Nanosilica Solution Research Articles

The Effects of Nano-Based Bio-Carbonates in Superhydrophobic Concrete—A Review

Concrete must be a hydrophilic compound that is easily fabricated by nature. At the nanoscale, mechanical and chemical reactions alter the quality of cement-based substances. Continuous sprinkling of nano-silica solution synthesised with minimal surface solvents has been used to create a superhydrophobic (SH) concrete surface while similarly modifying the surface’s chemical composition and dynamical intrinsic structure. In this study, we examine the impacts of admixtures in SH concrete including nano-based bio-carbonate. The fundamental characteristics and dispersal techniques of nanoparticles often employed in cement-based compounds are reviewed initially in this paper. Investigations of the large contact angle, small slide angle, and carbonated thickness have been employed to analyze the impacts of admixtures. Additionally, the industry and uses of nanoparticles for concrete substances are addressed, and the expense is inventively represented by a survey questionnaire. Finally, this article identifies the obstacles that now occur in the field of research and offers appropriate future viewpoints.

Flow behavior of nano-silica solutions in cement cracks/fractures

One of the most prevalent causes of failure in oil and gas wells is the formation of cracks in the wellbore cement. The cracks can lead to loss of zonal isolation and fluid leakage to the surface. Compared to cement slurry which is difficult to squeeze into the cracks due to its high-solid content, nanoparticle (NP) gels have gained significant attraction for sealing fractures/cracks in oil and gas wells. It is highly desirable to know the flow behavior of NP solutions in the cracks. This study investigated the flow of nano-silica solutions through narrow rectangular cross-sections simulating sealant flow in cracks of oil well cement sheath. Pressure gradient was tested at 4 flow rates for various aspect ratios of the rectangular cross-sections. For a given cross-section of conduit, pressure drop increased with flow rate. For a given conduit height, the pressure drop decreased with conduit width due to increased flow area. Pressure drop increased as the conduit height reduced. These characteristics of nan-particle solution flow are like those found for conventional fluids. The pressure gradient of nano-silica solution flow in a conduit of a given rectangular cross-section is nearly proportional to flow velocity at tested flow rates, indicating laminar flow conditions in the tested flow conditions. The proportionality factor (rate of increase) increases as the aspect ratio of the cross-section decreases (slot becomes narrower). This is because a system with a lower aspect ratio has four boundaries that generate a 2-dimensional velocity profile, while a system with a higher aspect ratio has essentially two boundaries that generate a 1-dimensional velocity profile. More boundaries mean more frictional resistance to fluid flow. Hydraulics models for conventional fluid flow through conduits of rectangular cross-sections under-predict the pressure gradient of nano-silica solution. The discrepancy/difference is over 90% in pressure gradient prediction in general. The hydraulics model presented by Guo et al. (2022) with aspect ratio is better than the classical hydraulics model with hydraulic diameter. However, both models fail to predict the pressure gradient along the conduits with slot-like cross sections. The excessive pressure drop is attributed to the interactions between the nano-particles and conduit walls. Further investigations are required to gain a thorough understanding of nano-silica flow.

Investigation of Nano-Silica Solution Flow through Cement Cracks

Cement cracks are one of the most common failures in oil and gas wells. Cracks can reduce cement strength, resulting in a loss of zonal isolation and fluid leak. Placement of gels of nanoparticles (NPs) in the cracks is considered as a promising solution to solve the problem. It is highly desirable to know if the flow behavior of the NPs solutions is predictable when they are squeezed into the cracks. Experimental tests were performed in this study to investigate the flow behavior of nano-silica solutions in ducts of cross-sections of rectangular shape. The linear relationship between flow rate and pressure gradient and the calculated Reynolds number values suggests laminar flow in the ducts. However, the Hagen–Poiseuille correlation for laminar flow does not describe the flow behavior of the nano-silica solution. The classic hydraulic model with hydraulic diameter describes the nano-silica flow behavior with an average error of 12.38%. The cause of discrepancies between the flow models and the measured data is not known. It can be attributed to the NPs–NPs frictions and NPs–wall frictions in the rough ducts that were not considered in the flow models.

Experimental Investigation of Nanosilica Gel Properties for Well Integrity Remediation

This study investigates the role of clay mineral, polyacrylamide additive, and nanosilica solution in the creation of a cross-linked gel for well cement repair. Several experimental setups were developed using a rotational viscometer and an Anton rheometer to investigate the impact of nanosilica particles on the rheology and performance prediction of the sealing gel. The results of varying the nanosilica concentration revealed that silica solution with a concentration of 15–25 wt % produced a lower gel strength property over a suitable gelation period, whereas silica solution with a concentration of 30–40 wt % displayed a higher gel strength property but with a short gelation time. The findings also demonstrated that adding 0.15 wt % polyacrylamide (PAM) to 18 wt % nanosilica significantly enhanced the properties of the gel, increasing about 135% in the gel strength, 429% in the yield point, and 122% in the storage modulus without posing any operational issues. The gelation of the nanosilica solution in the downhole environment, on the other hand, was shown to be greatly improved by the clay mineral bentonite, which was present in the formation rock. This research’s findings have improved the oil and gas industry’s understanding of the materials that might be used to improve a sealing gel’s rheological properties for well integrity operations.

THE SYNERGIZATION OF SILICA NANOPARTICLE AND SODIUM DODECYL SULFATE FOR CHEMICAL FLOODING APPLICATION

Nowadays, enhanced oil recovery is vital in improving the oil recovery. However, the oil productions keep depleting due to production problem such as high surface tension and interfacial tension reservoirs. Therefore, chemical flooding is one of the methods used in enhanced oil recovery. The synergy between Silica nanoparticle and Sodium Dodecyl Sulfate has been proposed as a compound for chemical flooding in enhanced oil recovery in this project. The major aim of this study was to measure the effectiveness of synergization between Silica (SiO₂) nanoparticles SDS with different injection ratio by measuring the oil recovery using chemical flooding. After the synergization of surfactant with nanosilica solution take place, the surface tension and interfacial tension test have been conducted to identify the optimum concentration. The results showed that the optimum concentration for SDS is 2000 ppm with surface tension (ST) and interfacial tension (IFT) are 33.5 and 36.0 mN/m respectively. When the SiO₂ nanoparticles were added, it showed that 6000 ppm was the optimum concentration with reduction in surface tension and IFT to 31.0 and 34.5 mN/m respectively. The 20,000 ppm brine and paraffin oil have been injected into the sandpack followed by waterflooding and chemical flooding. The results from the experiment presented that the oil recovery for waterflooding were in between 23% to 28% therefore, more oil left in the sandpack. Then, surfactant with nanosilica solution was injected with 20,000 ppm of brine as a slug with injection ratio in between 0.1 to 0.5 as tertiary recovery. It showed that the oil recovery increases up to 48% for 0.1 of injection ratio and 64% for 0.5 injection ratio. As a conclusion, it is proved that the synergization of SiO₂ nanoparticle and SDS is applicable for chemical flooding as tertiary recovery because in can recover up to 64% of oil production.

Investigation on Mechanical Properties of Cementitious Composites cured in colloidal Nanosilica SiO2 solution.

Nano technology is one of the most widely searched techniques in the world nowadays. Several studies reported with nanoparticles are based on the nano-silica (nano-SiO2) addition to the fresh mix to improve the performance of concrete. Nano-SiO2 is highly reactive with calcium hydroxide and is able to act not only as a filler, blocking the concrete pores, but also as an activator to promote pozzolanic reaction. In this study, the effect of different concentration of nano silica solution on concrete compressive strength when using it in curing instead of water. Samples were made by adding fly ash (FA/PC= 1.2 and 2.2) and some were immersed in water and others in a suspension containing water with Nano SiO2 with different concentrations (0.5, 1, 2 and 3) %. Then submit the samples to compression test after 3, 7 and 28 days to notice the impact of using Nano silica solution in curing stage. Fly ash has been used in this experiment for several reasons. 1. Development of the mechanical properties of the cement-bonded composites. 2. Reduces the percentage of cement use and therefore we will keep the environment clean because the cement reaction produces CO2 which cause polluting to the environment.

Mechanical and permeability properties on self‐healing of cementitious composites effect of nano silica cure

AbstractThe self‐healing behavior of concrete elements with high risk of crack formation under various conditions from the moment of production has become a very important issue. In this study, the effectiveness of nano silica (NS) curing solutions in terms of self‐healing behavior in engineered cementitious composites (ECC) was investigated. For this purpose, precuring was applied to the cementitious composite mixture prepared with four different contents for 7, 28, and 90 days and then half of the specimens were exposed to damage to certain extents of the mechanical strength loads. Half of the specimens were left in a 2% solution of NS for a further period of 7, 30, 60, and 90 days, and another portion was left in curing only in water (W). The mechanical properties of the sound and preloaded specimens were investigated with compressive and flexural tests, and the improvements in permeability were investigated with the help of water absorption and sorptivity tests. As a result of the experimental studies, it was observed that the nano silica solution applied to the specimens during the curing phase caused a more effective and rapid healing in the mechanical and permeability properties of the composites when compared with the water curing.

Effects of Different Strain Rates on the Impact Properties of Recycled Aggregate Concrete Modified With Nanosilica Solution and Polyvinyl Alcohol Fiber

The recycled aggregate (RA) was modified by 2% nanosilica solution, and the split Hopkinson pressure bar (SHPB) test device was used to study the dynamic impact properties of the modified recycled aggregate concrete (RAC) mixed with polyvinyl alcohol (PVA) fibers. The RA replacement percentage, the amount of PVA fiber, and the strain rate were variables. The failure pattern, the stress–strain curve of the nanosilica solution, and PVA fiber-modified RAC were shown under different strain rate conditions. Dynamic peak stress, peak strain, and dynamic increase factor (DIF) of the specimens are discussed. The results showed that the stress and dynamic peak strain value of the specimen increased with the increase of the strain rate; moreover, with the increase of the RA replacement percentage and the PVA fiber content, the dynamic peak stress of the specimen decreases, while the dynamic peak strain and the DIF value increase. The incorporation of nanosilica-modified RA is beneficial to the improvement of the impact performance of RAC, and the incorporation of an appropriate amount of the PVA fiber effectively improves the deformability of RAC.

Stabilisation of peat with colloidal nanosilica

Colloidal nanosilica hydrosols are electrochemically stabilised polymerised amorphous silica in low viscosity suspensions. They have no known adverse impact on soil health and ecosystem service functions, thereby having a scope for use in groundworks as an alternative low-viscose stabilising material. Six grades of colloidal nanosilica are synthesised through an in-house procedure and introduced to a natural peat soil. The peak and residual compressive strength of compacted and modified soils are measured immediately after treatment and in four strain levels post treatment. Findings suggest that, despite the direct correlation between the nanosilica content and compressive strength, an increase in nanosilica content does not necessarily offer stability at larger strains. This is a major limitation. The particle-level kinematics in modified peat is discussed to gain a new insight into the role played by silica flocs on the build-up of macro-mechanical quantities such as peak and critical state strength. Overall, modification of peat with nanosilica leads to improvements in strength and formation of composites with generally more dilative behaviour. When used as a single stabiliser, a design 15 % to 20 % grade nanosilica solution yields a reasonably high strength although precautions against excessive straining of modified peat soils need to be taken in the first seven days post treatment. At this optimum grade, the loss of strength on further straining is capped to 9 % at plastic strains 1.5 times the peak strain.

The Acute Toxicity of SiO2 and Fe3O4 Nano-particles on Daphnia magna

SiO2 nano-particles are applied in different industries such as ceramic producing, glass making, cosmetic products, medicines, magnetic mixtures, heat and electric insulators and glazing currently. Also, nano particles of SiO2 can be utilized to increase the strength and stability of industrial coverings. Fe3O4 nano-particles enjoy pretty special and unique features compared to bulk Fe3O4 in terms of ultra-magnetic features, size and quantum feature. These nano-particles that are considered as one of the most important elements of iron-based mixtures, soft magnetic materials, record-player sets, colorful materials, magnetic suspended materials, magnetic vibrant recording in tissues recuperation and molecules diagnosis are highly used in pharmacy and biotechnology. With the development and progress of nano technology and increasing use of engineered nano-particles and besides all the benefits of nano particles; potential pollution of nano-particles should be considered that may occur after their transportation and entery into water environments. The aim of this research is to investigate the toxicity effect of SiO2 and Fe3O4 nano-particles on Daphnia magna that is regarded as a kind of hard zooplankton in fresh water and is as main aquatic ecosystem food chain after phytoplankton groups. In this test, OECD (Organization for Economic Cooperation and Development) method (202) was used and the toxicity effect of Fe3O4 and SiO2 nano-particles on Daphnia magna during 96 h was investigated. The daphnia had exposure to 6-treatments of nano silica solution, 5 treatments of nano iron oxide with three replications for each in comparison with control group. LC50 of silica and iron oxide nano particles were analyzed by probit data analysis method for the determination of Daphnia magna proportion in each solution following 96 h and respectively the following amounts of 1.73 and 654.65 mg/l were observed. The results of the study showed the lower rate of toxic effect in iron oxide nanoparticles compared to nano silica in Daphnia magna.

Metabolic Status during Germination of Nano Silica Primed Zea mays Seeds under Salinity Stress

Priming is a safe, easy, and effective way to increase plant tolerance against stress. This research aims to study the metabolic status of the nano-silica-primed germinated maize seeds under salinity stress. We prepare the nano-silica solution (10 mg/ml) from rice straw. We primed group maize seeds with nano-silica solution and the other group remained dry. The two seeds group germinated under different concentrations of NaCl (0, 50, 150 mM). Nano-silica primed seeds showed a higher germination rate and seedling vigor index. Priming helps the maize seeds to germinate under salinity stress through increasing the antioxidant enzymes activity which in turn suppresses the increase in the reactive oxygen species and so decreases the lipid peroxidation. Also, priming increases the gibberellin content and therefore activates the amylase and lipase activities which ensured the availability of the simple compounds needed for energy releasing through respiration. Besides that, priming enhances the activity of the respiration enzymes such as aldolase and iso citrate lyase. Finally, nano-silica priming enhanced the metabolic status of maize seeds under salinity stress.

Strength Properties of Nano Silica Recycled Sustainable Concrete

This experiment highlights the salient features of concrete under nanotechnology. Concrete production requires huge amount of cement and aggregates which eventually increases carbon emission and contaminates environment. Hence, incorporation of ‘F’ class fly ash which is partially replaced for cement, recycled aggregate and cactus gel can be done which can reduce dumping issues, carbon emission and cost. However, incorporation of fly ash in ordinary Portland cement deviates its strength consequently. Hence, Nano-silica can be added as an additive to fill up the deviation, thereby increasing its workability and improving the strengthening factor of concrete. In this paper mineral admixture such as Nano-silica were used to increase the strength of concrete and natural polymer substances such as cactus jelly is used to increase the workability of concrete. For the binding material cement were replaced with the fly-ash at the percentage of 60% respectively and for the coarse aggregate quarry aggregate has been replaced with recycled aggregate with the proportion of 40% and 60% respectively. In the investigation three specimens were casted say conventional, replacement of 60% and replacement of 60% with Nano silica and cactus extract solution. The result of compressive and flexural strength were compared. The aim of this experiment is to maintain the economy and environmental effect.

NANO SİLİKA KÜR UYGULAMASININ ÇİMENTO BAĞLAYICILI KOMPOZİTLERİN DONMA-ÇÖZÜLME DİRENCİ ÜZERİNE ETKİSİNİN ARAŞTIRILMASI

Bu çalışmada nano silica solüsyonunda kür etkisine maruz bırakılan çimento bağlayıcılı kompozitlerin (ECC), donma-çözülme döngüleri gibi ağır çevresel koşullar altında gösterdikleri direnç araştırılmıştır. Bu amaçla iki farklı tip uçucu kül iki farklı oranda kullanılarak dört farklı karışım olarak hazırlanan ECC numuneleri, ASTM C666 ProsedürA’ya uygun olarak 300 donma-çözülme döngüsüne maruz bırakılmıştır. Numunelerin mekanik özelliklerindeki değişimler basınç ve eğilme testleri ile, fiziksel özelliklerindeki değişimler ise, 30 çevrimde bir ağırlıklarının ölçülmesi ile belirlenmiştir. Çalışma neticesinde elde edilen sonuçlar, çimento bağlayıcılı kompozitlerde nano silica (NS) kür uygulamasının, zorlayıcı çevresel koşullar altında numunelerin dayanım ve dayanıklılık gibi özelliklerinde suda kür uygulamasına göre kayda değer artışlar sergilediğini göstermiştir.

Establishment and characterization of a multi-purpose large animal exposure chamber for investigating health effects.

Air pollution poses a significant threat to the environment and human health. Most in vivo health studies conducted regarding air pollutants, including particulate matter (PM) and gas phase pollutants, have been either through traditional medical intranasal treatment or using a tiny chamber, which limit animal activities. In this study, we designed and tested a large, whole-body, multiple animal exposure chamber with uniform dispersion and exposure stability for animal studies. The chamber simultaneously controls particle size distribution and PM mass concentration. Two different methods were used to generate aerosol suspension through either soluble material (Alternaria extract), liquid particle suspension (nanosilica solution), or dry powder (silica powder). We demonstrate that the chamber system provides well controlled and characterized whole animal exposures, where dosage is by inhalation of particulate matter.

Chloride Resistance of Nanoparticle Repaired Concrete Measured by Accelerated Tests

This paper describes results of experimental investigation of chloride ion penetration in concrete. Chloride concentration have been studied in accelerated conditions. Part of concrete samples were treated with colloidal nanosilica solution to increase their resistance to further chloride penetration. Measurement of chloride profiles was performed and compared on samples subjected to accelerated electrical migration tests lasting for a few days. The chloride ion profile in samples was determined in layers of 5 mm thickness up to a total profile thickness of 45 mm. The developed chloride concentrations reached values found after several years of exposure in natural conditions. It was found that the resistance to chloride penetration is substantially improved by nanosilica injection and the resistance to chloride penetration is increased by 60%.

Fast and excellent healing of hydroxypropyl guar gum/poly(N,N‐dimethyl acrylamide) hydrogels

ABSTRACTIn this article, a fast and high efficient healing hydroxypropyl guar gum (HPG)/poly(N,N‐dimethyl acrylamide) (PDMA) hydrogel is prepared by a facile synthesis method. HPG networks are formed through hydrogen‐bond interaction between the hydroxyl groups in the HPG chains, and PDMA networks are self‐crosslinked without any chemical crosslinker. The cut hydrogel could heal when nanosilica solution is chosen as the connector that is related to the adsorption of polymer to the surface of nanosilica. The fracture stress of the HPG/PDMA gels presents a fast and almost full recovery within a short time (1 min), while the recovery of fracture strain and elastic modulus is related to time in 2 h. The healing efficiency of HPG/PDMA gel is investigated as a function of healing time, HPG content, and N,N‐dimethyl acrylamide content. The microscopic healing process and healing mechanism are also discussed. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 239–247

Durable superhydrophobic surfaces made by intensely connecting a bipolar top layer to the substrate with a middle connecting layer

This study reported a simple fabrication method for a durable superhydrophobic surface. The superhydrophobic top layer of the durable superhydrophobic surface was connected intensely to the substrate through a middle connecting layer. Glycidoxypropyltrimethoxysilane (KH-560) after hydrolysis was used to obtain a hydrophilic middle connecting layer. It could be adhered to the hydrophilic substrate by covalent bonds. Ring-open reaction with octadecylamine let the KH-560 middle layer form a net-like structure. The net-like sturcture would then encompass and station the silica particles that were used to form the coarse micro structures, intensely to increase the durability. The top hydrophobic layer with nano-structures was formed on the KH-560 middle layer. It was obtained by a bipolar nano-silica solution modified by hexamethyldisilazane (HMDS). This layer was connected to the middle layer intensely by the polar Si hydroxy groups, while the non-polar methyl groups on the surface, accompanied by the micro and nano structures, made the surface rather hydrophobic. The covalently interfacial interactions between the substrate and the middle layer, and between the middle layer and the top layer, strengthened the durability of the superhydrophobic surface. The abrasion test results showed that the superhydrophobic surface could bear 180 abrasion cycles on 1200 CW sandpaper under 2 kPa applied pressure.

Effect of mixing methods of nano silica on properties of recycled aggregate concrete

The effect of presoaking of recycled coarse aggregate (RCA) in nano silica (NS) solution on the properties of recycled aggregates concrete is compared with the direct mixing of NS in concrete. In this study, four series of concrete are considered. The first and second series are control series containing 100% natural coarse aggregate (NCA) and 100% RCA, respectively. The third and fourth series are similar to the second series in every aspect except that 2 wt% NS is added through direct mixing in concrete and presoaking of RCA in 2 wt% NS solution of 24 hr, respectively. Results show that the measured 28‐day compressive strength of recycled aggregate concrete containing presoaked RCA is higher than that containing direct mixing of NS in concrete. The volume of permeable voids, water sorptivity, and chloride ion penetration measured after 28 days curing is also reduced in recycled aggregate concrete containing presoaked RCA in NS solution than that containing direct mixing of NS in concrete. The total porosity of mortar adjacent to presoaked RCA is also found to be significantly lower than the same, where NS is mixed directly. The concentration of pores in the matrix adjacent to presoaked RCA is also shifted to medium capillary pores from the large capillary pores of matrix adjacent to RCA containing no NS. The volume of medium capillary pores reduced significantly in the matrix adjacent to presoaked RCA compared to the same, where NS is mixed directly. The scanning electron microscopic image analysis also supports this observation.

Effect of water and nano-silica solution on the early stages cement hydration

The nanoscopic young’s modulus of cement paste during early ages of hydration in water and nano-silica was investigated by the application of atomic force microscopy (AFM). Peak-Force Quantitative Nano-Mechanical (PFQNM) imaging mode in atomic force microscopy was used to determine elastic modulus of cement paste before and after immersion in water and nano-silica solution. The results clearly show how mechanical and physical properties of cement grains changes progressively to higher values during the hydration process in water and nano-silica.Moreover, an empirical theory on mechanism of hydration development is proposed in the current study based on experimental observations. Average Young’s modulus of condensed cement powder was changed from about 15GPa, for unhydrated state, to 11.3GPa after two hours of hydration in water environment. The average roughness trend was also altered from 8.31nm to 18.2nm during hydration process. Results show that the cement hydration rate in nano-silica solution is much higher than water environment. Moreover transition zone between C-S-H colonies have much higher mechanical properties than the hardest colonies in every ages. In the presence of nano-silica, transition zone has a width of less than 10nm and a surface area of 5% of the overall surface area.

The effect of fluorosurfactant-modified nano-silica on the gas-wetting alteration of sandstone in a CH4-liquid-core system

In gas condensate reservoir, liquid condensation near the wellbore region might kill gas well deliverability, research shows that gas-wetting alteration can be one of effective methods to alleviate liquid condensation in porous media. However, the wettability of cores can only be altered from liquid-wetting to intermediate gas-wetting, making the improvement for gas well deliverability very limited. To achieve super gas-wetting alteration, nano-silica was modified functionally by the fluorosurfactant FG40. To evaluate the influence of gas-wetting alteration on cores, the contact angle measurement, Owens two-liquid method, capillary rise, and imbibition spontaneous tests in the CH4-liquid-core system were conducted, respectively. The results showed that the wettability of the core can be altered to intermediate gas-wetting or super gas-wetting after treatment by the FG40, FP-2, and FG40 modified nano-silica. The contact angles of the brine and decane on the core surface increased from 23° and 0° to 152° and 127°, respectively, after the 0.5% FG40 modified nano-silica treatment; these angles are obviously higher than in those cores treated with FG40 and FP-2 solutions at an equivalent concentration. Meanwhile, the surface free energy of the cores sharply decreased from about 70mN/m to approximately 0.61mN/m after the FG40 modified nano-silica treatment. The results of the capillary rise and imbibition tests were also consist with that of the contact angle measurement; the liquid levels of brine and decane significantly decreased from 27 and 13.5mm to −20 and −7mm, respectively, after treatment by the FG40 modified nano-silica solution. The imbibition of brine and oil in the core also decreased sharply due to the super gas-wetting alteration. Results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that the botryoidal structure of gas-wetting particles plays a vital role in gas-wetting alteration, which can alter the wettability of the core from strong liquid-wetting to super gas-wetting.