Synthesis Of Silica Research Articles

Mesoporous silica supported ionic liquid materials with high efficacy for CO2 adsorption studies

CO2 capture from industrial processes and power plants, contribute to curbing global warming and advancing sustainability efforts. This study involves the design and synthesis of novel mesoporous silica supported ionic liquid based adsorbents for carbon dioxide capture. Utilization of MSILs delves into the efficiency and mechanisms of CO2 adsorption, offering insights for sustainable carbon capture technologies in combating greenhouse gas emissions. 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethyl sulfate and 1-ethyl-3-methylimidazolium methylsulfate ionic liquids were anchored on the surface of mesoporous silica which then led to highly efficient adsorbent material. Simple, efficient and cost saving methodology was performed to synthesize such highly efficient CO2 adsorbent materials. In addition, we theoretically predicted the favorable interaction mechanism of chosen molecular entities for CO2 adsorption using density functional theory (DFT) analysis. Theoretical results depict the strong interaction of molecular entities with CO2 gas molecules which is clearly evident from the experimental findings.

Nanoengineered Silica-Based Biomaterials for Regenerative Medicine.

The paradigm of regenerative medicine is undergoing a transformative shift with the emergence of nanoengineered silica-based biomaterials. Their unique confluence of biocompatibility, precisely tunable porosity, and the ability to modulate cellular behavior at the molecular level makes them highly desirable for diverse tissue repair and regeneration applications. Advancements in nanoengineered silica synthesis and functionalization techniques have yielded a new generation of versatile biomaterials with tailored functionalities for targeted drug delivery, biomimetic scaffolds, and integration with stem cell therapy. These functionalities hold the potential to optimize therapeutic efficacy, promote enhanced regeneration, and modulate stem cell behavior for improved regenerative outcomes. Furthermore, the unique properties of silica facilitate non-invasive diagnostics and treatment monitoring through advanced biomedical imaging techniques, enabling a more holistic approach to regenerative medicine. This review comprehensively examines the utilization of nanoengineered silica biomaterials for diverse applications in regenerative medicine. By critically appraising the fabrication and design strategies that govern engineered silica biomaterials, this review underscores their groundbreaking potential to bridge the gap between the vision of regenerative medicine and clinical reality.

Synthesis and study of organo-modified silica based hydrogels: Rheological properties and drug release kinetics.

The method of synthesis of unmodified and organo-modified silica hydrogels and their composites with orotic acid as a model drug was developed. The hydrogels had a pH of 6.5-7.8. The particulate nature and highly porous structures of the hydrogel materials were revealed using scanning electron and optical microscopy methods. The content of aqueous phase in the hydrogels was 99% or more. In order to evaluate the possibility of their application as a basis for development of novel soft drug formulations and cosmetic compositions, rheological properties of the hydrogels and in vitro release kinetics of the drug were studied. The effects of synthesis conditions (increasing concentration of catalyst of silica sol formation, drug loading) and the silica matrix modification with various organic groups on the indicated properties were investigated. It was found that all synthesized hydrogels exhibited pseudoplasticity, thixotropy and controlled release of the drug, which are important for their potential application. However, in general, the indicated effects led to worsening the properties of the hydrogel materials in comparison with the unmodified silica hydrogels.

Facile room temperature synthesis of size-controlled spherical silica from silicon metal via simple sonochemical process

The waterglass or St o¨ ber method is commonly used to synthesize spherical colloidal silica; however, these methods have some disadvantages, such as complicated processes for the removal of sodium ions and expensive and energy-consuming raw materials such as tetraethoxysilane (TEOS). In this study, size-controlled spherical colloidal silica was synthesized from silicon metal at room temperature using an ultrasound process with hydrazine monohydrate as the solvent. Silicon metal dissolves easily in hydrazine monohydrate under ultrasound irradiation, and spherical colloidal silica can be synthesized by adding alcohol to this precursor solution. By changing the concentration or type of alcohol, size-controlled colloidal silica 20–200 nm in size could be easily obtained. In addition, finer and more monodisperse particles were produced by low-frequency ultrasound irradiation, which had a higher stirring effect at the particle formation stage. The present method is effective because size-controlled colloidal silica can be synthesized at room temperature using only silicon metal, hydrazine, and alcohol as raw materials, without complicated processes or expensive and energy-consuming raw materials such as TEOS or tetramethoxysilane (TMOS).

One-step functionalization and polymer grafting potential of green silica derived from rice husk ash

Green silica has been synthesized from rice husk ash which exempts the landfilling of agricultural waste and the requirement of higher temperature for digestion, unlike the conventional mode of silica synthesis making the process of precipitation and functionalization sustainable. An energy-efficient method of functionalization has been optimized for the synthesis of functionalized silica from rice husk ash via co-condensation. The potential for providing better reinforcement leads silica to be used as filler in composite manufacturing. To obtain a better silica-polymer interaction, nitroxide functionalized silica has been synthesized over three different types of silica samples using different processes. The nitroxide functionalities were introduced by thiol-ene reaction between 4-acryloyloxy(2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) and mercaptopropyl functionalized silica particles. The mercaptopropyl functionalized silica was synthesized by post-modification as well as co-condensation over commercial precipitated silica, commercial rice husk ash silica, and silica synthesized in the lab from sodium silicate obtained from rice husk ash. By comparing mercaptopropyl and nitroxide grafting density, it has been observed that the nitroxide loading highly depends on the method of functionalization and the co-condensed samples show higher nitroxide loading compared to the post-modified samples. The nitroxide functionalized samples were further subjected to polystyrene grafting, and the efficiency of surface nitroxide radicals in capturing the polymer radicals with respect to nitroxide loading was determined. The grafting density was observed to increase with the increase in conversion and the increase in the initiator-to-monomer ratio. However, the grafting density was observed to be saturated at some point despite having a higher surface area and surface nitroxide radicals. The study can be used to tune the surface nitroxide radical concentration and surface area for optimum polymer grafting for engineering applications.

Turbulence-assisted shear controllable synthesis of silicon oxide micro/nano particles using a counter axial-swirling impinging jet flow reactor

It has been recognised that turbulence shear can be used to effectively control and affect the synthesis of micro/nano particles. The present study focuses on turbulence-assisted shear controllable synthesis of silica (SiO2) micro/nano particles and investigates such shear controllable synthesis process using a counter axial-swirling impinging jet flow vortex flow reactor. Two counter swirling flow streams impinge in the reaction chamber to significantly intensify the local turbulence shear with the aid of ultrasound irradiation. The consequence of the turbulent shear leads to either the trapping of nano-particle nucleus into the turbulent eddies to form the aggregated micro/nana particles or the confinement of the growth of agglomerated micro/nano particles so as to form highly uniform and better morphological micro/nano particles. The experimental results have affirmed the postulation that the local turbulent shear generated by the turbulent eddies with the length scales down to the Kolmogorov length scale may directly interact with the aggregated SiO2 micro/nano particles, influencing the particle spherical morphology and size distribution. In addition, it has been found that synthesis performance can be further improved by intensifying the local turbulent shear through the ultrasound irradiation in the synthesis process. Both CFD simulation and experimental results clearly indicate the existence of the correlation in the synthesized SiO2 micro/nano particle characteristics with the local turbulence shear and mass transfer occurring in counter swirl impinge jet flow.

Continuous flow synthesis of hierarchical low silica X zeolite

Zeolites, renowned for their versatile applications in catalysis, adsorption, and ion exchange, have long been synthesized using conventional batch processes. However, the inherent limitations of these methods, such as resource-intensive conditions and inconsistent product quality, underscore the need for a sustainable and efficient approach. In this study, a continuous flow synthesis process was established for the synthesis of industrially important low silica X (LSX) zeolite using a tubular reactor. The synthesis gel was subjected to aging for 5 days at room temperature to facilitate nucleation and crystal growth combined with the fast-heating rate in a tubular reactor at 363 K & 1.1 atm., which in turn produces LSX after 40 min. The synthesized product was confirmed by the XRD, FE-SEM, EDS, XRF, TEM, and N2 adsorption-desorption; the data was compared with the LSX sample synthesized by batch process. The result implies that LSX prepared by continuous flow has a pure phase of LSX with the hierarchical structure, which provides better adsorption capacity of CO2 at 298 K up to 20 bar. Due to continuous flow synthesis, the crystallization time was reduced and faster kinetics which may be helpful for scale-up the process for LSX synthesis.

Custom-Design of Multi-Stimuli-Responsive Degradable Silica Nanoparticles for Advanced Cancer-Specific Chemotherapy.

Chemotherapy is crucial in oncology for combating malignant tumors but often encounters obatacles such as severe adverse effects, drug resistance, and biocompatibility issues. The advantages of degradable silica nanoparticles in tumor diagnosis and treatment lie in their ability to target drug delivery, minimizing toxicity to normal tissues while enhancing therapeutic efficacy. Moreover, their responsiveness to both endogenous and exogenous stimuli opens up new possibilities for integrating multiple treatment modalities. This review scrutinizes the burgeoning utility of degradable silica nanoparticles in combination with chemotherapy and other treatment modalities. Commencing the elucidation of degradable silica synthesis and degradation mechanisms, emphasis is placed on the responsiveness of these materials to endogenous (e.g., pH, redox reactions, hypoxia, and enzymes) and exogenous stimuli (e.g., light and high-intensity focused ultrasound). Moreover, this exploration delves into strategies harnessing degradable silica nanoparticles in chemotherapy alone, coupled with radiotherapy, photothermal therapy, photodynamic therapy, gas therapy, immunotherapy, starvation therapy, and chemodynamic therapy, elucidating multimodal synergies. Concluding with an assessment of advances, challenges, and constraints in oncology, despite hurdles, future investigations are anticipated to augment the role of degradable silica in cancer therapy. These insights can serve as a compass for devising more efficacious combined tumor treatment strategies.

Ordered Mesoporous Silica Delivering siRNA as Cancer Nanotherapeutics: A Comprehensive Review.

Nanosized mesoporous silica has emerged as a promising flexible platform delivering siRNA for cancer treatment. This ordered mesoporous nanosized silica provides attractive features of well-defined and tunable porosity, structure, high payload, and multiple functionalizations for targeted delivery and increasing biocompatibility over other polymeric nanocarriers. Moreover, it also overcomes the lacunae associated with traditional administration of drugs. Chemically modified porous silica matrix efficiently entraps siRNA molecules and prevents their enzymatic degradation and premature release. This Review discusses the synthesis of silica using the sol-gel approach and the advantages with different silica mesostructure. Herein, the factors affecting the synthesis of silica at nanometer scale, shape, porosity and nanoparticle surface modification are also highlighted to attain the desired nanostructured silica carriers. Additional emphasis is given to chemically modified silica delivering siRNA, where the silica nanoparticle surface was modified with different chemical moieties such as amine modified with (3-aminoropyl) triethoxysilane, polyethylenimine, chitosan, poly(ethylene glycol), and cyclodextrin polymer modification to attain high therapeutic loading, improved dispersibility and biocompatibility. Upon systemic administration, ordered mesoporous nanosized silica encounters blood cells, immune cells, and organs mainly of the reticuloendothelial system (RES). Thereby, biocompatibility and biodistribution of silica based nanocarriers are deliberated to design principles for smart and efficacious nanostructured silica-siRNA carriers and their clinical trial status. This Review further reports the future scopes and challenges for developing silica nanomaterial as a promising siRNA delivery vehicle demanding FDA approval.

Biomimetic Synthesis of Nanosilica by Deep Learning‐Designed Peptides and Its Anti‐UV Application

The silicifying peptide R5 (H‐SSKKSGSYSGSKGSKRRIL‐OH) derived from diatoms is extensively investigated, but the mechanism underlying silica synthesis by R5 or R5‐alike peptides is still poorly understood, limiting the design of silicifying peptides Herein, machine learning techniques are used to design peptides with silicifying functionality. Utilizing a comprehensive dataset of peptides and their corresponding silicification outcomes, a deep learning model based on antimicrobial peptide migration learning is created. This model exhibits the remarkable capability to accurately predict peptide sequences with a high potential for facilitating silica formation. A selection of artificially designed peptides can catalyze the biomimetic synthesis of nanosilica, some of which demonstrate better catalytic activity with a wider pH range and faster reaction rate compared with the peptide R5. Additionally, the designed peptide is used to wrap the model diatom Phaeodactylum tricornutum with nanosilica coatings, resulting in a significant enhancement in the UV resistance of cells. The new silicified peptides are highly significant for advancing the understanding of the silica synthesis mechanism in diatoms, and the encapsulation of P. tricornutum has potential benefits in the development of new biosensors.

Synthesis and characterisation of rice husk and palm fruit bunch silica: compositional, structural, and thermal analyses

Synthesis and characterisation of rice husk and palm fruit bunch silica: compositional, structural, and thermal analyses

Tunable Neuromorphic Switching Dynamics via Porosity Control in Mesoporous Silica Diffusive Memristors.

In response to the growing need for efficient processing of temporal information, neuromorphic computing systems are placing increased emphasis on the switching dynamics of memristors. While the switching dynamics can be regulated by the properties of input signals, the ability of controlling it via electrolyte properties of a memristor is essential to further enrich the switching states and improve data processing capability. This study presents the synthesis of mesoporous silica (mSiO2) films using a sol-gel process, which enables the creation of films with controllable porosities. These films can serve as electrolyte layers in the diffusive memristors and lead to tunable neuromorphic switching dynamics. The mSiO2 memristors demonstrate short-term plasticity, which is essential for temporal signal processing. As porosity increases, discernible changes in operating currents, facilitation ratios, and relaxation times are observed. The underlying mechanism of such systematic control was investigated and attributed to the modulation of hydrogen-bonded networks within the porous structure of the silica layer, which significantly influences both anodic oxidation and ion migration processes during switching events. The result of this work presents mesoporous silica as a unique platform for precise control of neuromorphic switching dynamics in diffusive memristors.

Effect of Y2O3 and different acids in PL response and fingerprint detection of SiO2:Dy3+,Eu3+

Synthesis of silica (SiO2) matrix doped with Dy3+ and Eu3+ was performed, and the combined effects of Y2O3 and different acids (HCl and HNO3) are studied. The resulting samples present different SiO2 -Y2O3 phases. The structures show granular-stack microstructures and irregular porosity. Samples exhibit the characteristics rare earths absorption bands and a decrement in UV region due to the presence of Y2O3. This phenomenon is related to the outstanding emissions. We are looking for luminescent silica phosphors (SiO2) doped with Dy3+ or Eu3+, and the combined effects of Y2O3 and different acids (HCl and HNO3) with the aim to obtain the right combination for the best possible PL emission and lifetime. These results display SiO2-Y2O3:Eu3+ powders as excellent candidates to be used as a luminescent material and for fingerprint detection.

Quality-by-Design Approach to Process Intensification of Bioinspired Silica Synthesis.

Characterizing nanomaterials is challenging due to their macromolecular nature, requiring suites of physicochemical analysis to fully resolve their structure. As such, their synthesis and scale-up are notoriously complex, especially when compared to small molecules or bulk crystalline materials, which can be provided a unique fingerprint from nuclear magnetic resonance (NMR) or X-ray diffraction (XRD) alone. In this study, we address this challenge by adopting a three-step quality-by-design (QbD) approach to the scale-up of bioinspired silica nanomaterials, demonstrating its utility toward synthesis scale-up and intensification for this class of materials in general. First, we identified material-specific surface area, pore-size distribution, and reaction yield as critical quality attributes (CQAs) that could be precisely measured and controlled by changing reaction conditions. We then identified the critical process parameters (CPPs) controlling bioinspired synthesis properties, exploring different process routes, incorporating commercial reagents, and optimizing reagent ratios, comparing silica properties against original CQA values to identify acceptable limits to each CPP. Finally, we intensified the synthesis by increasing reagent concentration while simultaneously incorporating the optimized CPPs, thereby modifying the bioinspired silica synthesis to make it compatible with existing manufacturing methods. We increased the specific yield from ca. 1.1 to 38 g/L and reduced the additive intensity from ca. 1 to 0.04 g/g product, greatly reducing both synthesis cost and waste production. These results identify a need for mapping the effects of critical process parameters on material formation pathways and CQAs to enable accelerated scale-up and transition from the lab to the market.

Characterization of Silica Nanoparticles from Pumice as an Aerogel Adsorbent

Pumice is often found around the banks of rivers, this stone is a type of igneous rock formed from volcanic eruptions. One of the compounds contained in pumice is silica. Therefore, the synthesis of silica nanoparticles from pumice using the sol gel method was used because it is simpler and more efficient in terms of cost and processing time. the initial step was by reacting pumice powder and NaOH at 70°C - 80°C then synthesized by adding 2M HCI to form a gel or white precipitate, soaking in ethanol, teos, hexane solutions was then synthesized to become an aerogel. Silica synthesis results into silica aerogels were characterized by FTIR and XRF. From FTIR silanol and siloxane functional groups were found, and the SiO2 composition increased to 93,299% after synthesis.

High‐Purity Template‐Free Mesoporous Silica Synthesized FROM Coal Fly Ash

AbstractThe study demonstrates a new method to create high‐purity mesoporous silica from coal fly ash without using structure‐directing agents. Divided into two stages, the process involves pre‐treating the ash with Na2CO3, calcination, cooling, washing, and drying to yield a dehydrated sample. Subsequently, silica synthesis occurs through an acid refluxing technique using thermally activated coal fly ash with Na2CO3. Key factors impacting synthesis include acid content and liquid‐to‐solid ratio. The study extensively employs various characterization methods like XRF, XRD, FTIR, and BET analysis, revealing a 99.1 % purity in silica content, a surface area of 793.51 m2/g, and a pore size of 3.9 nm. Optimal conditions for this synthesis involve 80 °C temperature, 2‐hour reaction time, 25 % hydrochloric acid concentration, and a 10 : 1 liquid‐to‐solid ratio. FTIR spectra demonstrate similarities between the obtained silica and commercial Sigma Aldrich silica. This innovative approach presents a promising avenue for generating top‐quality silica from coal fly ash, potentially diversifying applications across industries reliant on high‐performance silica materials.

Facile synthesis of magnetic-fluorescent iron oxide-geothermal silica core/shell nanocomposites via modified sol–gel method

Facile synthesis of magnetic-fluorescent iron oxide-geothermal silica core/shell nanocomposites via modified sol–gel method

Photooxidation of organic compounds by mesoporous silica functionalized with rose bengal

AbstractThe reuse of waste and the use of renewable materials are of great environmental and economic interest. With that in mind, the synthesis of mesoporous silica can be performed using rice husk ash, which is an industrial waste generated in large quantities. This mesoporous material can be functionalized with photoactive molecules, enabling application in photocatalysis. In this work, we used mesoporous silica nanoparticles functionalized with rose bengal dye (RB) for photooxidation reactions of organic molecules, such as the antibiotic cefuroxime 1‐acetoxyethyl ester (cefuroxime axetil). The characterization results showed the formation of one‐dimensional channels with uniform size and two‐dimensional hexagonal arrangement, with surface area and pore diameter of 230 m2 g−1 and 5 nm, respectively. The infrared and UV‐Vis spectroscopy indicated the functionalization of silica with photoactive molecules. Finally, SBA‐15/RB was applied for the photooxidation of ascorbic acid and antibiotic cefuroxime axetil under irradiation with green light, proving to be efficient for the degradation of cefuroxime axetil. Investigation of the reactive oxygen species involved in photodegradation showed that the photooxidation mechanism mainly involves singlet oxygen.

Synthesis of EDTA-Functionalized Silica Coated Nanomagnetite as a Cobalt(II) Ion Adsorbent

Synthesis of EDTA-Functionalized Silica Coated Nanomagnetite as a Cobalt(II) Ion Adsorbent

SYNTHESIS OF NANO-SILICA FROM LOA KULU RICE HUSK USING THE SOL-GEL METHOD

Silica is a material that is widely found in nature and is able to withstand corrosion attacks from corrosive environments. However, this natural material must be extracted to obtain high purity silica. Simple sol-gel method is used to solve the extraction problem (nano-silica with high purity). The natural materials used in this research come from organic materials, namely rice husks from the local area (Loa Kulu area). The main objective of this experiment is studying the effect concentration of HCl for crystalline size. The synthesis of silica was carried out with the preparation of ashes, then mixed with NaOH 7M until a solution of sodium silicate was produced. Silicate sodium solution was pressed with HCl 2M to form a silica gel with pH 7, 5, and 3 then was dried to produce silica powder. Silica powder was then burned at a temperature of 1000°C to produce silica with a crystalline phase. Based on the experiment, silica powder before calcination has amorphous phase and at any pH variation, the crystallite size calculated with the Debye Scherrer approach does not show any change the crystallite size by the variation of the silica gel’s pH. In addition, silica powder calcinated at 1000°C has amorphous and cristobalite phases and showed changes in crystal size after calculated with Debye Scherrer’s approach.