Amount Of Silica Research Articles

Process Optimization and Mechanism Study for Sulfur Recovery from High-Silica Phosphogypsum via Carbothermal Reduction Smelting.

Phosphogypsum produced from wet-processed phosphoric acid mainly consists of calcium sulfate dihydrate, which is an important sulfur resource. The traditional sulfuric acid and cement process based on phosphogypsum suffers from unstable cement quality owing to impurities such as phosphorus and fluorine and kiln ringing caused by the low-melting phase. This study investigated sulfur recovery and value-added utilization of liquid slag from high-silica phosphogypsum via carbothermal reduction smelting. A phosphogypsum ingredient (PGI) system was constructed by adding appropriate amounts of silica, alumina, magnesium oxides, and iron oxides to meet the production requirements of slag wool. Carbothermal reduction smelting experiments suggested that the temperature and C/S molar ratio significantly affected the desulfurization rate and phase structure of the slag. More than 97.44 wt % of sulfur could be recovered with a C/S molar ratio of 0.5-0.8 at 1300 °C or above in the molten state, and the molten slag was an amorphous magnesium-calcium-aluminosilicate. The PGI desulfurization mechanism is discussed based on the phase transformation and slag microstructure evolution.

A Review on the Extraction of Silica Nanoparticles from Poaceae Family via Sol-Gel

One of the valuable inorganic multifunctional chemical substances is silica, which can be found in crystalline, gel, and amorphous forms. On the crust of the earth, silica is the most complex and abundant family of materials, and it has been used extensively in ceramics, adhesives, detergents, dental materials, electronics, pharmaceutical items, and chromatography column packing. Several kinds of research have fascinated the recycling of agricultural wastes using extraction for useful products such as silica, lignin, adsorbents, cellulose, biofuels, silicon, carbon, and inhibitors. In this review article, we report most of the silica nanoparticles extracted from the Poaceae family since they accumulate significant amounts of silica, and most of them are easily found in Malaysia. This study investigates the significant amount of extracting silica nanoparticles from the Poaceae family via green technology sol-gel technique as pure silica can be produced with the potential to manage the size of the particle, size of distribution, and morphology via the reaction parameters in systematic monitoring. This technique can also produce pure silica using a low-energy method. Subsequently, the key chemical compounds that existed in silica nanoparticles are characterized and identified using FTIR analysis. According to this article, most of the Poaceae family species are considered to gain a high purity of above 90% of silica based on the quantification results. The Poaceae family is recognized for having high silicon concentrations. However, the concentration varies depending on the species.

Synthesis of Zn/SBA-15 from Rice Husk Ash Using Sonochemical Methods as a Quercetin Drug Delivery Matrix

Quercetin is a drug candidate with bioavailability but currently limited, necessitating the use of a delivery matrix, such as Santa Barbara Amorphous-15 (SBA-15). Rice husk ash, containing a significant amount of silica, served as a precursor in the synthesis of SBA-15, which can be functionalized with nanoparticles, including zinc, using sonochemical methods. Therefore, this study aimed to synthesize Zn/SBA-15 using sonochemistry and evaluate the potential as a drug delivery matrix for quercetin. SBA-15 was formed by sonication of a sodium silicate from rice husk and pore director Pluronic P-123, followed by impregnating Zn at 2%, 4%, and 6% w/w. The characterization of X-ray diffraction (XRD) and fluorescence (XRF) showed a broad peak at 2theta 18-30◦ with Zn levels of 1.89%, 3.69%, and 5.06%. Furthermore, the analysis of transmission electron microscopy (TEM) showed the presence of Zn nanoparticles with a range size of 4-14 nm. In vitro drug delivery experiments were carried out using Zn/SBA-15 at concentrations of 1:1 and 1:2 to quercetin. The in vitro test results for a drug loading of quercetin with Zn/SBA-15 6% 1:1 was 28.30 mg/g. The encapsulation efficiency was 10.96% and the drug release reached 33.64% after 240 minutes.

Resistance of eogenetic dolomites to geochemical resetting during diagenetic alteration: A case study of the lower Qiulitage Formation of the Late Cambrian, Tarim Basin

Rare earth elements (REEs), carbon, oxygen and Mg isotopes have been widely used to explain the origin of dolomite, but dolomite may undergo complex diagenetic alteration during long geological processes, and whether the geochemical signals of precursor dolomite can be preserved is still unknown. In order to further explore the formation mechanism of dolomite and the influence of diagenetic alteration processes on geochemical parameters, this paper takes the thick-layer dolomite of the Lower Qiulitage Formation of the Late Cambrian in the Tazhong uplift area as an example and divides the dolomite into two categories through petrologic observation. One category is fabric-retentive dolomite (FRD), including algal clotted dolomite, algal psammitic or psammitic grain dolomite, and aphanocrystalline dolomite; the other category is fabric-destructive dolomite (FDD), including crystalline dolomite (CD) and siliceous dolomite (SD). Cation ordering, unit cell parameters, major/trace elements, REEs as well as C–O–Mg isotopes of the pure matrix powders of different types of dolomites are further analyzed. The results show that the dolomites are near-source/far-source seepage reflux type and sabkha type eogenetic origin, and the magnesium ions mainly come from Late Cambrian seawater; dolomite crystals of different sizes are the result of the precursor dolomite suffering varying degrees of recrystallization during the early diagenesis period, inheriting the original geochemical characteristics; hydrothermal alteration occurs in the late stage of diagenesis, with limited magnesium ions in the hydrothermal fluid. Its impact on the dolomite is mainly reflected in local dolomite distortion and a large amount of aphanocrystalline silica and coarse-grained quartz cement filling, which fails to obviously reset the geochemical information of the matrix dolomite. The above results demonstrate that, under favorable conditions, early genetic marine dolomites may resist geochemical resetting over time intervals of more than 400 million years.

MICROSTRUCTURE OF CB/SIO2 HYBRID REINFORCED SOLID TYRE TREAD COMPOUND CONTAINING GROUND TYRE RUBBER AND THEIR EFFECT ON FATIGUE RESISTANCE

The possibility of improving the properties of rubber compounds containing ground tyre rubber (GTR) is an active research area. This study investigates the microstructure of carbon black filled tyre tread compound containing 20 phr GTR and compares the microstructure with those of similar compounds reinforced with hybrid carbon black/precipitated silica (CB/SiO2). In the compounds reinforced with hybrid filler, amount of the GTR was maintained at 20 phr, while the amount of the hybrid filler (CB/SiO2 ) were in the ratios 55/5, 50/10 and 45/15 respectively. The compounds were mixed by two-step mixing method using internal mixer and two-roll mill. The vulcanisation of each rubber compound was carried out on a compression moulding machine at 150. Results obtained from scanning electron microscopy of the fractured surfaces showed that the ingredients in the control sample that was not filled with GTR were well dispersed and distributed. The micrograph of the sample containing GTR and mixed at 60 showed that GTR was not very compatible with the matrix. Improved mixing was achieved with increased mixing temperature. The addition of precipitated silica at 5 phr resulted in poor dispersion. The dispersion improved as the amount of silica increased to 10 phr and 15 phr respectively. Results obtained from flex fatigue test show that the compounds filled with hybrid CB/SiO2 in the ratios 50/10 and 45/15 phr exhibited no crack after 1000 cycles due to good dispersion. It is recommended that hybrid CB/SiO2 reinforcement at optimal amount of silica should be utilised to fill rubber compounds containing GTR in order to improve the properties of the vulcanisates.

Silica-Containing Phosphorus-Based Sol-Gel Finishing to Improve Flame Retardant Performance of Cotton Fabrics

In this paper, the sol-gel technique was used to design hybrid phosphorus-doped silica structures for improving the thermal stability and flame retardancy of cotton fabrics. To this aim, diethylphosphatoethyltriethoxysilane (DPTS) was employed as phosphate alkoxysilane in a multistep procedure that involved multiple layers (from 1 to 6) depositions. The multi-layer coatings were applied by padding using sols containing appropriate molar ratios of the precursor, anhydrous ethanol, catalyst, and hydrochloric acid. Moreover, the synergism P-N on flame retardancy of cotton was assessed by introducing 3-aminopropyltriethoxysilane (APTES) as an N-donor precursor in DPTS sols. The effects of the catalyst during the alkoxide reaction and the silica amount applied by sol-gel treatment on the thermo-oxidative behavior of the treated fabrics were deeply studied. The creation of the silica skeleton on the cotton surface and the interactions between the cellulosic fibres and the doped layer were investigated using FT-IR ATR spectroscopy. Moreover, thermal and thermo-oxidative stability, flammability properties, and combustion behavior of the sol-gel treated cotton fabrics were also studied, proving the effectiveness of the sol-gel coating in the fire protection of the cellulosic substrate.

Translucent superhydrophobic coating for murals protection

This study aims to protect murals by a translucent and superhydrophobic coating using a one-step spraying process, which offers simplicity, efficiency, and cost-effectiveness, while preserving the mural's visual appeal and safeguarding against moisture. Despite numerous advancements in cultural relic conservation, the application of super-hydrophobic coatings for mural preservation remains a novel approach. The coating consists of acrylic resin (Paraloid B72), nano-silica, and polydimethylsiloxane (PDMS). The optimal amounts of silica and PDMS were 3 g each in a basal solution containing 12 g of acrylic resin dissolved in 88 mL of xylene. The resulting composite coating displayed exceptional water repellency, as indicated by a contact angle of 165.5° and a rolling angle of approx. 7°. As a result, the moisture absorption of the mural decreased significantly from ∼53% to ∼5% after the application of the superhydrophobic coating. The coating had minimal impact on the water vapor permeability of the mural, with a ca. 13% decline rate. The coating is translucent with a visible transmittance of approximately 60%. Therefore, the coated mural maintains its original appearance with minimal changes. Furthermore, the superhydrophobic properties of the coating remain intact even after undergoing five cycles of high-low temperature fatigue tests, 196 hours of ultraviolet irradiation, or seven cycles of sand impacting.

Effect of interfacial sacrificial bonds on the vulcanization and mechanical properties of styrene butadiene rubber/talcum powder composites

AbstractTalcum powder (Talc) contains large amounts of silica; however, its poor surface compatibility with diene rubber makes it difficult to develop its application in styrene‐butadiene rubber (SBR). Herein, a method to enhance the compatibility of Talc with SBR via interfacial sacrificial bonds of 4‐vinylpyridine and Mg2+/Zn2+ is proposed. Poly(isoprene‐co‐4‐vinylpyridine) copolymers, designated PIPVP‐10 and PIPVP‐20, were synthesized via reversible addition‐fragmentation chain transfer polymerization. PM1‐Talc and PM2‐Talc were obtained by spraying PIPVP‐10 and PIPVP‐20 solutions onto the Talc surface, followed by drying. During thermal vulcanization, the double bonds in the copolymers can be grafted directly onto the rubber skeleton. The vulcanization rates of the SBR/PM1‐Talc and SBR/PM2‐Talc complexes were accelerated by 65% and 77%, respectively, compared with that of SBR/Talc. Simultaneously, the interfacial interaction between SBR and Talc is enhanced owing to the formation of metal–ligand bonds between pyridine and Mg2+/Zn2+. As a result, the tensile strengths of SBR/PM1‐Talc and SBR/PM2‐Talc are 5.8 and 7.9 MPa, 65% and 127% higher than that of SBR/Talc (3.5 MPa).

Identification and characterization of tephra for geopolymer precursor

Abstract Volcanic ash and pumice are products of volcanic eruptions characterized by a high amount of amorphous silica and alumina. They can potentially serve as a source of raw materials for the production of geopolymers. Geopolymers are more environmentally friendly compared to conventional cement. However, there is a requirement for aluminosilicate for creating geopolymers. This study aims to identify the mineralogical composition and chemical properties of the volcanic ashes and pumices that are potentially used as geopolymers precursor materials. Tephra and pumice samples were collected from several volcanoes in Indonesia. The samples include two tephras from recently erupted volcanoes in Java and one pumice material from West Sumatra. Tephras were collected one week after the eruptions of Mt. Tangkuban Perahu (26th July 2019). Another source of tephra was collected from Mt. Kelud, which erupted on 13th February 2014. Pumice samples of Mt. Maninjau were collected at Sungai Limau district, 30 km from the Maninjau caldera, a product of the Holocene (52K) volcanic eruption of Mt. Maninjau. Mineralogy of the tephra and pumice samples was identified with XRF and XRD. Chemical properties characterized include pH, exchangeable cations, cation exchange capacity (CEC), potential-P, and available-P. Results showed that crystalline feldspar minerals and amorphous volcanic glass dominated volcanic ash and pumice. The SiO2 content is higher in pumice, followed by tephras from Mt. Tangkuban Perahu and Mt. Kelud (74.97%-60.28%). But the Al2O3 content is higher in Mt. Kelud compared to pumice and Mt. Tangkuban Perahu (23.57%-4.03%). The pH is very acidic to slightly acidic (2.35–6.1). Mg is higher than Ca, Na, and K. The potential-P and available-P were considered very low. Among the samples, Mt. Kelud volcanic ash has the highest available P compared to Tangkuban Perahu volcanic ash and pumice. The SiO2/Al2O3 ratio are 4.35, 8.00, and 26.38 for samples of Mt. Kelud, Mt. Maninjau pumice, and Mt. Tangkuban Perahu, respectively. The optimum ratio of geopolymer is between 2.5–5; thus, volcanic ash Mt. Kelud is the most suitable option. Nevertheless, the exchangeable basic cations of volcanic ash and pumice indicated that they are more suitable for plant nutrition.

Stone mining work and dust pollution in Birbhum district, West Bengal, India.

Dust pollution is common in Indian roads and several industrial settings (including mines) that affects human health. Identification and characterization of the dust particles in the mining area is essential for knowing the properties of the dust that effectively causes ailments to humans, particularly among workers those who are working in unorganized industrial settings. The present study aimed to determine the level of dust pollution and to know the size and characterize the dust particles in the Pachami-Hatgacha stone mine areas of Birbhum district, West Bengal, India. Dust samples were collected and analysed for Dynamic Light Scattering (DLS) to determine the size and shape of the particles, Fourier Transform Infrared Spectroscopy (FT-IR) to determine the free silica content, and X-ray Florence (XRF) analysis for quantitative estimation of components in the sample. All the analyses were done following standard instrumentation and techniques. The size of the dust particles was much less (ranges 101-298nm) than the size of respirable particles (2500nm). Those were mostly generated as well as precipitated during peak working hours of the day. Presence of considerable amounts of silica was confirmed by the FT-IR (strong and broad band at 1000cm-1) and XRF analysis (76.85% SiO2). Exposure to these dust particles may cause severe health impairments. Therefore, interventions like wet drilling and blasting, sprinkling of water during peak working hours, and awareness of use of personal protective devices among workers are required to reduce the risk and hazards associated with dust pollution to the health of miners and inhabitants around the mines.

Did Algae Eat All the Silica in the World’s Oceans?

Silicon is a crucial nutrient that can join with the element oxygen to form a substance commonly called silica. Silica, commonly known as glass, is found in rocks in the Earth’s crust and dissolves into the oceans, where organisms like algae and sponges use it to build their glassy skeletons. This process, called biosilicification, is extremely important in the silica cycle. Over time, organisms have changed the silica cycle. Today, because of these organisms, the oceans no longer contain much silica. However, when the Earth was younger and these organisms had not evolved yet, no biological processes affected silica in the oceans. The evolution of these oceanic organisms across time has removed silica from the oceans. In this article, we discuss how the evolution of silicon-using sponges, as well as tiny organisms called zooplankton and algae, have changed the amount of silica in the world’s oceans through geologic time.

Eco-Friendly Methods of Silica Extraction from Pyrophyllite Rocks Using Sol-Gel versus Alkali Fusion Method

Silica is the most abundant compound on the Earth’s surface. The content of silica can be found in agricultural waste ash and mineral rocks. Extracting silica from natural sources is advantageous due to its economic feasibility and easily obtained. Silica has a wide range of applications, such as in fertilizers, adsorbents, organic reaction catalysis, biofuels/alternative energy production, and as an antimicrobial agent. One type of rock that contains the highest amount of silica is Pyrophyllite. Recent research trends have focused on various methods and sources for silica extraction, yet extracting silica from mineral rocks presents its own challenges. Pyrophyllite rock contains a high amount of silica, but its extraction is quite difficult due to the presence of crystalline silicate mineral phases. This study aims to compare the silica extraction process on Pyrophyllite rocks from Malang using the sol-gel method versus the alkali fusion method.

Extraction of silica from sugarcane bagasse ash and its utilization in zeolite 4A synthesis for CO2 adsorption.

Sugarcane bagasse ash (SCBA) is a solid waste containing a high amount of silica (SiO2) and is suitable to utilize as a silica source for synthesizing zeolite NaA. SCBA is typically calcined at high temperatures before silica extraction. The method is not environmentally friendly because it consumes energy and produces CO2. This work demonstrates an alternative extraction method of SiO2 from SCBA by treating it with hydrochloric (HCl) and sodium hydroxide (NaOH) solution. The obtained mixture was separated by paper filter No. 1 (P) and a combination of paper filter and syringe filter (PS). The solution was neutralized by HCl solution, producing silica (SiO2-P and SiO2-PS) with a purity of 98 wt%. Both SiO2 samples and SCBA were utilized to synthesize zeolite NaA for CO2 adsorption. The CO2 adsorption capacities of NaA-P and NaA-PS were 4.30 and 4.10 mmol gadsorbent -1, in the same range as commercial NaA. The capacity is influenced by the total basicity of zeolite. The CO2 adsorption behavior of all samples correlates well with the Toth model. The CO2 adsorption kinetics agrees well with the pseudo-second-order kinetic model. Overall, this work shows the successful extraction of silica via using a direct NaOH solution, yielding high-purity silica sufficient for synthesizing zeolite NaA, a promising adsorbent of CO2.

Epoxy–Silica Functionally Graded Materials: A Review

This article provides an overview of the studies that have been conducted on the characteristics of epoxy resins containing various types of silica nanoparticles and microparticles, as well as their performance in the industrial application of functionally graded materials (FGMs). Silica nanoparticles and microparticles are used to create epoxy resins in order to improve various properties, such as thermal stability, adhesiveness, electrical conductivity, strength, modulus, and toughness. This review examines the literature that has been published in the last decade, compares the results, focuses on the mechanical and thermal properties, and discusses the changes that have resulted in improvements in those properties. Previous experimental findings are presented and contrasted to demonstrate the extent to which silica filler content contributes to improving the properties of composite materials. The findings reveal that the characteristics of epoxy compounds can be improved by adding a particular amount of silica particles. There is a correlation between an increase in the silica amount and an increase in the Young modulus of epoxy compounds, this correlation becomes stronger as the silica amount increases. Additionally, the tensile strength of epoxy compounds increases to a certain limit as the amount of silica nanoparticles increases. In contrast, the hardness of the material increases as the silica amount increases. The density of the material also increases steadily as the silica amount in the material increases. According to thermal analysis results from calorimetric research on epoxy–silica systems, the glass transition temperature increases as the silica amount increases.

Synergistic effects of supplementary cementitious materials and compressive strength prediction of concrete using machine learning algorithms with SHAP and PDP analyses

In order to reduce the CO2 associated with cement production, this study explored the potential of rice husk ash (RHA) and fly ash (FA) as supplementary cementitios materials for partially replacing cement in concrete production. The study aimed to analyze the synergistic effects of a cement-based mixture consisting of RHA and FA in different proportions on concrete's fresh, hardened, non-destructive and microscopic properties. In addition to the experimental work, this study successfully applied machine learning to predict the compressive strength of RHA-FA concrete using three types of algorithms: ANN (Analytical Neural Network), XGB (Extreme Gradient Boosting), and GBM (Gradient Boosting Model). A total of 138 data points were used for this prediction, and statistical and parametric analyses were performed to define the impact of input parameters on the outcome. Furthermore, both destructive and non-destructive tests were conducted on hardened concrete, including compressive strength, split tensile strength, ultrasonic pulse velocity (UPV), and rebound hammer. The scanning electron microscope (SEM) was operated to analyze the microstructural characteristics of concrete. The compressive and split-tensile strength test results showed that the mixture with a higher percentage of fly ash and a lower percentage of rice husk ash achieved maximum strength. The X-ray Fluorescence (XRF) analysis revealed that both ashes contained a significant amount of silica, which gave them excellent pozzolanic properties. After 28 days, both the UPV and the rebound hammer strength align with the destructive compressive strength results. The study also employed SHAP (SHapley Additive exPlanations) and PDP (Partial Dependence Plot) analyses to identify the optimal range for each parameter's contribution to strength improvement. The machine learning models exhibited a strong correlation with the test results, achieving an R2 value of 0.84 for the XGBoost model.

Maceral composition, coal quality and depositional environments of the middle Permian Ukhaakhudag coal deposit, South Mongolia

The Ukhaakhudag coal deposit is located c. 560 km SSE of the city of Ulaanbaatar in the northeastern sector the South Gobi Basin. The coal-bearing strata is part of the middle Permian Tavantolgoi Formation. This study aims to determine the coal petrographic composition and depositional environments of five coal seams in the lower part of the deposit based on petrographic and chemical analyses of 106 composite samples. Vitrinite ranges from 12 to 64 vol.%, and inertinite varies between 9 and 68 vol.%. Liptinite ranges from 1 to 7 vol.%. Microlithotype analyses indicate that coals are primarily vitrinertite, few coals are classified as trimaceralic microlithotypes duroclarite and clarodurite. The inorganic fraction in the studied coals is mainly composed of clay, small amounts of silica, carbonate, and pyrite minerals. The vitrinite random reflectance values of the samples vary between 0.93-1.16 %. Volatile matter content varies from 26.10 to 41.48 wt.% (dry ash free basis). Ash, moisture, and sulfur contents vary between 11.20-44.76 wt.%, 1.63-6.03 wt.% and 0.49-1.67 wt.%, (air dried basis) respectively. Based on random vitrinite reflectance values and volatile matter content, the studied coals are classified as coking (Ch4), fat (Ch5), 1/3 coking (Ch6), gas fat (Ch7) based on the Mongolian system and medium to high volatile bituminous coal when using the ASTM system. The Gelification Index and Tissue Preservation Index of the studied samples suggest most seams accumulated in wet forest swamps with a high tree density. The Middle Permian peats from this location accumulated in mostly alternate oxic and anoxic mire conditions. The climate was drier during the peat accumulation of Seam 0, but it became warmer, and humidity increased starting from Seam 3 accumulation.

Response Surface Methodology Approaches in Producing Amorphous Silica from Rice Straw Ash

A large amount of rice straw is produced as crop residue from rice production as an underutilization waste material. The open burning of rice straw can lead to environmental pollution by forming an abundant amount of rice straw ash (RSA) and exposing harmful gases to the atmosphere. Thus, RSA can be used as a cement replacement material due to its high amount of silica. Silica is a helpful additive to cement mix by accelerating the hydration process of cement because of its high reactivity and improving mortar performance. This study focuses amount of high silica of RSA in modified concrete through thermochemical pretreatment via response surface methodology (RSM). The factors involved in the pretreatment of RSA are 0.01M – 0.1M HCl hydrochloric acid, 1 – 3 hours soaking duration, and 60 - 80℃ soaking temperature, and a response is the percentage of reactive compound content (SiO2, Al2O3, and Fe2O3). Therefore, central composite design (CCD) in the RSM and the analysis of variance (ANOVA) have been used to evaluate the interaction between the factors and response, then simulated and further assess the accuracy of the model to achieve the accurate prediction. As a result, RSM observed that the optimum silica amount in the treated RSA (98.34%) was produced using parameters of 0.06 M HCl, 2 hours of soaking duration, and 70℃ soaking temperature in the pretreatment process. After that, it is followed by a burning process at a controlled temperature and a grinding process to produce treated RSA. The prediction given by the RSM was not the sole result but was proved through X-Ray Fluorescence (XRF) analysis. The result of XRF analysis obtained for each model with the same value of each factor (HCl concentration = 0.06 M, soaking duration = 2 hours, and soaking temperature = 70℃) is more than 97.00% and falls between the prediction index range. Thus, the model is validated since the actual experimental result is within the expected range for any involved factor. Hence, the treated RSA was considered a high-quality pozzolanic material incorporated in the mortar production.

A contribution to the understanding of hydrochemical properties of thermo-mineral water on the L’dži locality (eastern part of North Macedonia)

Regarding the aspect of mineral, thermo-mineral, and thermal waters, on the territory of the Republic of North Macedonia, there are 65 registered locations, of which 8 are categorized as spas. This includes the Kežovica spa, also known as the Štipska spa. In the vicinity of Kežovica Spa is the thermo-mineral L’Dži spring with mineralization around 1.3 g/L and the water temperature at the time of sampling was 50.1°C. Spring L’Dži is generated by a fault structure and is linked to a granite massif of Mesozoic age. These are alkaline waters (pH=8.3) and the hydrochemical type is chloride-sodium. Regarding the trace elements, the water of the L’Dži spring contains a large amount of boron and silica. Water also contains an increased content of arsenic (200 µg/L) and tungsten (169 µg/L). Elevated concentrations of As and W are characteristic of alkaline thermal waters in reducing conditions. Often elevated concentrations of Mo are accompanied by elevated concentrations of As and W, which is also the case.

Effects of nanosilica on the properties of brine-base drilling fluid

In the process of drilling oil and gas wells, the shrinkage and falling of wellbore walls are often caused by the expansion of mud shale water. To date, conventional additives have been unable to plug the pore throats of shale rock with nanoscale pores and thus cannot effectively solve the problem of wellbore instability encountered in shale formation drilling. In view of this situation, the idea of using nanosilica to plug the nanopore throat of mud shale is proposed to reduce its permeability and to slow water intrusion. The influences of nanosilica on the properties of brine-base drilling fluid drilling fluid are evaluated by measuring the viscosity, filtration loss and swelling of the drilling fluid. The results of laboratory experiments show that the improvement in drilling fluid properties can only be achieved on the basis of salt resistance; that is, a salt-resistant soil slurry should be used. A concentration of 1–5% nanosilica can improve the viscosity of the drilling fluid by increasing the internal friction between particles. However, nanosilica materials are sensitive to salt concentration. Nanosilica particles can be deposited on the surface of a filter cake to block the pores of the filter paper, and the filtration loss reduction rate can reach 40.2%. Blocking the pores of the clay plays a role in preventing the clay from absorbing water and expanding. The optimal addition amount of silica is 3%, and its salt resistance can reach 16%. Considering the experimental results of filtration loss, swelling amount and cost performance, 3%NP + 4%NaCl + SWM-B is selected as the optimal formula. The results of this study can be applied to effectively improve the phenomenon of wellbore instability during drilling in shale formations, and it has important application value.

Development, Characterization, and Antibacterial Analysis of the Selenium-Doped Bio-Glass-Collagen-Gelatin Composite Scaffold for Guided Bone Regeneration.

Background Guided bone regeneration (GBR) is an often-used technique to aid the successful placement of dental implants in sites with deficient bone. The search for the ideal GBR membrane with bioactive components improving the regenerative outcomes is still on. In this study, a novel composite GBR membrane was developed using selenium-doped bio-glass, collagen, and gelatin. It was further characterized for surface, chemical, biocompatibility, and antibacterial properties. Methodology Selenium-doped bio-glass was prepared using the sol-gel method. The membrane was fabricated using an equal ratio of collagen and gelatin mixed with 1% selenium-doped bio-glass. The solution was poured to obtain a thin layer of the material which was lyophilized to obtain the final GBR membrane. The membrane was analyzed with scanning electron microscopy, energy dispersive X-ray (EDX) analysis, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), zebrafish cytotoxicity test, and antibacterial assay. Results The membrane revealed good surface roughness with lamellar and fibrillar arrangement with a minute granular surface ideal for cell attachment and proliferation. The EDX analysis revealed the presence of carbon, oxygen, and nitrogen as predominant components with trace amounts of calcium, phosphorus, silica, and selenium. Fourier transform infrared spectroscopy analysis also proved the presence of collagen, gelatin, and bio-glass. The membrane revealed excellent biocompatibility with zebrafish growth at a normal rate with 90% viability maintained at 48, 72, and 96 hours and 95% viability at 120 hours. It also exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli with minimal growth of bacterial colonies. Conclusion The developed novel selenium bio-glass collagen and gelatin composite scaffold has a good surface and antibacterial properties along with excellent biocompatibility. Further cell line and in vivo studies should be conducted to explore its role in bone regeneration.