Silica Extraction Research Articles

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.

Stepwise extraction and utilization of silica and alumina from coal fly ash by mild hydrothermal process

Coal fly ash (CFA) is a potential secondary resource. In this study, silica and alumina from CFA were leached and utilized through a gentle alkali hydrothermal process. The results of CFA desilication with a single NaOH solution showed that amorphous silica was dissolved at a relatively low temperatures. Under optimized conditions, the leaching rate of SiO2 reached 33.81 %, while that of Al2O3 only was 1.37 %. Amorphous honeycomb calcium silicate hydrate was then well prepared by using silicon-rich liquid with CaO. The new aluminosilicate structures (sodalite) were detected in desilicated coal fly ash (DSCFA), which hinder the silica dissolution. After the optimal hydrothermal leaching in Ca(OH)2+NaOH system, the leaching rate of Al2O3 in DSCFA reached 39.84 %. The dealuminated CFA were mainly composed of friendly nano-flake tobermorite. With the increase of temperature, time, alkali concentration and Ca/Si, the tobermorite phase gradually changed to hibschite. The obtained alumina lixivium was well transformed into valuable porous boehmite via a carbonation process. Finally, the pilot tests excellent results, leaching about 41 % of SiO2 and 42 % of Al2O3, further demonstrating the feasibility of the whole hydrothermal process of desilication with a single alkali followed by aluminum extraction with mixed alkali.

Extraction of silica from natural deposits for the production of silicon in photovoltaic applications

The Silica, primarily sourced from silicon dioxide (SiO2) is a common chemical compound abundant in nature, existing in various forms such as quartz, sand, glass, and diverse minerals. It finds extensive use across multiple industries, contributing significantly to glassmaking, ceramics, abrasives, refractory materials, and serving as a crucial component in semiconductor production for electronic chips. This work provides a comprehensive review of the silica elaboration process aimed at obtaining silicon. The initial stage involves the preparation of raw materials, utilizing Algerian sand and diatomite, which undergo meticulous chemical treatment to eliminate unwanted impurities. This method comprises distinct steps, known as the purification process, wherein the sand or diatomite shell is assessed through dissolution in a caustic alkaline solution. This approach indicates the potential to generate high-quality silica from diatomite using an aqueous chemical process. This paper explores the prospect of sand or diatomaceous earth as a novel source of premium-grade silica. It discusses the effects of hydrochloric acid as a solvent for purification. This study contrasts treatment methods before and after acid leaching, focusing on samples with larger particle sizes (ranging from 53 to 300 microns), shorter refining durations (1 to 6 hours), and relatively higher temperatures (30 °C to 70 °C). The findings reveal that the highest purity of silica was attained through HCl treatment (25%).

Extraction of Silica from Natural Deposits for the Production of Silicon in Photovoltaic Applications

The growing demand for renewable energy sources has driven extensive research and development in photovoltaic technologies. Silicon, in the form of single-crystalline or multi-crystalline wafers, dominates the photovoltaic industry due to its well-established fabrication processes and desirable electrical characteristics Silicon (Si) has long been recognized as the primary material in photovoltaic devices due to its excellent electrical properties and abundance. In this work, we provide a comprehensive review of the elaboration process of silicon for photovoltaic applications. We discuss the various techniques used to produce high-quality silicon, the main steps of the silicon elaboration process can be summarized as: Raw material preparation: Quartz sand, primarily composed of Silicon dioxide (SiO2), undergoes thorough treatment to eliminate undesired impurities. It is subjected to processes such as washing, crushing, and purification to obtain high-quality raw material. Silica reduction: The SiO2 raw material is then subjected to a high-temperature chemical reaction to reduce it into metallurgical silicon (Si). Various methods, including carbothermic reduction, are employed for this process. In carbothermic reduction, carbon, typically in the form of coke, acts as a reducing agent to react with the silica and produce pure silicon. Also the purification methods, and crystal growth techniques. Furthermore, we highlight the importance of silicon's material properties and their impact on photovoltaic device performance. The aim of work is to provide a deeper understanding of the elaboration of silicon we explore our chemical methods used to produce high-quality silicon, including the purification techniques and silicon precursor synthesis and its crucial role in the development of efficient and sustainable photovoltaic technologies.

Silica extraction from bamboo leaves using alkaline extraction method

The silica is most common constituent of bamboo leaves mainly varies from 75.90 to 82.86 %.In this study, silica was extracted from bamboo leaves using an alkaline extractionprocess. In proximate analysis, bamboo leaves were found to contain significantly more ash (24.5 %) containing 79.28 % silica and low levels of fixed carbon. However, in ultimate analysis, bamboo leaves were found to contain 57.56 % oxygen.The yield and quality of silica were improved by extracting silica from bamboo leaves ash under various operating conditions.A higher concentration of NaOH (2.5 N) resulted in a greater yield of silica (97.73 %).During the alkaline process, an acid leaching treatment was used toremove metal impurities either from bamboo leaves ash or extracted silica. The silica yield increased from 97.73 % to 98.86 % after acid leaching of feed. In an FTIR analysis, Si-O-Si, Si-O, and Si-OH bonds were identified. Modern characterization techniques such as XRF were used to determine the purity of silica. There is a significant difference between the maximum purity of acid leached silica samples (96.13 %) and that of commercial silica samples (95.52 %).As a result of this study, silica that has a wide range of applications in the food and nutrition industries, the pharmaceutical industry, and as a nano-catalyst could be produced.

Detection of Tilapia lake virus (TiLV) using semi-nested RT-PCR method in farmed Tilapia (Oreochromis niloticus) from ponds East Java, Indonesia

Tilapia lake virus disease is an emerging viral disease causing mortality up to 90% worldwide of aquaculture production. It has been recorded as a virus attacting wild and cultured tilapias in Asia, Africa, and Latin America. There is the urgent need for rapid Diagnostic techniques for viral diseases to identify infected tilapia to control the outspread in individual farms. This study aims to identify the presence of TiLV with the semi-nested Reverse Transcriptase-Polymerase Chain Reaction method allowing the rapid detection of TiLV in fish organs. A total of 4 samples of tilapia were isolated from different locations and then used a silica extraction kit to obtain RNA from the TiLV virus. Afterwards amplification step was carried out by semi-nested RT-PCR test. The primers used in PCR target the 250-bp fragment in the electrophoresis. The results showed that the 250 bp amplicon of TiLV RNA was detected at 1/4 tested Tilapia. PCR clearly identified infective TiLV viral RNA in tilapia that produced a cytopathic effect with protein similarity (weak homology) in the conserved Polymerase Sub Unit PB1 Influenza-C and the genome of Orthomyxoviruses causing brain, nervous system and liver damage in fish and may have applications as rapid species-specific virulence test.

Modification of The Synthesis of Silica from Litter Ori Bambusa (Bambusa blumeana) Leaves Using Sodium and Potassium With The Hydrothermal Sol-Gel Method As Agricultural Fertilizer

Bamboo plants in Indonesia are familiar plants and have not been utilized optimally. Most people only use the stems for daily needs and a small part for industry, while the leaves are left as waste. Bamboo leaves have a fairly high silica content. Bamboo leaves that have fallen and are scattered on the ground (bamboo leaf litter) are a potential source of natural silica. Silica fertilizer in agriculture is still very necessary, especially in nanosized. Through silica extraction from bamboo leaf litter, it is hoped that it will be able to meet agricultural silica needs and reduce bamboo leaf waste. The aim of this research is to modify the synthesis of silica from ori bamboo leaf litter (Bambusa blumeana) by extracting NaOH and KOH using the hydrothermal sol-gel method to produce nano silica. Nano silica production uses the hydrothermal method because it does not require large costs, is more effective, and has a high level of purity. Synthesis of original bamboo leaf litter silica using the hydrothermal sol-gel method. Bamboo leaf litter ash was analyzed using the XRF test, and silica was analyzed using the SEM-EDX mapping test to determine its morphology and content. The research results showed that synthesis with sodium produced higher levels of bamboo leaf silica compared to potassium. The size of the silica particles obtained is still in the form of micrometers (47–52 µm). Bamboo plants in Indonesia are familiar plants and have not been utilized optimally. Most people only use the stems for daily needs and a small part for industry, while the leaves are left as waste. Bamboo leaves have a fairly high silica content. Bamboo leaves that have fallen and are scattered on the ground (bamboo leaf litter) are a potential source of natural silica. Silica fertilizer in agriculture is still very necessary, especially in nanosized. Through silica extraction from bamboo leaf litter, it is hoped that it will be able to meet agricultural silica needs and reduce bamboo leaf waste. The aim of this research is to modify the synthesis of silica from ori bamboo leaf litter (Bambusa blumeana) by extracting NaOH and KOH using the hydrothermal sol-gel method to produce nano silica. Nano silica production uses the hydrothermal method because it does not require large costs, is more effective, and has a high level of purity. Synthesis of original bamboo leaf litter silica using the hydrothermal sol-gel method. Bamboo leaf litter ash was analyzed using the XRF test, and silica was analyzed using the SEM-EDX mapping test to determine its morphology and content. The research results showed that synthesis with sodium produced higher levels of bamboo leaf silica compared to potassium. The size of the silica particles obtained is still in the form of micrometers (47–52 µm).

Comprehensive Extraction of Silica and Alumina from Coal Fly Ash via Reduced and Oxidized Roasting-Low Temperature Alkaline Leaching and Bayer Digestion

Comprehensive Extraction of Silica and Alumina from Coal Fly Ash via Reduced and Oxidized Roasting-Low Temperature Alkaline Leaching and Bayer Digestion

Optimization of purity and yield of amorphous bio‐silica nanoparticles synthesized from bamboo leaves

AbstractThe fallen yellowish bamboo leaves around bamboo crops are always overlooked even though they contain high silica in their ash. Bamboo leaf valorization consequently has the potential to be a green process for synthesizing amorphous silica. Unfortunately, the optimum process parameters have not been widely disclosed. Hence, this study intends to optimize the synthesis of amorphous bio‐silica nanoparticles from bamboo leaves using Box–Behnken design (BBD). Bamboo leaves were initially washed with HCl, followed by combustion at 700°C, and then ash washing, extraction of silica with NaOH (sol–gel method), gelation, and drying. According to the results, optimum conditions occur under no acid washing of leaves, solvent‐to‐feed ratio = 5 mL/g, and extraction duration = 1.5 h. The optimum conditions give the highest purity (94.1 wt.%) and yield (42.33%) as well as the highest surface area (328.61 m2/g), smallest pore diameter (8.69 nm), and largest pore volume (0.71 cc/g) of bio‐silica nanoparticles. Furthermore, bio‐silica nanoparticles are amorphous, spherical‐shaped aggregates, and have a white powdered colour.

Synthesis and characterization of silica xerogel and aerogel from rice husk ash and pulverized beach sand via sol-gel route

The high cost and toxicity associated with the use of orthosilicates as silica precursors drive growing interest in an environmentally friendly and cost - efficient natural silica source. Rice husk (a biomass) and beach sand are both natural and non - toxic and the extraction of silica from each using sodium hydroxide makes the process green for the production of nanosilica gels (xerogel and aerogel) via the sol – gel route. The gels from the ash of rice husk and pulverized beach sand were dried by the use of a laboratory oven and supercritical extraction methods. The structures of the gels were studied through X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), scanning electron microscopy (SEM), X - ray fluorescence (XRF) spectroscopy and Fourier transform infrared (FTIR) spectroscopic analyses. XRF spectroscopy revealed silicon in its oxide form as the prominent element with low levels of trace elements concentrations. XRD results showed the crystalline nature of the prepared silica. TEM images confirmed the crystalline and nanometric structures of the streak - free xerogel and aerogel. SAED confirmed that the gels were polycrystalline with no streaks. SEM monographs showed varied globes of fine surfaces indicating the high level of purity of the gels. FTIR showed the absorption peaks of the silanol-OH bond and Si-O-Si vibration, confirming the gels as nanometric structures. The high yield, crystalline nature, purity and crystallographic features of the produced silica suggest rice husk ash and pulverized beach sand as alternative silica sources for the production of silica gels nanoparticles with potential applications in biomedical field, nanofiltration and as additive for improving the strength of materials.

Quantification of silicon concentration in sugarcane ash using the neutron activation technique with an isotopic source

In the realm of agronomic research, the neutron activation technique has gained traction, particularly in regions such as Paraguay, for its capability to deploy an isotopic source for the quantification and identification of agriculturally pertinent minerals. Within the ambit of sugarcane cultivation, both silicon (Si) and silica (SiO2) emerge as paramount, owing to their efficacy in fortifying the sugarcane plant's resistance to phytopathogens and pests, as well as their role in mitigating lodging phenomena. Notably, an uptick in silica accumulation has been correlated with amplified biomass and sucrose production metrics. This underscores the imperative for a meticulous quantification of Si and SiO2 within sugarcane derivatives, catering to both agronomic and industrial directives. Addressing the extant lacuna in regional datasets, this investigation endeavored to elucidate the inherent concentrations of Si and SiO2 within distinct anatomical segments of sugarcane, viz., leaves, entire stems, bark, and bagasse. A total of eight sugarcane cohorts, each encompassing 10 specimens, were subjected to the experimental paradigm. Adhering to a fully randomized design, each cohort was trialed in triplicate. Post desiccation at 105°C, the resultant specimens underwent calcination in a muffle furnace at an approximation of 500°C for a sextet of hours. The experimental variables under scrutiny encompassed mass (in grams), Si concentration (in percentage), and SiO2 content. Subsequent quantifications of Si and SiO2 within the ash specimens were operationalized using a nuclear analytical modality coupled with an isotopic neutron source. Post-acquisition, the data were subjected to a unidirectional analysis of variance, with an ensuing post-hoc DMS comparative analysis. Empirical findings highlighted that ash derived from integral sugarcane stems registered a preeminent mass juxtaposed against other segments. Intriguingly, leaf-derived ash manifested the zenith of Si and SiO2 concentrations, quantified at 24% for Si and 51.5% for SiO2. In summation, the neutron activation technique, undergirded by an isotopic source, has manifested its robustness in pinpointing Si concentrations within sugarcane ash, thereby accentuating the potential of leaf ash as a quintessential fount for silica extraction. Such insights bear salient implications for nations, such as Paraguay, where the evolution of agronomic modalities remains an ongoing endeavor.

Low-Concentration Acid Treatment of Sugarcane Bagasse with Silica Extraction for Partial Cement Replacement

Low-Concentration Acid Treatment of Sugarcane Bagasse with Silica Extraction for Partial Cement Replacement

Extraction of Silica from Bamboo Leaves Ash (Bambusoideae) Using Hydrochloric Acid and Nitric Acid

Bamboo leaves, a readily available agricultural waste globally, serve as a valuable source of organic silica, often referred to as biosilica. Despite containing a substantial silicon dioxide (SiO2) content, bamboo leaves are frequently discarded by communities. Remarkably, the silica content in bamboo leaves exceeds 70%. Acid leaching is employed to extract the silica, with various factors and types of acids being compared in the process. The resulting silica is highly porous and firmly bonded. The extracted silica's purity, amorphous nature, and the presence of functional groups have been verified through XRD and FTIR studies. Additionally, TGA is utilized to monitor the material's weight changes with increasing temperature.

Extraction of Silica from Different Solid Wastes and Its Application as Catalyst Support for Vapour Phase Oxidation of Aromatic Hydrocarbon

In present study, the research work has been divided into two sections viz. Firstly, amorphous silica was extracted from different silica rich agricultural and industrial waste materials (fly ash, perlite and rice husk ash) via sol-gel method. The extracted silica (RHA-Si, Perlite-Si, FA-Si) was characterized using BET surface area, FESEM, EDS, XRD, NMR and FTIR techniques. The surface area and particle size of extracted silica was found to be 23.06-255.5 m2/g and 61-267 nm. Secondly, fly ash silica was used as catalyst support and modified desirably by loading different molybdenum weight percentages via acid impregnation method. The presence of MoO3 on the surface of extracted silica were confirmed by different characterization techniques. The kinetic studies of the FASi/Mo-15 catalyst for the vapour phase oxidation of benzene was also investigated by employing the Mars Van Krevelen model to analyze the reaction mechanism and rate of the process. The vapour phase oxidation reaction follows zero order kinetics, with faster benzene conversion occurring at lower intake concentrations and higher reaction temperatures.

Pilot-scale continuous biogenic silica extraction from rice husk by one-pot alkali hydrothermal treatment and ball milling

BackgroundRice husk is the most silicon-rich renewable biomass and can be used as a raw material for producing silicon-based materials. With the increasing interest in utilizing rice husk as a renewable resource, the development of a robust silica extraction method is required. In this study, a one-pot alkali hydrothermal and ball-milling continuous silica extraction method was developed at the pilot scale.ResultsThree residence times (50, 100, and 150 min) were selected to compare the performance of the continuous extraction process depending on the residence time. The silica production was 4.09, 2.67, and 2.22 kg day−1 while the silica extraction yield was 52.8, 69.1, and 86.0% at resident times of 50, 100, and 150 min, respectively. The energy consumption for producing 1 kg of silica from rice husk was 51.6, 47.7, and 47.4 MJ kg−1 at resident times of 50, 100, and 150 min, respectively. The one-pot continuous silica extraction process was performed for 150 h to verify the stability of the process. During long-term operation, the process exhibited a constant solid content and stable silica extraction yield. The silicate solution obtained by the one-pot continuous process was successfully used to synthesize size-controlled spherical silica particles, which had a purity of 99.1 wt% and amorphous structure.ConclusionsOverall, this study presents a novel continuous silica extraction method for the efficient recovery of silica from rice husk-based biorefineries.Graphical abstract

Applicability of Rice Husk Residue Generated by the Silica Extraction Process to Anaerobic Digestion for Methane Production

Rice husks are a feedstock of biogenic silica because of their high silica content. After silica extraction, a solid residue comprising mostly carbohydrates is present. Solid residue valorization is important for closed-loop systems using rice husk and has minimal negative environmental impacts. In this study, we used solid rice husk that was generated by silica extractionto anaerobic digestion for producing biomethane. The rice husk residue was characterized in terms of total solids, volatile solids, pH, composition, and particle size. Changing the characteristics increased biogas production by 2.48-fold compared to that of raw rice husk. The residue produced 166.4 mL-biogas g−1 vs. and 100.4 mL CH 4 g−1 VS, much more than previously reported. Microbial community analysis, which was conducted to investigate the biological reasons for increased biogas and methane, found increased Bacteroidetes levels in the rice husk samples. Among archaeal communities, Bathyarchaeota was more abundant in all rice husk samples than in the inoculum. The rice husk residue contained more operational taxonomic units than other samples. These changes in the microbial community significantly influenced the anaerobic digestion of the rice husk residue and improved methane production. Our findings provide a basis for the cleaner utilization of rice husk residue to produce renewable energy.

Deep Processing of Dump Slag from the Copper-Nickel Industry

This work proposes an environmentally safe and economically feasible method of waste copper-nickel production slag utilization (Kola Mining-Metallurgical Company, Nornickel, Kola Peninsula, Russia). This process involves the decomposition of slag by diluted solutions of sulfuric acid (7–10 wt.% H2SO4) with a transfer in a solution of more than 70% silicon, 77% iron and 78% magnesium, and a concentration of non-ferrous metals in the residue (~70%). Copper ions were used in the leaching stage to prevent the release of hydrogen sulfide into the working atmosphere. Dehydration of the solution, followed by washing of water-soluble sulphates from silica, was carried out to separate silica from the leaching solution. The dehydration temperature effect on the silica structural characteristics was determined. The possibility of recovering non-ferrous metals from solutions after silica extraction by precipitation, in the form of copper cementite, and the sum of nickel and cobalt sulfides, was evaluated. Pigment-grade iron dioxide, magnesium sulphate and aluminium hydroxide were obtained by dehydration of the solution after extraction of base metals, calcination and other operations. Sulfuric acid leaching resulted in the disclosure of sulfide grains encapsulated in ferrosilicate, which is a favorable factor for flotation. The depleted residue can be successfully used in the construction industry.

Nanosilica Extraction from Grumusol Soil

Grumusol soil is a type of soil that contains significant amounts of silica. Silica content in grumusol soil can reach up to 90%. The aim of this research was to determine the characteristics of silica nanostructures in Grumusol soil. The stages of the research were carried out including the preparation of raw materials, silica extraction, and XRD analysis. The raw material preparation stage is carried out by cleaning the grumusol soil from dirt. The second stage was carried out by synthesizing silica with the base extraction method and followed by acid deposition. The final stage is X-Ray Diffracion (XRD) analysis. The results of the research that has been carried out is the FWHM value of 0.0900 (<0.1) which indicates that the crystals produced have very good crystals with a very regular structure. The crystal size which includes nanosilica is 39.5076-48.6633 nm for 3M NaOH with 1 and 3 hours extraction time and 5M NaOH with 1 hour extraction time

Aluminum-based activation of natural zeolite for glycerol steam reforming

In this work, aluminum-based activated zeolite is employed for the first time in glycerol steam reforming. AlCl3 and Al(OH)3 were used as the activator agents for the natural zeolite. NiMo/Zeolite catalysts were prepared for the glycerol steam reforming process by impregnation and characterized by XRD and XRF. The characterization results showed that the activation by AlCl3 and Al(OH)3 could modify the chemical composition and crystallinity of the zeolite. Silica extraction occurred due to the activation by Al(OH)3, while AlCl3 caused an aluminum removal in the zeolite framework. Amorphization of zeolite structure was involved in zeolite activation by Al(OH)3. Glycerol steam reforming processes employed NiMo/Zeolite-AlCl3 and NiMo/Zeolite-Al(OH)3, which were carried out in a fixed-bed reactor at 250 °C. The glycerol-water mole ratio was varied 9:1, 4:1 and 3:2. NiMo/Zeolite-AlCl3 yielded a higher hydrogen product than NiMo/Zeolite-Al(OH)3 with a lower glycerol feed concentration.