جستجوی مقالات مرتبط با کلیدواژه "Nanosilica" در نشریات گروه "شیمی"
تکرار جستجوی کلیدواژه «Nanosilica» در نشریات گروه «علوم پایه»-
The aim of this research was to determine the effect of nano silica and nano phosphate composition on characteristics of artificial insemination semen storage ampoules. The laboratory research used a factorial completely randomized design (CRD) consisting of two factors, namely the measurement day factor consisting of 21 treatments (day 1 to 21) and the measurement time factor consisting of two treatments (day and night), each repeated three times. The variables studied included temperature (oC), humidity (%), and water content (%). Nanostructure characterization was carried out using FTIR, XRD, SEM-EDX measurements. The nano silica gel from silica powder from rice husk ash resulted in particles with an average size of 23.65 ± 1.0 nm. These particles were homogeneous, containing only Si-O bonds, in the form of an amorphous SiO2 phase. The nano calcium phosphate was obtained from hydroxy apatite previously isolated from cattle bone waste. It had an average size of 43.39 ± 1.0 nm, was homogeneous, and contained Ca-O, P-O, P=O, O-H bonds, in the form of an amorphous phase Ca3(PO3)2. The calcium silicophosphate gels exhibited homogeneous particle sizes with an average size of 36.98 ± 1.0 nm of Si/P =1. Their particle sizes increased by decreasing Si/P values and decreased by increasing Si/P values significantly. These gels contained Ca-O, P-O, P=O, O-H, Si-O, Si-O-P bonds in the form of amorphous or glacial CaxSiPOy phases. Additionally, the nano silica gel demonstrated a sensitivity to absorb and release water from and to its surrounding environment.Keywords: Nanosilica, Nanophosphate, Nanoparticle, Semen Storage Ampoules, Artificial Insemination
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The impact of adding nanosilica (NS) and polycarboxylate-ether plasticizer (PCE) admixtures was examined individually and in combination to aerial lime mortars. The inclusion of NS alone resulted in an increase in water demand, as evidenced by the mini-spread flow test. Through particle size distribution studies, zeta potential measurements, and optical microscopy, it was observed that an interaction occurred between NS and hydrated lime particles in fresh mixtures, leading to the formation of agglomerates. This synthesis was performed at three different temperature levels, and the resulting product underwent FTIR analysis to verify its structure. Furthermore, an HNMR test was conducted to confirm the completion of the final synthesis. To determine the characteristics of the synthesized polycarboxylate ether, including the average molecular weight and molecular weight distribution curve, a GPC analysis (Gel permeation chromatography) was carried out. The MW and PDI (polydispersity index) values were reported, and finally, a slump test was performed to confirm the performance of the synthesized product. The length of the main chain in the copolymer increases as the synthesis temperature rises. This increase is more pronounced at higher temperatures. However, temperatures exceeding 70 C can lead to the destruction of the copolymer, resulting in a decrease in viscosity and a change in the solution color. Therefore, it is recommended to carry out the primary synthesis at 70 C for 8 hours.Keywords: Superplasticizers, Polycarboxylate Ether, Solution Synthesis, Nanosilica
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In the current research sodium silicate has been used to synthesize silica colloid by ion exchange process. Deterministic relations for zeta potential, size and solid content have been developed by optimization of three input parameters: seed concentration (0, 1, 2%wt), temperature (30, 55, 80°C) and KOH concentration (0.5, 1, 1.5%wt). Central Composite Design of Response Surface Methodology was used to optimize silica colloid. The goal of this optimization is to achieve the silica colloid with the highest zeta potential, the minimum particle size and the highest solid content. The derived equations and contour plots predict the values of selected independent variables for preparation of optimum silica colloid with desired properties. Based on the fitted models, the optimum silica colloid is prepared by 0.756%wt KOH in 70°C that contains 59.9 %wt SiO2. Also, this silica colloid sample contains a particle size of 11.5 nm and zeta potential of -6.48 mV.Keywords: nanosilica, Seed, response surface methodology, Silicacolloids
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Corrosive environment can significantly effect on the mechanical behavior of composite structures which can improve by using hydrophobic nanoparticles. The aim of this study is to investigate the improvement of the mechanical properties of incorporated glass fiber reinforced polymer (GFRP) composite specimens with 3 wt. % of nanoclay and nanosilica in a corrosive environment. Filled GFRP composites were fabricated using the mechanical stirrer following by sonication method, and the hand layup method. After preparing the neat and incorporated GFRP according to ASTM standards, all the samples were immersed in 5% sulfuric acid solution for 0, 1, and 3 months. As the immersion time increased, the samples containing nanosilica absorbed more water than the other samples. The tensile and compressive tests were performed at different immersion times to obtain the ultimate tensile and compressive strength and tensile modulus. The results showed that by adding nanoparticles, the mechanical properties were increased, which GFRP containing nanoclay showed a better behavior in the corrosive environment. By adding 3 wt. % of nanoclay, the ultimate tensile and compressive strength and the tensile modulus decreased after one month of immersion by only 0.34%, 1.81% and 2.95%, respectively, and after three months of immersion only decreased by 0.43%, 10.88% and 6.95%, respectively. Finally, SEM images of all specimens were examined to investigate the fracture mechanisms and the corrosion behavior of fabricated nanocomposites.Keywords: Glass fiber reinforced polymer (GFRP) composites, nanosilica, Nanoclay, Mechanical Properties, Corrosive environment
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امروزه MCM-41 عاملدار شده با آمینو پروپیل با داشتن مساحت سطح بالا، به عنوان یک سیستم بالقوه تحویل داروهای ضد سرطان معرفی شده است. در این تحقیق به منظور تولید یک سیستم تحویل داروی هدفمند مبتنی بر تصویر برداری در کاربردهای تشخیصی، پروتو پورفیرین با رادیو نوکلیید گالیوم-67 نشاندار و سپس این کمپلکس بر روی NH2-Propyl@MCM-41 تثبیت شد. از تکنیک های رادیو کروماتوگرافی لایه نازک RTLC، پراش اشعه ایکس، طیف سنجی FT-IR، آنالیزهای جذب و واجذب گاز نیتروژن و TGA/DSCبرای شناسایی نانوذرات استفاده شد. ارزیابی فارماکوکینتیکی نانوسیلیکای نشاندار رادیواکتیو 67Ga-PP IX...NH2-Propyl@MCM-41 در موش های صحرایی نرمال و دارای تومور فیبروسارکوما انجام شد. این نانوکامپوزیت دارای خواصی نظیر گردش مناسب در بدن از طریق خون، پایداری ساختاری بالا، درصد جذب ID مناسب در تومور، نسبت بالای جذب تومور به ماهیچه و دفع سریع از بدن بوده و به عنوان یک ترکیب مهندسی شده موثر برای کاربردهای آتی رسانش هدفمند و تصویر برداری از تومور مبتنی بر نانوتکنولوژی در مطالعات آتی پیشنهاد می شود.
کلید واژگان: کمپلکس نشاندارسازی شده پورفیرینی, نانوسیلیکا, 41-MCM, تصویربرداری هسته ایNowadays, aminopropyl functionalized mesoporous silica MCM-41 is known as a potential anticancer-drug delivery system with a high surface area. In this work, so as to produce an image-guided drug delivery system for diagnostic applications, proto porphyrin was radiolabeled with 67Ga radionuclide and this complex was grafted on 3-aminopropyl functionalized MCM- 41. The nanoparticles were assessed with radio thin layer chromatography RTLC, X-ray diffraction, FTIR spectroscopy, surface area analysis BET and ThermogravimetrY.
Keywords: labeledporphyrincomplex, nanosilica, MCM-41, nuclearimaging -
بدون شک سیلیکا را می توان به عنوان یکی از نانوذرات مهم و پرکاربرد در پالایش محیط زیست در نظر گرفت که تاکنون بیشترین تحقیق و بررسی در مورد آن انجام گرفته است. در حال حاضر طیف گسترده ای از محصولات بر پایه نانوذرات سیلیکا برای کاربرد های مختلفی از جمله الکترونیک، پزشکی و داروسازی و غیره تولید می شوند. اما پاک سازی و پالایش محیط های آلوده، آرمانگرایانه ترین نوع استفاده از نانو سیلیکا ها می باشد و اخیرا، کاربرد آنها در تصفیه آب و فاضلاب مورد توجه زیاد پژوهشگران قرار گرفته و این کاربرد روز به روز در حال توسعه و گسترش می باشد. به دلیل مساحت سطحی بسیار زیاد، نانوذرات سیلیکا از ظرفیت جذب و واکنش پذیری ویژه بالایی برخوردار است. مطالعات اخیر نشان داده است که نانوذرات سیلیکای آب دوست و آب-گریز برای حذف آلاینده هایی همچون رنگزاها، انواع فلزات و سموم دفع آفت از آب و فاضلاب بسیار کارآمد است. مزیت جالب دیگر نانوذرات سیلیکا به عنوان جاذب این است که غیر سمی اند و به محیط زیست آسیبی نمی زنند. علاوه براین فناوری های برپایه نانوسیلیکا از نظر اقتصادی نیز به دلیل قیمت نسبتا پایین فرآورش مواد خام بسیار جذاب و قابل توجه است. در این مقاله پیشرفت های اخیر در زمینه پاکسازی و پالایش محیط زیست از طریق حذف آلاینده ها از محیط زیست توسط نانوذرات سیلیکا به همراه روش های سنتز این نانوذرات مهم و پرکاردبرد بررسی شده است.
کلید واژگان: نانوذرات, نانوسیلیکا, محیط زیست, پاکسازی و تصفیهA Quarterly Publication The Application of Chemistry in Environment, Volume:10 Issue: 38, 2019, PP 47 -60Environmental remediation deals with the removal of contaminants from environment for maintaining and restoring the quality of soil, water, and air and, more in general, for protecting human health. At present, a wide range of silica products is manufactured for applications in microelectronics, medicine, pharmacy and so on. A more ambitious use of nanosilicas is remediation of contaminated environments and, recently, their application in wastewater treatment has emerged as a fast-developing and attractive area of interest. Because of high surface area, silica nanoparticles show a very good adsorption capacity and a large specific reactivity. Recent studies have shown that hydrophilic and hydrophobic silica nanoparticles are very efficient in removing pollutants such as dyes, metallic species, and pesticides from water, and wastewaters. Another interesting benefit of silica nanoparticles as adsorbents is that they are considered non-toxic and not harmful to the environment. Moreover, nanosilica based technology shows an attractive cost-effectiveness ratio as it requires relatively cheap processing of raw materials. This paper has reviewed the recent progresses in remediation by silica nanoparticles and their synthesis methods.
Keywords: nanoparticles, nanosilica, environment, Remediation -
International Journal Of Nanoscience and Nanotechnology, Volume:14 Issue: 3, Summer 2018, PP 187 -195High strength and elastic biodegradable membranes are of great demand in modern technology. Similar membranes have been developed by irradiating different weight poly (vinyl alcohol) (PVA) hydroxypropyl guar gum (HPG) blends and followed by combining with ex situ nanosilica. Polarized light microscopic (PLM) study indicates that electron beam irradiation produced crosslinks and developed crystallinity in PVA-HPG matrix. Atomic force microscopic analysis shows that 1 wt.% nanosilica produced finer dispersion in both high and low molecular weight PVA-HPG matrix resulting nearly 4.5 times higher mechanical strength and controlled swelling-deswelling property e.g., low molecular weight PVA with 1wt% nanosilica content show swelling ratio 3.5. Greater nanosilica and PVA-HPG interaction was observed in low molecular PVA-HPG composite membranes than high molecular weight PVA-HPG composite membranes which finally showed better efficacy towards drug retention and elution under physiological conditionKeywords: Polymer, Irradiation, Membrane, Nanosilica, drug delivery
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Phosphosulfonic acid as a multi solid site was easilyprepared from the reaction of ammonium dihydrogen phosphatewith chlorosulfonic acid in CCl4and for improved its catalyticactivity was supported nano Silica was extracted from husk ricecontains about 95% of Silica the size of extracted nano silica wasdetermined by SEM efficiency of this solid acid in four componentcondensation reaction of aromatic aldehydes, dimidone, diketon, anammonium acetate was investigated the results were clearlyshown that aldehydes having electron withdrawing and electrondonating groups were efficiently converted to the correspondingPolyhydroqinilion the high yields and short time products wereproduced at 110 0C under solvent free conditionsKeywords: nanosilica, Phosphosulfonic, Polyhydroquinolin, Hantzsh, Condensation
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To date, the effects of nanoparticles on woody plants remain unaddressed. This study reveals some of the physiological and biochemical effects of SiO2 nanoparticles on wild pear seedlings. The seedlings were irrigated with different concentrations of nano silica (0, 10, 100, 500 and 1000 mg/l) for 14 days. Nanoparticle adsorption and absorption, biomass allocation, gas exchange, relative water content, xylem water potential, electrolyte leakage, pigment and proline content, antioxidant enzymes, and nutrient cycles were surveyed. The attachment of nanoparticles on the root surface was observed by scanning electron microscopic and the accumulation of Si in leaves was measured by X-ray fluorescence analysis. Although the performed experiments did not show any acute toxic effects of adding of SiO2 nanoparticles in irrigation to wild pear plant, the finding should be confirmed with other experiments of longer duration and high exposure concentrations before a final conclusion in this issue can be made.Keywords: Nanoparticles, Nanosilica, Toxic effect, Woody plants, Physiological, biochemical parameters
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International Journal Of Nanoscience and Nanotechnology, Volume:10 Issue: 3, Summer 2014, PP 145 -152Colloidal nanosilica is currently being produced by various methods which are mainly high energy intensive and/or not environmentally friendly. It is therefore essential to develop new energy efficient and environmentally friendly technologies. This paper introduces a new ultrasound assisted route based on alkali leaching of silica fume for synthesis of colloidal silica nanoparticles. The effects of sonication time on the particle size distribution of the colloidalnanosilica are studied via dynamic light scattering (DLS). The results show that the shape and size of nanoparticles are strongly depended on the ultrasonic time. DLS results show that average diameter of the produced colloidal nanosilicadecreases sharply from 337.10 nm to 93.27 nm during the first 5 minutes of sonication. Continued sonication up to 30 minutes, however, shows relatively slight decrease in average diameter of the colloidal nanosilica. Further, the produced colloidal nanosilica is characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy.Keywords: Nanoparticles, Nanosilica, Colloid, Silica fume, Ultrasound
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Polyacrylonitril (PAN)-supported chitosan (CS) nanocomposite membranes were prepared by cross-linking the CS with 3-aminopropyl-triethoxysilane (APTEOS) via sol-gel method. Pervaporative performances of the CS-SiO2/PAN membrane for dehydration of aqueous alcohol solutions were investigated. From SEM cross-sectional images of the membrane, the spongy pores and the finger-like pores were found in cortex and intermediate layer. The PAN microporous substrate and the top layer were about 100 and 7.4 µm thick, respectively. The separation factor and permeation flux of the synthesized CS/PAN and CS-SiO2/PAN membranes indicated that introducing 5% of nanosilica to skin layer of the composite membrane improved its pervaporative properties. At 30, a separation factor of 20.03 and 34.25 were achieved for CS/PAN and CS-SiO2/PAN membranes, respectively.Keywords: chitosan, 3, Aminopropyl, triethoxysilane, Nanosilica, Nanocomposite membrane, Pervaporation
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Phosphosulfonic acid as an soild acid supported on nanosilica extracted from rice husk in Polyhydroqinilion SynthesisPhosphosulfonic acid as a multi solid site was easily prepared from the reaction of ammonium dihydrogen phosphate with chlorosulfonic acid in CCl4and for improved its catalytic activity was supported nano Silica was extracted from husk rice contains about 95% of Silica the size of extracted nano silica was determined by SEM efficiency of this solid acid in four component condensation reaction of aromatic aldehydes, dimidone, diketon, an ammonium acetate was investigated the results were clearly shown that aldehydes having electron withdrawing and electron donating groups were efficiently converted to the corresponding Polyhydroqinilion the high yields and short time products were produced at 110 0C under solvent free conditions.Keywords: nanosilica, Phosphosulfonic, Polyhydroquinolin, Hantzsh condensation
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