Synthesis Of Silica Nanoparticles Research Articles

A Novel and Economical Approach for the Fusarium Oxysporum Mediated Myco‐Synthesis of Mesoporous Floral‐Shaped Silica Nanoparticles from Coal Fly Ash Waste

AbstractNanotechnological applications involving the fabrication of potential nanomaterials and novel strategies for mitigation of contaminants have helped a lot in environmental cleanup. The chemical route for silica nanoparticle (NPs) synthesis using tetra ethyl oxy silicone and tetramethyl oxy silicone is expensive and energy intensive. Silica NPs synthesis from coal fly ash waste could prove to be economical. In this study, the investigators have used coal fly ash for silica NPs synthesis via a noble and economical approach. This biosynthetic approach involved two steps: (1) extraction of crude sodium silicate by using alkali treatment of fly ash and (2) the addition of crude sodium silicate to the supernatant of Fusarium oxysporum for fabrication of silica NPs. The developed silica NPs are analyzed by the analytical instruments where the microscopic techniques revealed 10–50 nm‐sized floral‐shaped mycogenic silica NPs. The X‐ray diffraction revealed the amorphous nature of the silica NPs with a broad spectrum starting from 8º and ending at 23º having centered at 13.1°. Fourier transform infrared spectroscopy, in region 400–1200 cm−1, exhibited three distinguishing bands for silica NPs. The current study reports a novel and effective method for the development of silica NPs with a high yield and purity of about 95%.

Green Synthesis of Silica Nanoparticles (Si-NPs) from Palm Oil Fuel Ash (POFA) and its Application to Purification Water: A Review

Abstract Increasing the volume of palm oil production impacts the amount of waste the palm oil industry produces. This waste, if handled properly, will have a positive impact on the environment. Boiler efficiency and energy value can be increased while reducing solid waste and fossil fuel emissions by using shells and fibres as fuel. However, burning biomass as boiler fuel leaves residue as palm oil fuel ash (POFA) and is generally thrown away. POFA contains silica and can be extracted and synthesized into silica nanoparticles (Si-NPs) by process engineering. Si-NPs derived from agricultural waste or renewable sources are environmentally friendly and have unique properties such as high surface area, adjustable pore diameter, and excellent chemical and thermal stability. These properties make Si-NPs ideal for water purification, and this paper reviews recent advances in the synthesis of Si-NPs using POFA, future research directions, and challenges in the application of Si-NPs for water purification. This review compiles information from research articles on the current synthesis of environmentally friendly Si-NPs as study material to develop and utilize POFA waste as a biomaterial in fabricating filtration membranes in water purification.

Mitoxantrone-Derivative Drug Structure-Directing Agent for the Synthesis of Magnetic Mesoporous Silica Nanoparticles for Breast Cancer Treatment

Mitoxantrone-Derivative Drug Structure-Directing Agent for the Synthesis of Magnetic Mesoporous Silica Nanoparticles for Breast Cancer Treatment

Mobility inhibition of arsenic in the soil: the role of green synthesized silica nanoparticles

The studies showed the effectiveness of green-synthesized SiO2NPs in mitigating the toxicity of Arsenic. Density Functional Theory (DFT) is a computational method used to determine electronic structure, energy gap, and toxicity prediction. Experimentally, silicon nanoparticles of 0 (S0) and 100% v/v (S100) were applied to the surface of the soil. 150 mL of Arsenic trioxide was applied twice at a rate of 0 (As0) and 3.2 g/mL (As3.2) at an interval of three weeks. Green synthesized SiO2NPs possessed a higher chemical potential (µ) and electrophilicity index; consequently, charges could be transferred and easily polarized. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of the green synthesized SiO2NPs enable them to donate electrons and complex with arsenic, reducing their bioavailability and toxicity. Evidence from the studies further showed that SiO2NPs had buffered the soil acidity and electric conductivity, posing a high binding site and reactivity with exchangeable cations and micronutrients due to their smaller energy gap. Furthermore, the catalytic activities of the soil enzymes dehydrogenase (DHA) and peroxidase (POD) were greatly increased, which enhanced the electrostatic interaction between the SiO2NPs and As.

Eco-friendly synthesis of amino and carboxyl-functionalized silica nanoparticles for enhanced adsorption of water pollutants

Green synthesised nanoparticles (NPs) have garnered significant attention as a rapidly expanding category of materials with diverse applications. In this context, plants are widely acknowledged as a highly favourable option for green synthesis due to their adherence to the eco-friendly pathway of NPs biosynthesis. The objective of green synthesis is to reduce the utilisation of hazardous chemicals. The utilisation of silica (SiO2) NPs, synthesised from biomass as adsorbents, has shown great potential particularly in removing toxic materials from environment. When it comes to adsorbing water pollutants, functionalized SiO2 NPs are seen as potential option. However, certain functional group onto the surface of SiO2 NPs have higher affinity towards a particular pollutant. In this work, a simple and eco-friendly synthesis method (using waste bamboo leaves) have been utilised for production of SiO2 NPs. Further, a silylating procedure was used to functionalize SiO2 NPs with amine (A-SiO2) and carboxyl groups (C–SiO2) for determining adsorption capabilities towards anionic and cationic dyes i.e., Naphthol green-B (NGB) and brilliant green (BG). The adsorption mechanism has been discussed in view of different adsorption isotherm models. According to batch investigations, the functionalized SiO2 NPs showed different behaviour for dyes depending upon nature of dyes and the functional groups. The results of the study revealed that A-SiO2 NPs were having adsorption capacity of 122.10 mg/g for anionic dye (NGB) while C–SiO2 NPs showed adsorption capacity of 114.41 mg/g for cationic dye (BG). Additionally, these NPs exhibit good recyclability up to 5 cycles of reuse. Novelty of this study is the reduced energy needs for the green synthesis of the SiO2 NPs using bamboo leaves and the effect of different functional groups on the adsorption capacity of the NPs. Overall, this study provides a sustainable, and reusable approach for effective dye removal from wastewater, addressing both environmental and economic problems.

Sustainable Approaches in Green Synthesis of Silica Nanoparticles Using Extracts of Chlorella and Its Application.

Silica nanoparticles, also known as SiO2 nanoparticles, have wider applications in biomedical, building, water treatment, agriculture, and food industries. It is used as an anticaking agent in the food industry, used to remove heavy metals from water, and used in cement-based materials. SiO2 nanoparticles synthesized by physical and chemical methods require high energy and use of toxic chemicals which is quite expensive, have a greater impact causing health-related issues, and have environmental side effects. Hence, there is a need to synthesize nanoparticles in an eco-friendly way. The biological or green synthesis method uses microbes, such as bacteria, fungi, algae, and plants for synthesizing nanoparticles. Algae contain natural biochemicals that act as reducing agents. These biomolecules are non-toxic as they are naturally occurring compounds and can be used to fabricate nanoparticles by avoiding the use of toxic chemicals in an eco-friendly method. In this study, silica nanoparticles were synthesized by green synthesis methods using microalgae extract. Further, the green synthesized silica nanoparticles were characterized using ultra violet-visible (UV-VIS) spectroscopy, Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray analysis (EDAX). The antimicrobial activity of the silica nanoparticles against E. coli was studied. This study revealed that the nanoparticles can be synthesized using green synthesis methods with low cost, less toxic chemicals, eco-friendly, and have antimicrobial activity against E. coli.

Positive Impact of Green Synthesized Silica Nanoparticles in Plant Growth Promotion and Physiological Responses of Eruca sativa Mill.

Positive Impact of Green Synthesized Silica Nanoparticles in Plant Growth Promotion and Physiological Responses of Eruca sativa Mill.

Amino acid‐decorated mesoporous silica nanoparticles loaded with titanocene derivatives for targeted anticancer studies

Nanostructured materials possess promising potential for cancer therapy through precise adjustment of their functionalization and physicochemical attributes. This study primarily focuses on the synthesis and characterization of mesoporous silica nanoparticles (MSN) that are functionalized with titanocene dichloride (a therapeutic agent) and one of several amino acids—cysteine, captopril, penicillamine, or methionine—utilizing 3‐aminopropyltriethoxysilane (AP) as a linker. This synthesis yielded four innovative metallodrug‐functionalized nanostructured materials (MSN‐AP‐Cys‐Ti, MSN‐AP‐Cap‐Ti, MSN‐AP‐Pen‐Ti, and MSN‐AP‐Met‐Ti), meticulously characterized using diverse analytical techniques such as X‐ray diffraction (XRD), X‐ray fluorescence (XRF), diffuse reflectance ultraviolet–visible (DR UV–Vis), Fourier transform infrared (FTIR), solid‐state nuclear magnetic resonance (NMR) spectroscopy, and transmission electron microscopy (TEM). The textural properties of the nanomaterials post‐functionalization displayed slight modifications, confirming the successful integration of the therapeutic agents. Evaluation of cytotoxicity in the breast cancer cell line MDA‐MB‐231, with the healthy cell line Hek‐293T as control via MTT assays, revealed the active nature of the functionalized silica‐based materials. The viability of both cell lines indicated a concentration‐dependent response to the materials. Among the tested systems, cysteine and captopril exhibited the highest activity concerning IC50relative to material concentration. The enhanced biological activity of higher functionalized nanosystems suggests a favorable cell internalization facilitated by the amino acid fragment. Additionally, qualitative DNA binding studies hinted at potential DNA adsorption on the surface of the metallodrug‐functionalized nanomaterials, forming DNA adducts where a strand of DNA covalently bonds to the metallodrug moiety. This was deduced from the hypsochromic shift in absorbance of the characteristic π–π* andn–π* transitions in DNA, which occurred from 1.01 to 0.76 and 1.26–0.19 following drug (MSN‐AP‐Cap‐Ti) interaction.

Synthesis and Evaluation of Mesoporous Silica Nanoparticle Catalyst Supports Prepared from South African Coal Fly Ash

The development of environmentally sustainable catalytic reaction systems for the oxidation of organic compounds has gained significant interest, with widespread application across various industries. This study investigates the suitability of mesoporous silica nanoparticles, synthesized from coal fly ash, as catalyst supports in the oxidation of veratryl alcohol, a compound that serves as a model to mimic the oxidation behavior of lignin-derived structures commonly found in biomass waste. A Cu(II) salicylaldimine complex was employed as the catalyst, with tert-Butyl hydrogen peroxide as the oxidant. Silica catalyst supports were synthesized from coal fly ash derived Na2SiO3 solutions. The effect of pre-dealumination of coal fly ash during Na2SiO3 preparation, variation of the surfactant in silica nanoparticle synthesis, and storage conditions of the catalyst supports on the performance of the coal fly ash derived silica catalyst supports were evaluated and compared to the performance of MCM-41 and SBA-15. The textural properties of the coal fly ash derived silica catalyst supports were notably influenced by the choice of surfactant used during its synthesis, while storage conditions affected the abundance of silanol groups necessary for successful catalyst immobilisation.Graphical

Kinetic Regularities of the Synthesis of Silica Nanoparticles by Heterogeneous Hydrolysis of Tetraethoxysilane Using L-Arginine as a Catalyst

Abstract The kinetics of the synthesis of silica nanoparticles (<50 nm) has been studied under the conditions of heterogeneous hydrolysis of tetraethoxysilane (TEOS) using L-arginine as an alkaline catalyst. The rates of silica formation have been determined in a temperature range of 10–95°C at catalyst concentrations of 6–150 mM. It has been shown that the activation energy of the process depends on catalyst concentration and varies in a range of 21.5–13.9 kJ/mol, while decreasing linearly with increasing concentration of L-arginine in the system. The criterion of maintaining the monodispersity has been estimated for SiO2 particles being grown “onto seeds.” The density of submicron-sized silica particles has been experimentally determined as depending on the annealing temperature. Within a temperature range of 200–1000°C, the particle density varies from 2.04 to 2.20 g/cm3.

A comparative pyrolysis study of tetraethoxysilane and tetraethoxymethane: Insight into congener substitution effects on pyrolysis chemistry of siloxane flame synthesis precursors

The pyrolysis of siloxane precursors, such as tetraethoxysilane (TEOS), is commonly employed in the flame synthesis and chemical vapor deposition of silica nanoparticles. In this work, the flow reactor pyrolysis of TEOS is studied using gas chromatography (GC) and synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS), and the congener substitution effects from the central C atom to the central Si atom are investigated through comparison with its hydrocarbon counterpart tetraethoxymethane (TEOM). Pyrolysis models of TEOS and TEOM are constructed and validated against the measured results. Modeling analysis, including rate of production analysis and sensitivity analysis, provides insights into chemistry in fuel consumption and product formation. In contrast, the observations of silicon-containing products in SVUV-PIMS experiments provide evidence for crucial decomposition pathways of TEOS. It is observed that TEOS exhibits significantly higher stability than TEOM under pyrolysis conditions. The most abundant products in the pyrolysis of TEOS and TEOM are ethylene and ethanol, and TEOS produces more hydrocarbon products than TEOM. The lower pyrolysis reactivity of TEOS is attributed to the slower unimolecular decomposition reaction which dominates the decomposition of TEOS than TEOM. This can be explained by the hindrance of the extremely strong Si-O bond resulting from the significantly different electronegativity between Si and O. The higher initial decomposition temperature of TEOS enhances the contribution of other decomposition channels, such as C-C bond dissociation and H-abstraction reactions, in TEOS consumption. This leads to the abundant formation of hydrocarbon productions such as methane, ethane, and acetaldehyde. As the main pyrolysis product, the ethanol produced by TEOM pyrolysis is four times that of TEOS due to the congener substitution effects. The ethanol formation pathway in TEOS pyrolysis is different from that in TEOM pyrolysis, which is mainly formed via a newly proposed multi-step mechanism, resulting in a lower yield in TEOS pyrolysis.

Synthesis of Silica Nanoparticles: A Review

Synthesis of Silica Nanoparticles: A Review

Characterization and antimicrobial Properties of Cotton Fabric Loaded with green Synthesized Silica Nanoparticles

During the past decade, improvement in the functionality of textile materials has become an important research field due to their significant health and safety benefits. Here we report, simple and cost-effective green synthesis of silica nanoparticles from fibrous residue of sugarcane bagasse followed by investigating the applicability on cotton fabric. The characteristics of synthesized nanoparticles were determined by techniques including FTIR (exhibited characteristic peak at 791.01 attributed to vibration of Si-O and the absorption band at 1072.48 cm-1 owing to asymmetric vibration of Si-O-Si confirming the formation of SNPs), SEM (40±2nm), and XRD (Examined spectra with JCPDS 36-1451 indicate well-defined peaks of Silicon Oxide). Debye Scherrer equation was used to calculate the mean crystallite size (19.79 nm) of powder Silica NP sample at the full width half maximum (FWHM) of the diffraction peaks of 2Ɵ positions. Applicability of synthesized nanoparticles was determined by assessing thermal stability and antimicrobial property of treated and untreated cotton fabric. It was observed that silica nanoparticles coated fabric showed substantial thermal stability at 1 % Silica NPs comparatively treated with 2% and 3% silica NPs due to clustering phenomena. Antimicrobial property, confirmatory test as positive control of treated fabric shown substantial increased in antibacterial activity in solutions containing silica NPs as compared to the ethanol solution. Moreover, 76 green profiling score of synthesized method was evaluated by Analytical Eco-Scale tool.

Green synthesis of rice straw-derived silica nanoparticles by hydrothermal process for antimicrobial properties and effective degradation of dyes

Rice straw is considered a major agricultural waste that has become a major threat to the environment. However, waste valorization of rice straws is a major challenge for the whole world. Therefore, this research aimed to utilize the different varieties of rice straw including Parmal rice straw (PRS), and Basmati rice straw (BRS) for the synthesis of silica nanoparticles (SiNPs) using hydrothermal autoclave method to precisely modify the particle size, and distribution, morphology and purity. This method uses water as a reaction medium under high temperature and pressure, which results in energy savings and reduced chemical waste compared to traditional methods. Furthermore, SiNPs were characterized using different analytical techniques. SEM showed the rough, compact, and highly ordered surface for both samples, while the SNP exhibited irregular shapes and rough surfaces. Rice straw powder revealed major functional groups at 787 cm−1, 1461 cm−1, and 2919.10 cm−1. BRS and PRS showed thermal stability up to 380 ℃ and 250 ℃, respectively. The particle size of BRS and PRS were found to be 112.47±1.23 nm and 114.98±1.23 nm, respectively. PRS-SiNPs showed the effective dye reduction ability for anthraquinone (96.79%± 0.39) and alizarin yellow (92.63%± 0.17) in 30 min. Additionally, the SiNPs exhibited potential bactericidal activity against Staphylococcus aureus and Escherichia coli in terms of zone of inhibition. Overall, the SiNPs synthesized from PRS demonstrated superior photocatalytic efficiency in the reduction of dyes compared to those synthesized from BRS.

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.

Multifactorial Investigation of Silica Nanoparticle Synthesis through Ultrasonic Spray Pyrolysis for Controlled Morphology and Diameter

Multifactorial Investigation of Silica Nanoparticle Synthesis through Ultrasonic Spray Pyrolysis for Controlled Morphology and Diameter

Itaconic Acid Cross-Linked Biomolecule Immobilization Approach on Amine-Functionalized Silica Nanoparticles for Highly Sensitive Enzyme-Linked Immunosorbent Assay (ELISA).

Biomolecule immobilization on nanomaterials is attractive for biosensors since it enables the capture of a higher concentration of bioreceptor units while also serving as a transduction element. The technique could enhance the accuracy, specificity, and sensitivity of the analytical measurements of biomolecules. However, it was found that the limitation in chemically binding biomolecules on nanoparticle surfaces could only cross-link between the C-terminal and N-terminal. Here, we report the facile one-step synthesis of amine-functionalized silica nanoparticles (AFSNPs). (3-Aminopropyl)triethoxysilane was used as a precursor to modify the functional surface of nanoparticles via the Stöber process. The biomolecules were immobilized to the AFSNPs through itaconic acid, a novel cross-linker that binds between the N-terminal and N-terminal and potentially improves proteins and nucleic acid immobilization onto the nanoparticle surface. The newly developed immobilization approach on AFSNPs for biomolecular detection enhanced the efficiency of ELISA, resulting in increased sensitivity. It might also be easily used to identify different pathogens for clinical diagnostics.

Synthesis and Characterization of Silica Nanoparticles Derived from Tea Factory Generated Wood Ash

India is the second most prolific tea producing nation in the world, which consumes 82% of its tea production, accounting for 19.5% of global tea consumption. Despite the improvement in technology, employing wood to produce heat has been a vital element of tea processing for generations. Many tea specialists experience that it adds a particular fragrant touch to the finished tea product. However, the management of wood ash generated by tea factories is a significant concern due to the large amount of wood burned during tea processing. Therefore, transportation and effective disposal of these large quantities of wood ash is a great challenge. Hence, this study aimed to effectively transform wood ash into a valuable product, nano silica particles so as to explore the scope for its better utilization in various applications. A series of experiments were carried out to optimize the parameters in the sol-gel technique for synthesizing silica nanoparticles from wood ash. Further, the synthesized nano silica particles were characterized by employing transmission electron microscopy (TEM) and X-ray diffraction (XRD). The standard operational protocol developed through this study demonstrated that wood ash can be effectively converted to silica nanoparticles in the size range of 20-50 nm, spherical in form with crystalline properties. Overall, the results of this work highlights the possibility of utilizing tea factory generated wood ash into silica nanoparticles with an immense potential for varied applications without environmental hazards.

Development of amine-functionalized fluorescent silica nanoparticles from coal fly ash as a sustainable source for nanofertilizer

Scaling up the synthesis of fluorescent silica nanoparticles to meet the current demand in diverse applications involves technological limitations. The present study relates to the hydrothermal synthesis of water-soluble, crystalline, blue-emitting amine-functionalized silica nanoparticles from coal fly ash sustainably and economically. This study used tertiary amine (trimethylamine) to prepare amine-functionalized fluorescent silica nanoparticles, enhancing fluorescence quantum yield and nitrogen content for nanofertilizer application. The TEM and FESEM studies show that the silica nanoparticles have a spherical morphology with an average diameter of 4.0 nm. The x-ray photoelectron and Fourier transform infrared spectroscopy studies reveal the presence of the amine group at the surface of silica nanoparticles. The silica nanoparticles exhibit blue fluorescence with an emission maximum of 454 nm at 370 nm excitation and show excitation-dependent emission properties in the aqueous medium. With the perfect spectral overlap between silica nanoparticle emission (donor) and chlorophyll absorption (acceptor), fluorescent silica nanoparticles enhance plant photosynthesis rate by resonance energy transfer. This process accelerates the photosynthesis rate to improve the individual plant’s quality and growth. These findings suggested that the fly ash-derived functionalized silica nanoparticles could be employed as nanofertilizers and novel delivery agents.

Preliminary Study on the Modification of Quantum Dots/Geothermal Silica Nanocomposites with Breast Cancer Antibody (MUC-1)

In this research, a silica-based nanosensor is synthesized using the sol-gel method and subsequently modified with quantum dots and MUC-1 antibody to detect MCF7, a cell line commonly found in breast cancer. Synthesis of silica nanoparticles was conducted through the sol-gel process using NaOH and HCl. The characterization using surface area analysis shows that geothermal silica based nanoparticles exhibit specific size of 31.2 nm with specific surface area of 192.37 m2/g. The nanoparticles were then modified using Cd-based Carboxyl Quantum dots to give fluorescence properties, obtaining SiNP@QD. Characterization was performed using UV-Vis and fluorescence spectroscopy to understand the photostability of nanoparticles in PBS buffer in various concentrations. The fluorescent nanoparticles were then immobilized with MUC-1 antibody and the successful conjugation was confirmed with FTIR showing peaks at 1548 and 1637 cm−1 corresponding to the amide I and amide II stretching vibration, respectively. The MUC-1 antibody modified silica nanoparticles is potential to be applied as nanosensor for the optical detection of MCF-7 cell line as one of breast cancer biomarkers.