiO₂-NPs than that of the control is also probably considered as a cost to deal with detoxification when the concentration increased and at all the tested time points. Therefore, CEA test might be considered as an early biochemical biomarker for assessing immediate response of organisms after acute exposure to stressors and thus could be applied to risk assessment of nanomaterials.

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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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UV-TiO2 Photocatalytic Degradation of Compost Leachate Abstract The growing rate in solid wastes production leads to considerable generation of leachate. Leachate is defined as the aqueous effluent generated as a consequence of precipitation percolation through wastes, biochemical processes in wastes body and the inherent water content of wastes themselves. Since the leachate contains significant amount of organic and inorganic compounds, it is not allowed to be directly discharge to the environment. Conventional treatment techniques to remove organic matters from leachate include physical, chemical and biological processes. Most of these techniques are non-destructive and do not solve the environmental problems because the wastes are simply transferred from water to another phase creating secondary wastes pollution. Biological method was regarded as the most efficient and cheapest process to eliminate organic materials from leachate. However, biological process cannot usually remove refractory substances. Therefore, the effluent values of the organic content do not meet the standards of the treated wastewater with respect to persistent contaminants. Due to limited biodegradability, the treatment of leachate, apart from biological methods necessitates the application of other methods, which complement and support the main process. Advanced oxidation process has been intensively studied in the past decade to improve the removal of these large refractory organic molecules or to transform them into more easily biodegradable substances. Among them photocatalytic process is one of the appropriate methods for final treatment of these kinds of waste. In this study, application of photocatalytic process via UV light and TiO2 Nano particles immobilized on concrete surface in post-treatment of composting leachate was investigated. This investigation was conducted in laboratory scale and batch mode. A biological pre-treated leachates sample which contains some macromolecular organic substances that were resistant to biological degradation were collected from the effluent of leachate treatment facility, of Gorgan composting plant (Golestan, Iran). UV-C lamps with different power in the range of 8-107 W at a constant distance of 10 cm from the surface of the leachate were used as the source of irradiation. Pervious concrete was constructed using LECA lightweight aggregates with the dimension of 30*10*10 cm. Immobilization of TiO2 on concrete surface was done by using concrete sealer. In order to investigate the effect of each parameter individually, some experiments were carried out. The results showed that the presence of nanoparticles and UV radiation alone did not significantly affect on the COD removal. According to the conducted experiments the maximum COD removal of 62% was achieved after 20 hr radiation with 7.5 mW.Cm-2 intensity in pH value of 5 and in presence of 60 g.m-2 of TiO2 coated on concrete. According to Iranian environmental standards and with regard to organic loading of leachate, removal efficiency of this process was in such a way that it could be directly discharged into the environment. Keyword: Leachate treatment, Photo Catalysis reaction, TiO2, light intensity, Color, COD

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One of the quality characteristics of welded joints in gas metal arc welding (GMAW) is weld height (WH). This paper highlights an experimental study carried out to develop a model using artificial neural network (ANN), to predict WH in GMAW in the presence of TiO2 nano-particles. For developing the model, the arc voltage, welding current, welding speed, percentage of Ar in Ar-CO2 mixture and thickness of TiO2 nano-particles were considered as input parameters and WBH as the response. A Doehlert design matrix was employed in the experiments to generate experimental data. The ANN model was developed and validated by conducting five extra runs. The remarkable outcome of this study is the mechanism of arc constriction due to interacting effects between welding input parameters and TiO2 nano-particles. Moreover, the results showed that increasing thickness of TiO2 nano-particles up to almost 0.9 mm increased weld height whereas, its further increase up to 1.0 mm, decreased weld height subsequently. In fact, this variation in weld height could be due to thermal dissociation of TiO2 nano-particles and CO2 releasing oxygen onto weld pool surface, which influenced its surface tension and consequently, changed direction of the Marangoni convection of fluid flow in weld pool and as a result, affected WH. For ANN technique, MSEtrain=0.0066, MSEvalidation=0.0063 and MSEtest=0.0093. Finally, it is to be concluded that ANN is an accurate technique for predicting weld height.

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The most important post harvesting factors that limiting grape berries after post harvesting are water losing and fungal decay. In this study, effect of titanium dioxide (TiO₂) and soy protein isolate edible coating against postharvest decay and increasing the storage life of table grape cultivar was investigated. Uniform clusters with no disease and physical damage were packed with coated and uncoated (control) TiO₂ nanoparticles. Then clusters were maintained for 31 days in cold storage at 0 ± 1 °C and RH 90 ± 5%. Grape berries abscission rate, total soluble solids (TSS), titratable acidity (TA), total phenolic content, color and clarity of grape berries, pH, antioxidant activity and total sugar characteristics were measured at intervals 6 days. The statistical analysis of results showed that the TiO₂ nanoparticles treatment had significant effects in cluster and grape berries weight losing, fungal infection, TA, total phenol content and coefficient of ripening. This treatment had best flavor, quality, appearance and marketability compared with the samples without TiO₂ nanoparticles treatment. In addition, the samples that treated with TiO₂ nanoparticles showed higher TSS, TA, antioxidant activity, total sugar and total phenolic content. In the present study, two varieties of grapes treated with TiO₂ nanoparticles in the comparison of control samples had higher quality at the end of the storage period.

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Since woven fabrics have uniqe characteristrics such as light weight, flexibility, high strength, etc. and they are also capable to be improved for mechanical properties by nano thechnology, it is expectal to gain more efficient composite using intrinsic properties of the ceramic nanoparticles and proper coating method. The uniqe properties of the nanoparticles such as high elastic modulus, high strength to weight ratio etc. as well as participating in defeat mechanisms agains external loadings, can be of the factors reinforcing the textiles. Al2O3-13%TiO2 coatings were deposited on Kevlar Fabric substrates from nanostructured powders using atmospheric plasma spraying (APS). A complete characterization of the feedstock confirmed its nanostructured nature. Coating microstructures and phase compositions were characterized using SEM, and XRD techniques. The microstructure comprised two clearly differentiated regions. One region, completely fused, consisted mainly of nanometer-sized grains of α-Al2O3 with dissolved Ti+4. The other region, partly fused, retained the microstructure of the starting powder and was principally made up of nanometer -sized grains of γ-Al2O3, as confirmed by FESEM. coatings were in average slightly lower than the values for nanostructured coating. The results of tensile testing on kevlar fabrics before and after coating showed that APS could improve tensile strength up to 60%. High velocity impact test (V50) performed on coated fabrics well indicated that their ballistic limit experienced a significant increase. In addition, the results of V50 showed revealed that APS can decrease final weight of new composite panel compared to plain polyetylen panel with identical protection level.

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In this study, a baffled photocatalytic reactor was used to treat wastewater containing azo dye. The baffles made of Plexiglas covered by TiO2 nanomaterials placed vertical in the reactor, were used. Using this reactor could enhance in the wastewater passage time, decrease in contact distance due to existence of the colored wastewater and the effect of preventing the passage of UV ray, bring about turbulence in the current, prevent from short circuit phenomenon, increase at the current length, and cause enhancement in effective surface against the relatively low occupancy level that make it possible to construct this kind of reactors in larger scales. The dimensions of the Reactor were 20 cm*25 cm*50 cm and the baffle dimensions used in the reactor were selected 20 cm*12 cm. The photocatalyst particles were fixed on baffles and then the experiments were conducted based on the experimental design by Design Expert software. In order to ensure adequate waste water to pass from the photoreactor, the rotary flow regime was used in the original design. In the research, Methyl orange one of the anionic dyes with the chemical formula C14H14N3NaO3S was used. This azo dye was the kind of amino benzene and has a functional azoic group (-N = N-) and cofactors NaSO3 and now widely used in dyeing textile, wood, paper, leather and printing applications. In order to investigate the effect of the main factors and optimizing colored wastewater treatment process by using TiO2 nanoparticles in the baffled reactor Response Surface Methodology, central composite design (CCD), was used. Based on the results, reducing the pH and initial dye concentration had synergetic effect on color and COD removal simultaneously. The effect of pH less than 5 and less than 75 mg/L concentrations are more rapidly. This phenomenon was a result of amphoteric behavior of TiO2 and the weakening of oxidation ability of the produced holes in alkaline conditions. The pH of the solution influence on how the TiO2 surface is ionized and leads to amphoteric behavior the TiO2 nanoparticles under different conditions and this behavior changes the oxidation ability of the process. Another reason for this phenomenon could be described as the reduction in light penetration due to increased dye concentration in the solution and the more dye adsorption on the surface of TiO2 causes a part of UV energy is absorbed by the molecules of the dye. Although Methyl orange is an anionic dye with the negatively charged sulfonic group thus in high pH, hydroxyl radicals lose the chances of reaction with the trapped dye quickly. At the same time reducing the pH and increasing the reaction time also increases the efficiency of COD and color removal and enhanced for the pH below 4 and after 6.5 hours for dye removal and at pH below 5 and after 8 hours for COD removal. This was due to increased opportunities for photocatalytic activity in acidic pHs reduce the initial dye concentration and increase the reaction time had amplified effect in efficiency of decolorization and reduction of COD. The rate of the phenomena was more obvious for the dye concentration less than 50 mg/L and after 8.5 hours. The results showed that the color removal efficiency was more than COD removal efficiency. The most noticeable reason for this phenomenon is the breaking of the colored azoic bond and producing colorless intermediate products that decrease removal efficiency during tests. The maximum amount of COD and color removal when the 50 mg /L initial dye concentration and at the pH= 5 were 98.81 and 69.7 percent, respectively, after 9.5 hours. The results data comply with reduced quadratic model with a correlation coefficient (R2) 94.95 and 95.30 percent for color and COD removal respectively that validate the model results. Laboratory assessment also indicated that due to the very small difference between the results of the represented model and the experimental data, the model was consistent with acceptable confidence level.

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The objective of this study was to investigate the synergistic effect of nano titanium dioxide (TiO2-N) and Mentha piperita essential oil (MEO) on the equilibrum moisture sorption isotherm and microbial growth rate of Staphylococcus aureus of cassava starch film. For this purpose, cassava starch biocomposite film with the addition of 1, 3 and 5% TiO2-N and 1, 2 and 3% MEO, and glycerol as a plasticizer were obtained by the casting method. The equilibrium moisture absorption isotherm and antibacterial activity of prepared nanobiocomposite films against Staphylococcus aureus were examined. The obtained results demonstrated that by addition of nanoparticles and essential oil to the starch biocomposites, the equilibrium moisture absorption isotherm curve was shifted to lower moisture content. The microbial tests stated that the pure cassava starch film (control) showed no antibacterial activity against the Staphylococcus aureus and the antibacterial activity significantly increased with increasing concentration of both TiO2-N and MEO in the starch films (p<0.05). However, the antibacterial activity of TiO2-N nanoparticles was higher than MEO. Addition of TiO2-N and MEO increased lag phase and decreased log phase in microbial growth curve. Finally, according to the obtained results in this study, it can be concluded that incorporation of TiO2-N and MEO combination improved the antibacterial activity of cassava starch biocomposites against Staphylococcus aureus and these bionanocomposite films can be used for packaging and extending the shelf life of food products.

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Portland cement is a crucial mineral chemical that is globally produced in large quantities. It has been reported that in 2011, approximately 3.6 billion tons of Portland cement were produced, and its demand continues to grow. However, this industry's expansion has resulted in increased environmental risks. Therefore, it is important to conduct research to enhance the sustainability of this product. The utilization of nanomaterials in cement and concrete materials has received significant attention in recent years. Employing nanotechnology to modify cement-based materials can significantly enhance the efficacy of this inorganic binder. Primarily, nanoparticles possess the capability to fill the porosity within the cement structure and exhibit pozzolanic properties that reinforce concrete. Additionally, the high specific surface area of nanomaterials facilitates increased reactivity at the nanoscale, thereby enhancing cement hydration and subsequently improving its mechanical properties.

Despite cement and concrete being known for their strength, they are also inherently brittle, which hinders their mechanical performance. In recent years, various nanomaterials have been utilized to address this weakness due to their high specific surface area and strengthening capability in different matrices, including cement. This study aims to evaluate the impact of incorporating a binary nanocomposite of titanium dioxide nanoparticles and graphene oxide to enhance the mechanical properties of the Portland cement. 

For hybridization, electrostatic adsorption mechanism was used to connect TiO2 nanoparticles on graphene sheets and synthesize TiO2–GO nanocomposite. In this work, TiO2 powder was processed in nitric acid to accumulate protons in the form of H+ functional group on the surface of nanoparticles and make it positively charged. On the other hand, chemically produced GO suspension has an intrinsic negative charge due to the formation and presence of hydroxyl groups (OH–) on its surface. Therefore, the combination of these two charged substances with the opposite charge under several hours of stirring causes them to be connected and attracted to each other through electrostatics.

Cement paste with a water-to-cement ratio of 0.38 was prepared and hydrated for different durations (7, 14, and 28 days). Nanostructured reinforcement with a fixed concentration of 0.05 wt.% GO and varying concentrations of 0.5, 1, and 1.5 wt.% TiO₂ were added to the cement. The resulting cement paste samples were analyzed for compressive strength, porosity, and microstructure. The study revealed that the sample containing 1 wt.% TiO₂–0.05 wt.% GO exhibited the best mechanical behavior, with a 55% higher compressive strength compared to the unreinforced cement sample. Furthermore, this sample had the lowest porosity. Microstructural analyses indicated that the reinforced sample had a reduced porosity, improved hydration acceleration, and enhanced overall integrity of the structure, leading to the significant improvements in its mechanical properties.