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This study intends to take a new look at the application of NPs as a nanocomposite form for the first time to gain the most from the effects of them for EOR purposes. For this, ...TiO2/SiO2 and Fe3O4/SiO2 nanocomposites were first synthesized and investigated for EOR purposes by different experiments, including contact angle, interfacial tension (IFT), injected fluid viscosity, NPs retention in porous medium and carbonate sand pack floodings. The results showed that each NP and nanocomposite presents a distinctive behavior depending on the pressure of the porous medium, with all bringing higher oil production compared to that of seawater (SW) injection. At the ambient pressure, the dominant mechanism during TiO2 and TiO2/SiO2 nanofluid injection was found to be the IFT reduction along with wettability alteration. Whereas, at the intermediate pressure (1500 psi), the wettability alteration by TiO2 NPs and TiO2/SiO2 nanofluids was regarded to be the dominant EOR mechanism and recorded a recovery factor of 60 and 72%, respectively. At the high pressure (3500 psi), the dominant mechanism was observed to be asphaltene adsorption by Fe3O4 NPs and Fe3O4/SiO2 nanocomposites leading to the ultimate recovery factor of 56 and 69%, respectively. The highest incremental recovery for NPs was observed for tertiary injection of SiO2 nanofluid at 1500 psi, which increased the oil recovery by 14%. Whereas, Fe3O4/SiO2 and TiO2/SiO2 nanofluids increased the oil recovery by 24 and 23% at the pressures of 3500 and 1500 psi, respectively. This confirms the efficient role of the synthesized nanocomposites for improved oil recovery. Finally, the results of absorbance measurements of the inlet and outlet of the sand pack during Fe3O4/SiO2 nanofluid injection indicated a 32.4% NPs retention in the porous medium.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•NAOS forms a thin layer (2.36 nm) of SiO2 with high density (3.855 g/cm3).•NAOS-SiO2 (0.0581 A/cm2) is more effective in reducing leakage current density.•The phtotcurrent density of ...NAOS-SiO2/Si photoelectrode increased to −16.26 mA/cm2.•The photocurrent density improvement due to NAOS is equally reproducible.
This study presents the fabrication and comparative evaluation of SiO2/Si photoelectrodes employing two distinct SiO2 oxidation methods. Each SiO2/Si photoelectrodes was successfully generated based on uniform SiO2 layers a top nanoporous Si that have thicknesses of 2.7 nm via hydrogen peroxide oxidation (H2O2 oxidation) and 1.8 nm via nitric acid oxidation of Si (NAOS). Notably, the thin NAOS-formed SiO2 layer resulted in a measured suboxide density approximately 4.8 times lower (0.5192 × 1014 atoms/cm2) than that of the H2O2 oxidation (2.4969 × 1014 atoms/cm2). The presence of this SiO2 layer not only passivates defects but also improves electrical properties. As a result, the photocurrent density of the NAOS-formed SiO2/Si photoelectrode notably outperformed that of the H2O2-formed counterpart (about 1.7 times). This enhancement is attributed to the consistent passivation effects and improved electrical properties achieved due to NAOS-formed SiO2. This study contributes to a deeper understanding of how the SiO2 passivation layer can be utilized to improved photocurrent density.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Mixed powder of SiO2 and SiC was heated to produce Si in air by irradiating multi-mode microwave at 2.45 GHz using a porous alumina crucible of sintered cement. SiC generated heat inside the mixture. ...Mullite layer was produced inside of crucible wall. Molten Si was produced at the apparent temperature between 1550°C and 1600°C during 5400s and 6000s. The apparent temperature was much lower than 1778°C determined thermodynamically. This is the characteristics of microwave that heat generates at the contact points of particles and the pointed parts of the surface in powder. A furnace for producing high-quality Si by microwave heating is proposed.
The global shortage of solar grade silicon for the production of photovoltaic cells has motivated many researches on the refining of silicon, especially the refining of metallurgical-grade silicon. ...In order to obtain better control of the removal process of boron from molten silicon using silicate slags, precise thermodynamic data are required. In the present study the partition ratio of boron (LB) between the slag and silicon phases and the activity coefficient of boron oxide in CaO–SiO2, CaO–SiO2–25%CaF2, and CaO–SiO2–40%CaF2 slags were evaluated at 1823 K. The activity coefficient of BO1.5 was investigated for slags of CaO/SiO2 ratio varying from 0.3–7.0; further, the borate capacity of the slag is defined in this study as: Equation The addition of Na2O to CaO–SiO2 slags was found to increase the partition ratio of boron between the slag and the silicon phase.
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•Surface modification of SiO2 NPs is carried out to better dispersion in the polymer.•Several methods for the fabrication of PSNCs have been illustrated.•The most important properties ...of the PSNCs have been discussed.•Incorporation of SiO2 NPs in the polymer matrix tunes its properties for utilization.
At the present modern age, perhaps nanocomposites (NC)s are the most attractive materials which hold their situation in almost all of our life’s aspects. Among different kinds of the NCs, polymer based NCs are the most prominent one and have more adherents. Polymers are prepared via easily and relatively inexpensive routes, and have many favorable properties, such as light weight, ductility, and flexibility. The outstanding properties presented by the polymer/SiO2 NC (PSNC)s prompted us to focus particularly on them in this review. First, we briefly elucidate about the nano-building block of these NCs and its preparation methods. Afterwards, this review concentrates on the NCs’ fabrication strategies and finally the most important properties and the related practical applications which are newly presented will be discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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Drilling fluid is one of the most important components of drilling operation in oil and gas, mining and geothermal industries. Nanotechnology can be used to develop drilling fluid ...additives that can improve the drilling fluid properties. In this work, the feasibility of using two types of nanoparticle additives in water-based drilling fluid has been investigated. Clay/SiO2 nanocomposite was synthesized (by effective hydrothermal method) and successfully characterised. A series of experiments are performed to evaluate the effect of SiO2 and clay nanoparticles on the rheological and filtration properties of water-base drilling fluids. The experiments are conducted at different concentrations of Clay/SiO2 and SiO2 nanoparticles, and also at a range of temperatures. The results showed that the addition of clay and SiO2 nanoparticles improved the rheological and fluid loss properties. It was also noticed that the nanoparticles provide thermal stability to the drilling fluid. The experimental results suggest that the Clay/SiO2 nanoparticles have a more significant impact on the rheological and fluid loss properties of the drilling fluid comparing to SiO2 nanoparticles, particularly at higher temperatures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The combination of dielectric materials and magnetic composition and microstructural design have been demonstrated to be an ideal method for achieving efficient electromagnetic wave (EMW) absorption. ...Herein, Fe3Si/SiC/SiO2 composites constructed by magnetic/dielectric multi-component were successfully constructed via an ingenious carbothermal reduction strategy. Notably, the obtained Fe3Si/SiC/SiO2 composites at 1600 ℃ demonstrate the outstanding microwave absorption at an extremely low fill rate of 15 wt%, with the minimum reflection loss (RLmin) of −64.77 dB and an effective absorption bandwidth (EAB) of 5.53 GHz. The efficient absorption properties of Fe3Si/SiC/SiO2 composites are due to the magnetic-dielectric loss effect, and impedance matching. Porous structure also enhances impedance matching, thereby augmenting the absorption capabilities of the material. In summary, this research work introduces a novel strategy for the design of EMW absorbents with strong absorption in multi/low frequency band, wide absorption band and lightweight.
•A novel class of Fe3Si/SiC/SiO2 composites has been successfully synthesised.•Fe3Si/SiC/SiO2 composites can achieve excellent electromagnetic wave absorption through coupled dielectric-magnetic losses.•The rational regulation of components and structure was achieved by the carbothermal reduction reaction temperature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, a core-shell structural nano-composite material, namely CdTeS@SiO2, is synthesized by a simple silanization of Te-doped CdS quantum dots (CdTeS QDs). Through SiO2 capping, CdTeS QDs ...not only improve the fluorescence performance effectively, but also greatly enhance the anti-interference ability in the environment. Based on its excellent optical properties, a novel fluorescence sensor is constructed for the ultramicro detection of Ag+. The fluorescence of CdTeS@SiO2 is strongly quenched in the presence of Ag+ and shows good linearity in the range of 0.005–5.0 μmol L−1 with a detection limit as low as 1.6 nmol L−1. This is mainly due to its unique quenching mechanism: Ag+ destroys the spherical structure of SiO2 and promotes the formation of non-radiative electron-hole pairs through electron transfer, leading to fluorescence quenching. At the same time, it competes with Cd for Te, S and MPA on the CdTeS surface, forming Ag–Te, Ag–S and Ag–MPA complexes attached to the CdTeS surface leading to wavelength red-shift. The feasibility of the proposed sensor is demonstrated through spiking experiments, which confirmed the potential value of the constructed fluorescence probe for real-world applications in detecting Ag+ in environmental water.
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•Synthesis of CdTeS@SiO2 core-shell structures with high fluorescence properties.•The sensor exhibits high selectivity for Ag+ and has a low detection limit of 1.6 nmol L−1.•The phenomenon of Ag+ destroying SiO2 shells is revealed.•NIR-II spectra and fluorescence confirm the generation of Ag–Te and Ag–S complexes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The dehydration of ethanol into diethyl ether over a SO4/SiO2 catalyst was investigated. The SO4/SiO2 catalysts were prepared by the sulfation method using 1, 2, and 3 M of sulfuric acid (SS1, SS2, ...and SS3) via hydrothermal treatment. This study is focused on the synthesis of a SO4/SiO2 catalyst with high total acidity that can be subsequently utilized to convert ethanol into diethyl ether. The total acidity test revealed that the sulfation process increased the total acidity of SiO2. The SS2 catalyst (with 2 M sulfuric acid) displayed the highest total acidity of 7.77 mmol/g, whereas the SiO2 total acidity was only 0.11 mmol/g. Meanwhile, the SS3 catalyst (with 3 M sulfuric acid) has a lower total acidity of 7.09 mmol/g due to the distribution of sulfate groups on the surface having reached its optimum condition. The crystallinity and structure of the SS2 catalyst were not affected by the hydrothermal treatment or the sulfate process on silica. Furthermore, The SS2 catalyst characteristics in the presence of sulfate lead to a flaky surface in the morphology and non-uniform particle size. In addition, the surface area and pore volume of the SS2 catalyst decreased (482.56–172.26 m2/g) and (0.297–0.253 cc/g), respectively, because of the presence of sulfate on the silica surface. The SS2 catalyst's pore shape information explains the formation of non-uniform pore sizes and shapes. Finally, the activity and selectivity of SO4/SiO2 catalysts in the conversion of ethanol to diethyl ether yielded the highest ethanol conversion of 70.01% and diethyl ether product of 9.05% from the SS2 catalyst (the catalyst with the highest total acidity). Variations in temperature reaction conditions (175–225 °C) show an optimum reaction temperature to produce diethyl ether at 200 °C (11.36%).
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•The synthesis of SO4/SiO2 from TEOS was carried out using hydrothermal treatment.•Conversion of ethanol into DEE using SO4/SiO2 was higher compared to the SiO2.•SS2 catalyst produced the highest ethanol conversion and DEE yield at 200 °C.•The synthesis of SS2 catalyst via hydrothermal showed higher activity than sol-gel.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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