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Nowadays, application of enhanced oil recovery methods has increased; therefore it’s necessary to determine their impacts on environment and human life. So, this research investigates the environmental impacts of conventional enhanced oil recovery methods and new methods such as using electromagnetic waves, ultrasound waves, and nanoparticles. The investigations show that electromagnetic waves and ultrasound can effectively remove many environmental pollutants. Characteristics of the wave and the type of formation determine that these waves have different effects on the formation, and efforts should be made to understand these effects to prevent damage to the formation. Nanoparticles can also reduce the quantity of pollutants in the environment. According to the mechanisms of entrapment of nanoparticles in the porous medium, they may remain in the reservoir and find their way to the underground water over time, so their environmental effects should be considered in the long term. A better knowledge of new methods of increasing oil extraction will lead to the identification and use of more suitable methods with less environmental effects (compared to conventional methods).

 

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Dispersion type of layered clay plated in aqueous media creates different structures and affects the final properties of its suspension. On the other hand, the presence of different electrolytes in some industrial applications affects the stability of clay suspensions. Considering the application of clay nanoparticles in various industries and the importance of this subject, in this research, the effect of preparation method, nanoparticle concentration, type and ionic strength of electrolytic medium and time elapsed on the stability behavior of laponite nanoparticles suspensions were studied. The results showed that preparing of the suspensions indirectly, results in more stable samples. It was observed that with increasing of sodium chloride concentration, the repulsion between the clay plates decreased and the phase separation and instability of the suspensions increased at higher NaCl concentrations. Furthermore, it was seen that in all electrolyte media, gel-like structure develop with increasing of nanoparticle concentration. In presence of bi-valance CaCl2 salt, most of suspensions were unstable and have two phases and increasing of this salt concentration had not significant effect on their stability. In electrolyte media containing mono- and bi- valance salts (studied in this research), concentration of calcium cation determines the type of stability behavior of laponite nanoparticles suspensions.

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In general, temporary well plugging is essential for repairing of oil and gas wells due to their long life time. One of the newest methods used for this purpose is gel polymer plugging. The strength of the gel in the well conditions is one of the most important challenges in the application of gel polymer in the temporary well plugging in work over operation. In this study, silica nanoparticles were used to improve the strength of polymer hydrogels. The bottle and rheological tests were used to determine the gel strength in desired well conditions (high temperature and high salinity). Also, the gel strength properties and swelling behavior were studied in various conditions such as distilled water, formation water, tap water and oil. It was observed that the strength of the gel increased from 520Pa to about 36kPa (5000% increase) by adding nanoparticles. Also, the gel swelling in the aqueous solution has been significantly reduced. Based on the results obtained in this study, a polymer gel containing 9 wt.% of silica nanoparticles with structural strength and thermal stability at 90 °C was introduced for field studies.

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In the Magnetically Assisted Chemical Separation (MACS) process, tiny ferromagnetic particles coated with solvent extractant are used to selectively separate radionuclides and hazardous metals from aqueous waste streams. The contaminant-loaded particles are then recovered from the waste solutions using a magnetic field. In the present study, Cyanex272 or C272 (bis (2,4,4-trimethylpentyl) phosphinic acid) coated magnetic particles are being evaluated for the possible application in the extraction of Uranium (VI) from nuclear waste streams. The uptake behaviour of U(VI) from nitric acid solutions was investigated by batch studies.
Adsorption of uranium (VI) from aqueous solution onto adsorbent was investigated in a batch system. Adsorption isotherm and adsorption kinetic studies of uranium (VI) onto nanoparticles coated Cyanex272 were carried out in a batch system. The factors influencing uranium (VI) adsorption were investigated and described in detail, as a function of the parameters such as initial pH value, contact time, adsorbent mass, and initial uranium (VI) concentration. Magnetically Assisted Chemical Separation (MACS) process adsorbent showed best results for the fast adsorption of U (VI) from aqueous solution at aqueous phase acidity value of 0.5 molar. In addition, more than 80% of U (VI) was removed within the first 2 hours, and the time required to achieve the adsorption equilibrium was only 140 minutes. Langmuir and Frendlich adsorption models were used for the mathematical description of the adsorption equilibrium. Equilibrium data agreed very well with the Langmuir model, with a maximum adsorption capacity of 48 mg.g^-1. Adsorption kinetics data were tested using pseudo-first-order, pseudo-second-order and intra-particle diffusion models. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step.
 

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In order to understand the importance of particle size and agglomeration for nano-eco-toxicological studies in aquatic environments, the acute toxicity of two different types (suspended powder and colloidal) of silver nanoparticles (AgNPs) were studied in alevin and juvenilerainbow trout. Fish were exposed to each type of AgNPs at nominal concentrations of 0.032, 0.1, 0.32, 1, 3.2, 10, 32, and 100 mg/L. Lethal concentrations (LC) were calculated using a Probit analysis. Some physical and chemical characteristics of silver nanoparticles were determined. In the case of colloidal form, particles were well dispersed in the water column and retained their size; but in the case of suspended powder, particles were agglomerated to large clumps and precipitated on the bottom. In alevins, the calculated 96 h LC50 values were 0.25 and 28.25mg/L for colloidal and suspended powder AgNPs respectively. In the case of juveniles, the 96h LC50 of colloidal form was 2.16mg/L, but suspended powder did not caused mortality in fish even after 21 days. The results showed that both in alevin and juvenile stages, colloidal form is much toxic than suspended powder; this shows increase of nanoparticles size due to agglomeration, will reduce the toxicity. Silver nanoparticles are toxic materials and their release into the water environment should be avoided.

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Aim: Most scientists are trying to treat cancer, and in this regard were produced numerous anticancer drugs, that adverse effects on non-target tissue. To overcome this, drugs freight to magnetic nanoparticles Chitosan and its carboxymethyl secondary coumpands are biopolymers that are non-toxic, biodegradable therefore found applications in biomedical field. We explain here that glycerol monooleate covered magnetic nanoparticles (GMO-MNPs) capable of transporting hydrophobic anticancer drugs. Method: In the present study, we have expanded 5-fluorouracil (5-FU) that loaded on chitosan MNPs for targeted cancer therapy. Results: The modified nano-adsorbent was then characterized by Fourier Infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), elemental analysis of CHN (9) and thermal weighing analysis (TGA). Lab conditions such as pH, contact time were optimized. To analyze the structure of the sample, X-ray diffraction spectroscopy was used to investigate the magnetic properties of the nanosized particles synthesized by the magnetometer and to detect the phase type formed on the monolayer glycerol matrix network using a polarizing light microscope. Also, the study showed essential oil release in the external environment of 90% for 30 hours. Conclusion: The optimized magnetic nanoparticles according to SEM image, exhibited segregated nanoparticles with sub-spherical smooth morphology and also the high thermal stability of 5-Fluorouracil nanoparticles which indicated a well-established structure of nanoparticles.

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In this research, general performance of Radial basis function (RBF) Artificial neural networks in experimental data on effect of the NiO, WO3, TiO2,ZnO and Fe2O3 nanoparticles in different temperatures and mass fractions on the viscosity of crude oil has been studied. The morphology and stability of the nanoparticles has been analyzed by DLS and TEM analysis, the results showed that the average diameter of the nanoparticles is from 10 to 30 nm which defers for different oxide nanoparticles. The general method for calculating the optimum span of the Isotropic Gaussian function with special algorithm for learning RBF networks, has been presented. This study's results declared that the RBF artificial neural networks, because of having strong academic basis and having the ability to filter the noises, has a good performance. With increase in temperature, the ratio of the viscosity of the nanofluids decreases compering to the viscosity of the basefluid. Also with increase in nanoparticles mass fraction the related viscosity increases boldly. For temperatures higher than 50°C, the related viscosity is less than the viscosity of the basefluid.

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In recent years, with the advancement of nanoscience, many scientists have used nano materials to solve existing problems in various sectors of oil industry. Nanofluids made with these materials can facilitate the separation of oil and gas in a reservoir and increase oil recovery factor compared to current methods. Therefore, in this work, the effect of clay nanoparticles on oil recovery factor was investigated. For this purpose, two different base fluids, water and ethanol, were used to disperse the nanoparticles. The effect of adding clay nanoparticles on viscosity changes and interfacial surface tension was determined. Also, in order to investigate the effect of nanoparticle concentration in the base fluid on the ultimate oil recovery factor, nanofluids with 3 and 5 wt% were prepared. Results show that oil recovery factor increases significantly in these conditions by adding them into the base fluid, though nanofluids included clay nanoparticles have less stability. Also, the effect of these nanoparticles dispersed in water is greater than in ethanol. For example, at 5 wt%, oil recovery factor for water based nanofluid was 49.7% and for ethanol based nanofluid was 46%.

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Background: This study was performed to determine antifungal activity of silver nanoparticles (nano-Ag) compared to voriconazole on clinical and standard strains of Aspergillus fumigatus.
Materials and Methods: Inhibitory potency of nano-Ag was determined using microtiter broth dilution method. Susceptibility tests were performed against A. fumigatus isolated from BAL (bronchoalveolar lavage) of patients who suffered from respiratory problems and compared with the strain (ATCC: 204305) by broth dilution antifungal susceptibility test of filamentous fungi approved by the Clinical and Laboratory Standards Institute M38-A. In addition, cytotoxicity effect of silver nanoparticles was studied on epithelial cell line by MTT assay.
Results: From 60 BAL samples the following strains were isolated; A. flavus (n=21), A. niger (n=3), and A. fumigatus (n=1). The minimum inhibitory concentration (MIC₉₀) values of nano-Ag were 0.25 and 0.5 μg.mL^-1 for standard strain and clinical isolates respectively. The  Minimum Fungicidal Concentration (MFC) values of nano-Ag were 0.5 and 1 μg.mL^-1for standard strain and clinical isolates respectively. MIC90 values of voriconazole were 0.125 and 0.25 μg.mL^-1 for standard strain and clinical isolate respectively. The MFC values of voriconazole were 0.25 and 0 μg.mL^-1 for standard strain and clinical isolates respectively. Silver nanoparticles exhibited low cytotoxicity in 0.25 μg.mL^-1 concentration.
Conclusion: Our results showed high antifungal activity of silver nanoparticles against Aspergillus isolates. Furthermore, the availability of a wide form of nano-Ag structures can be considered as novel agents to decrease fungal burden in medical application.

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Gold nanoparticles have received considerable attention in recent years because of their promising applications in diagnostic imaging, biosensors, biolabels, and drug and gene delivery systems. The chemical methods of nanoparticle synthesis are the most widely and traditionally used methods. Production of nanoparticles by chemical methods causes contamination from precursor chemicals due to the use of toxic solvents and generation of hazardous by-products. On the other hand, the physical methods have low yield and high cost. Hence, there is an increasing need to develop low cost, non-toxic, biocompatible and environmentally benign processes for synthesis of metallic nanoparticles where the biological approaches for synthesis of nanoparticles gain importance. In this study, we investigated the biosynthesis of gold nanoparticles using Streptomyces sp. ERI-3. Streptomycessp.ERI-3 was isolated from the soil of Ahar Copper Mine (Ahar, Iran) and its biomass was incubated at 28ºC on a rotary shaker (200 rpm) for 48 h. The nanoparticles were characterized by means of UV-vis spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM).The nanoparticles exhibited maximum absorbance at 540 nm (special wavelength of gold nanoparticles) in UV-vis spectroscopy. The XRD spectrum of gold nanoparticles exhibited 2Ө values corresponding to the gold nanocrystals. The TEM micrographs revealed the extracellular and attached to cell surface formation of gold nanoparticles in the size range of 50-100 nm with spherical morphology.  

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Research Subject: Removal of industrial wastewater especially from textile and dyeing factories is always important actions to control of pollutions. Using of polymeric adsorbents is an important method for removal of dyes from industrial wastewater. In this research work, designing and fabrication of PVA-based adsorbent with proper potential for removal of green malachite from industrial wastewater has been reported.
Research Approach: For fabrication of adsorbent 4 wt.% PVA was gelled in the present of 10 wt.% glutaraldehyde as cross-linker and punched. The punched hydrogels were porous with freeze drying method. For improving the adsorption ability, graphene and TiO₂ were used. The adsorption of green malachite with prepare adsorbent was measured timely to determine the optimum percentage of nanoparticles. In addition, the effect of contact time and the presence of UV on the adsorption of pollution was investigated. Finally, the adsorption isotherms and thermodynamics study were investigated in different time.
Main Results: The results of adsorption of pollution with PVA/graphene adsorbent in different times showed that 0.5 wt.% is the optimum loading of graphene in the PVA matrix. This value was 3 wt.% for TiO₂. The adsorption percentage via optimum adsorbent in dark condition showed that one minute after addition of adsorbent the adsorption percent increased to 75% indicating the high capability of the adsorbent in adsorption of tested pollution. The porous structure was confirmed via SEM image. By comparing the correlation coefficient for Langmuir and Freundlich isotherms it was found that Freundlich isotherm has better agreement with the findings of the current study. In other words, adsorption of green malachite with fabricated adsorbent was done multi layered. The thermodynamics studies showed that due to negative value of Gibbs energy the adsorption reaction of green malachite with fabricated absorbent is automatically.

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In biological methods, microorganisms such as bacteria, fungi, actinomycets and yeasts are used to produce metal nanoparticles. Fungi are extremely good candidates in the synthesis of silver nanoparticles because of their ability to secrete large amounts of enzymes. The aim of this study was the biosynthesis of silver nanoparticles by Penicillium spp. isolated from the soil of plump and zinc mine in Zanjan city (Iran). After culturing, growth of colonies and isolation of Penicillium spp., 15 g of the fungal biomass was mixed into 1 mM silver solution for 72 h incubation. The production of silver nanoparticles was characterized by UV-vis spectroscopy, X-ray diffraction(XRD) and transmission electron microscopy. Among the sixteen kinds of isolated fungi, six species were recognized as Penicillium of which just the fungus Penicilliumbrevicompactum was found to be able to produce silver nanoparticles. The production of silver nanoparticles was preliminarily approved by observing  the color change of the reaction solution from colorless to yellowish brown. The synthesis of silver nanoparticles was confirmed by observing the characteristic peak at 406-425 nm. The presence of crystalline silver nanoparticles was confirmed by observing peaks in (111), (200), (220), (311) in the XRD  analysis. Transmission electron microscopy images showed that silver nanoparticles were produced in the size range of 50 -100 nm in spherical shape mainly extracellular at the surface of mycelium. The fungus was recognized to be Penicilliumbrevicompactumusing slide culture method, growth on Czapek yeast agar and Keratin-sucrose agar.

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Research Subject: Poor mechanical strengths and lack of thermal stabilities of hydrogels confine their extensive practical applications in many areas. The growing scientific need for solving this problem and achievement to the hydrogels with improved properties has led to the design and production of the nanocomposite hydrogels.
Research Approach: The polymeric networks of nanocomposite hydrogels compared to the ordinary hydrogels have improved elasticity and rheological properties. Other points that increase the importance of structural studies of nanocomposite hydrogels are the high strength of these materials versus the application of external forces, as well as maintaining its structure against increasing of temperatures. In this regard, the type and amounts of nanomaterial, the preparation method and formation of hydrogel network have a significant role in improving the physical, chemical and biological properties of hydrogels, and, it must be noted that these parameters will depend on the application of nanocomposite hydrogels. This also highlights the need for the production of nanocomposite tailored hydrogels. Therefore, orientation of the range of nanomaterials, the preparation method and product identification, along with sufficient information on the application of these materials, might have an important role in ensuring the success of these materials, requiring comprehensive library research and studies on polymerization processes, morphology and rheology.
Main Results: In this review article, the scientific advances in the field of nanocomposite hydrogels, focusing on its types based on the type of nanoparticles, its properties, preparation methods, identification methods with a new perspective on rheology, thermal analysis and morphology is investigated. Finally, the applicability of these materials is collected in a comprehensive table in various fields such as tissue engineering, enhanced oil recovery, agriculture, and etc…

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Research subject: Due to the public's attention on the environmental issues as well as strict environmental regulations, the eco-friendly methods for nanoparticles have received considerable attention in the recent years.
Research approach: In the present study, a mixed oxide nanoparticles containing cerium and zirconium (Ce_x-Zr_1-xO₂) was fabricated the in supercritical water (SCW) medium. The synthesized nanoparticles were characterized by various analyses, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
Main results: The results of the analyses demonstrated that fine nanoparticles with mean size of 13±3 nm, with high crystallinity, and with appropriate size distribution and surface area were synthesized by SCW. Moreover, an oxygen storage capacity (OSC) as high as 1.25 mmol O₂/g was estimated for Ce_x-Zr_1-xO₂ nanoparticles through temperature programmed reduction in hydrogen (H₂-TPR). According to the obtained results, the Ce_x-Zr_1-xO₂ nanoparticles could be a suitable candidate for catalysts of oxidation processes as well as three-way catalyst for control of automotive exhaust gases.

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Abstract
Research subject: Nanocomposites are a new class of materials that have at least one of their major constituents, at least in one dimension, in the range of one to one hundred nanometers. Typically, nanocomposites have different and superior properties in terms of mechanical and physical properties than conventional composites.
Research approach: In this study, polyvinyl acetate was prepared by emulsion polymerization for polymer matrix. Then the diamond nanoparticles were modified with silane agent. Finally, polyvinyl acetate / diamond nanocomposite was prepared and analyzed with 0.5, 1, 1.5 and 2 wt% of modified diamond nanoparticles. To determine the properties and structure of the nanocomposite, FTIR, TGA, RMS, FESEM, oxygen permeation analysis was used in the films produced and contact angle measurements.
Main results: FTIR Analysis revealed that the modification of the diamond nanoparticles with the silane agent was well performed. FESEM images show that homogeneous nanocomposites were created. Oxygen permeability in polyvinyl acetate / diamond nanocomposite film decreases with increasing percentage of modified nanoparticles in nanocomposite. This is a valuable property if this nanocomposite is used as a fruit preservative coating. Contact angle measurement of polyvinyl acetate / diamond nanocomposite showed that by increasing the amount of modified diamond nanoparticles from 0.5 to 2 wt %, the hydrophobicity of nanocomposite film increased. Therefore, by increasing the specific amount of nanoparticles to the polymer matrix, the polymer properties such as heat resistance and tensile strength are increased which increases the efficiency of the polymer.

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Biodegradable polymeric nanoparticles are highly regarded in drug delivery due to bioavailability, better encapsulation, controlled release and low toxicity. Drug encapsulation in polymeric nanoparticles may improve the therapeutic effects of these compounds. Polymers are divided in two types: natural and synthetic. Chitosan, as a natural polymer, can have many applications in drug delivery due to good properies. The purpose of this study is to optimization of the production of chitosan nanoparticles for drug delivery. Chitosan nanoparticles were prepared according to ionic gelation method and characterized. Prepared nanoparticle morphology investigated using SEM and particle size distribution, and surface charge and polydispersity index (PDI) were determined by Nanozeta Sizer. FTIR spectra of the lyophilized samples were recorded and proved the formation of nanoparticles. This study has shown that the particle size and zeta potential can be controlled by a change in the ratio of the weight and volume of chitosan and pH adjustment.

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The aim of this study, in the first step, was to recover the protein content in wastewater of fish meal factories using chitosan, chitosan nanoparticles and chitosan-aluminum sulphate composition. In the second step, the extracted protein was assessed for its  essential amino acids profile.  Also, the  reduced amount of proteins in the waste water was evaluated by measuring different parameters such as turbidity, pH, COD. Finally, chitosan nanoparticles characteristics were investigated using atomic force microscopy. Results showed that turbidity, COD and soluble protein significantly decreased upon  adding different concentrations of chitosan, nanoparticle of chitosan and chitosan-alum (p<0.05). The maximum protein recovery was related to chitosan-alum composition and chitosan nanoparticles with no significant difference between these two treatments. Evaluation of recovered protein in term of amino acids profiles showed that there were essential amino acids such as histidine, lysine, methionine and phenylalanine in protein of fish meal wastewater.      

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Silver nanoparticles (AgNPs) are widely used in consumer products mainly due to their antimicrobial action. The rapid increase in the use of nanoparticles has driven more attention to their possible ecotoxicological effects. In this study: first, acute effects of colloidal AgNPs during embryonic stage of Persian sturgeon and Starry sturgeon were investigated and then in Starry sturgeon, their short-term effects during early life stages (before active feeding commences) were analyzed. Based on the obtained results from the acute toxicity tests, AgNPs induced a dose-dependent toxicity in both species during early life stages. The short-term toxicity test was performed using 0, 0.025, 0.05 and 0.1 mg/l of colloidal AgNPs. Silver accumulation in larvae exposed to 0.1 mg/l AgNPs was recorded significantly higher than the control treatment (P<0.05). However, the obtained survival rate data did not indicate any significant differences among treatments.