Synthesis Of Silica Nanoparticles Research Articles

Facile synthesis of monodispersed mesoporous silica nanoparticles with ultra-large mesopores through a NaBH4-assisted hydrothermal process

This work reports the facile synthesis of monodispersed ultra-large mesopore mesoporous silica nanoparticles (ULP-MSNs) through a new and simple NaBH4-assisted hydrothermal process (NAH process). Such preparation of ULP-MSNs enables the small mesopore size (<3 nm) of as-prepared conventional MSNs to be effectively enlarged to over 20 nm. The synthetic parameters were systematically studied, and it was shown that the initial ethanol added in the synthesis mixture (1st ethanol), NaBH4, HCl(a.q.) and the ethanol added in the mixture (2nd ethanol) during the hydrothermal (HT) process and HT conditions play synergistic roles in enlarging mesopores by NAH process. We also revealed the mesopore-enlargement mechanism. By this method, the resultant ULP-MSNs possess tunable ultra-large mesopore sizes (18–31 nm), monodispersed spherical morphology, and controllable particle sizes (105–268 nm). The method presented here could effectively enlarge and adjust the mesopores of the MSNs. We supposed our approach may provide a platform of nanotechnology for the preparation of porous silica materials with adjustable mesopore sizes, which will be promising for practical applications.

Synthesis of Silica Nanoparticles Doped with Zinc Cation to Remove Bacteria DNA Harboring Antibiotic Resistance Genes from Aqueous Solution

This study investigated removing bacteria DNA from an aqueous solution using silica oxide nanoparticles doped with zinc cation (SiO2 @Zn2 + ). The authenticity of the adsorbent was confirmed by scanning electron microscopy (SEM) coupled with energy-dispersive x-ray spectroscopy (EDX). Adsorption studies involving two operating conditions (time-concentration profile and adsorbent dose) showed increased removal efficiency during the adsorption of bacteria DNA by SiO2 @Zn2 + . Therefore, SiO2 @Zn2 + may be a promising adsorbent that can tackle the consequences of ARGs infected water

Evaluation of the performance of concrete by adding silica nanoparticles and zeolite: A method deviation tolerance study

Researchers have conducted extensive research to develop concretes with improved properties and suitable for harsh environments. The use of nanomaterials to improve the performance of concrete is one of the promising methods for developing optimized concrete. However, the non-uniform distribution of nanoparticles in the concrete matrix limits the reproducibility of the behavior of concretes studied, particularly in industrial or practical environments. The high surface energy of nanoparticles, limitations, and lack of standardization of the production process are responsible for this phenomenon. Addressing this challenge, this study aims to investigate practical implementation conditions of silica nanoparticle and zeolite reinforced concrete. The study examines deviations from the base method, involving synthesized silica nanoparticles via the sol-gel method as the main additive, alongside zeolite as a representative of pozzolanic materials. By examining four parameters influencing the behavior of concrete over a period of 7 days and 180 days, as well as conducting experiments in parallel groups to simulate the practical environment, this study attempted to improve the reproducibility of concrete with silica nanoparticles and zeolites improved behavior. As a result of the study, it was found that the presence of silica and zeolite nanoparticles in 7-day concrete weakens and improves the properties of the concrete by − 10% and + 3%, respectively, for concrete after 7 days, and this effect increases by + 30% and + 93% for concrete after 180 days. This showed that there is a significant correlation between the healing effects of these substances and the amount of time they have been hydrated. Furthermore, concrete containing silica nanoparticles performs 35% better than the control sample. In contrast, concrete containing silica nanoparticles and zeolite provided a 165% improvement over the control sample. Using a correlation analysis of the effects of different parameters on the output performance of 7-day and 180-day concrete, this study presents a more detailed analysis of improved concrete response.

Hexamethyldisiloxane pyrolysis: Probing H-atom initiation by femtosecond two-photon LIF

Previous experiments have led to the hypothesis that pyrolysis of silica nanoparticle precursors carried in an inert central gas jet surrounded by a laminar flame is initiated not by thermal decomposition (the measured jet temperatures are too low for pyrolysis), but by reactions with H-atoms diffusing from the surrounding flame into the jet. The current work tests this hypothesis using femtosecond two-photon laser-induced fluorescence (fs-TPLIF) to image H-atom concentrations in the same flame configuration as the previous experiments. Methane flames (ϕ = 0.83, 1.01 and 1.13) were generated using a multi-element diffusion (Hencken) burner equipped with a central tube through which the N2 jet was introduced. The fs-TPLIF line imaging showed significant concentrations of H-atoms in the nitrogen jets at heights above the burner (HAB) close to the methane flame front. The measurements indicate radial diffusion of the H atoms from the flame to the jet is significant. The H-atom concentrations in the jet increased with increasing stoichiometry of the methane flame. Additional experiments were performed with hexamethyldisiloxane entrained in the central jet flow. In each case, a diffusion flame producing silica nanoparticles was established at the boundaries between the central jet and the methane flames. The 2D H-atom images showed a transition from over-ventilated diffusion flames to under-ventilated diffusion flames with increasing equivalence ratio. Furthermore, the fs-TPLIF profiles show a significant production of H-atoms within the jet when the surrounding flame is lean. This knowledge contributes to a deeper understanding of the underlying mechanisms governing these synthesis flame systems and opens avenues for advancing silica nanoparticle synthesis techniques.

Green synthesis and characterization of Halymenia floresia-mediated silica nanoparticles with antibacterial potential for removal of heavy metals from water

Green synthesis and characterization of Halymenia floresia-mediated silica nanoparticles with antibacterial potential for removal of heavy metals from water

Electronic structure and chemical states of green synthesized silica nanoparticles from biomasses

Silica nanoparticles (SiO2 NPs) were synthesized from the sugarcane bagasse (SB), pinewood stem (PS), walnut shell (WS), and rice husk (RH) using ambient burning, hydro-ball-milling, filtration, and post-annealing at 650 °C. The broadened XRD peak pattern (2θ = 22°) indicates the amorphous nature of all four samples, further confirmed by the circles of the SAED pattern. Microscopic images (snap-shots, SEM, TEM) revealed the agglomeration of SiO2 NPs with an average grain size of 40–80 nm. All samples' bandgap (Eg) was found in the 5.69–5.78 eV range determined from the Tauc's plot. The symmetric stretching of O–Si–O at 440 cm−1, Si–O at 880 cm−1, and asymmetric stretching of Si–O–Si peaks at 1062 cm−1 indicate the formation of polymorphic SiO2 NPs. Electronic and chemical states of SiO2 NPs were investigated by X-ray photoelectron spectroscopy (XPS), and the chemical bonding of SiOx and Si–O–Si occurred at 99.5 eV and 528.6 eV, respectively. Silicon (Si) concentration was observed to be ∼14.35 %, ∼18.88 %, ∼21.25 %, and ∼9.5 %, estimated from core-level XPS analysis. The pinewood stem extracted SiO2 NPs were observed to have a regular spherical shape with a size of 40 nm. The different atomic concentration of Si in all samples establishes their utilization in medical and industrial applications.

Upscale Synthesis of Magnetic Mesoporous Silica Nanoparticles and Application to Metal Ion Separation: Nanosafety Evaluation.

The synthesis of core-shell magnetic mesoporous nanoparticles (MMSNs) through a phase transfer process is usually performed at the 100-250 mg scale. At the gram scale, nanoparticles without cores or with multicore systems are observed. Iron oxide core nanoparticles (IO) were synthesized through a thermal decomposition procedure of α-FeO(OH) in oleic acid. A phase transfer from chloroform to water was then performed in order to wrap the IO nanoparticles with a mesoporous silica shell through the sol-gel procedure. MMSNs were then functionalized with DTPA (diethylenetriaminepentacetic acid) and used for the separation of metal ions. Their toxicity was evaluated. The phase transfer procedure was crucial to obtaining MMSNs on a large scale. Three synthesis parameters were rigorously controlled: temperature, time and glassware. The homogeneous dispersion of MMSNs on the gram scale was successfully obtained. After functionalization with DTPA, the MMSN-DTPAs were shown to have a strong affinity for Ni ions. Furthermore, toxicity was evaluated in cells, zebrafish and seahorse cell metabolic assays, and the nanoparticles were found to be nontoxic. We developed a method of preparing MMSNs at the gram scale. After functionalization with DTPA, the nanoparticles were efficient in metal ion removal and separation; furthermore, no toxicity was noticed up to 125 µg mL-1 in zebrafish.

Synthesis of core-shell magnetic mesoporous silica nanoparticles to disperse amine functionalities for post-combustion carbon dioxide capture

BackgroundPost-combustion capture technology appears a suitable approach to reduce the emission of CO2 by power plants. The use of solid sorbents would permit to overcome the limitations of the well-established liquid amine-based absorption process. In particular, mesoporous silica materials have been proposed as suitable sorbents especially if functionalized with amines. MethodsThe properties of as-synthesized (by using dodecylamine as synthesis amine) and calcined hexagonal mesoporous silica (HMS), impregnated or not with tetraethylenepentamine (TEPA), were studied. Magnetite (Fe3O4) nanoparticles were specifically used to obtain HMS core-shell nanoparticles in order to investigate the effect of the magnetite core on CO2 uptake capability. CO2 uptake measurements were carried out on all HMS and core-shell particles. Furthermore, Transmission Electron Microscopy (TEM) images, Fourier Transform Infrared (FTIR) spectra and N2 adsorption/desorption measurements allowed analyzing some important properties of the sorbent particles, such as particle aggregation, incorporation and dispersion of amines, surface area, pore volume and pore size distribution. Significant FindingsThe best performance in terms of chemical CO2 uptake was obtained on core-shell material, calcined and impregnated with TEPA (about 89 mg/g), but also the as prepared core-shell sample impregnated with TEPA seems promising since the synthesis dodecylamine sites can be activated during the impregnation process.

The amount of improvement and therapeutic effect of sports health by increasing the viscosity of peach juice through reverse osmosis and polymer membrane

In this study, the performance of polyamide membranes embedded with synthesized silica nanoparticles was evaluated for pomegranate juice concentration using the reverse osmosis (RO) process. The research aims to explore the potential therapeutic benefits and measurable improvements in sports health achieved by employing RO and a polymer membrane to enhance the viscosity of peach juice. The membranes utilized in this study feature a multi-layer structure comprising a non-woven polyester layer for strength, a sulfone polyether polymer sheet, and a polyamide layer synthesized through the copolymerization of m-phenylenediamine and benzene tricarboxylic chloride. To enhance the membrane properties, silica nanoparticles were incorporated into the second layer. The experiment was designed using Design Expert software, considering three parameters: weight percentage of polyether sulfone at three levels (12%, 16%, and 20%), weight percentage of silica nanoparticles at three levels (0%, 0.1%, and 0.2%), and the process pressure at three levels (20, 25, and 30 bar). The optimal membrane configuration obtained from this experimental design consisted of a sulfone polyether polymer content of 16%, silica nanoparticles concentration of 2%, and a working pressure of 23.24 bar. Furthermore, the findings of this study suggest that the application of polymer materials and nanoparticles for membrane modification holds potential benefits for the juice industry in the future. However, it is essential to consider the wide range of factors that can influence the properties of nanocomposite membranes.

Sustainable economic production of silica nanoparticles from rice husks for adsorptive removal of anionic and cationic dyes

The present study explores a novel microwave-assisted (MW) approach for advancing the sol-gel synthesis of silica nanoparticles from rice husk (RSN) to mitigate methylene blue (MB) and congo red (CR). According to physico-chemical and yield analysis, 50 min of MW calcination produced a high yield of 92 % RSN (RSN50) with a high surface area (208 m2/g). Under optimized conditions, the maximum adsorption capacities of MB and CR on RSN50 were 48.1 mg/g (at pH 5.6, Langmuir model) and 58.5 mg/g (at pH 2, Hills model), respectively. The MB adsorption kinetics on RSN50 followed a pseudo-second-order indicating chemisorption while CR adsorption on RSN50 followed a pseudo-first-order mechanism and positive ΔG signifying non-spontaneity. A regeneration study for 5 consecutive cycles showed retention of % dye removal capacity. The cost assessment showed a profit when compared to commercial silica nanoparticles proposing an efficient, economical, and sustainable substitute for varied applications.

Combinatorial treatment using bevacizumab/pemetrexed loaded core-shell silica nanoparticles for non-small cell lung cancer

ABSTRACT Non-small cell lung cancer (NSCLC) is a life-threatening cancer associated with a higher mortality rate. Despite promising results shown by combination therapies, there remains a need for efficient drug delivery materials capable of combining various drugs, imaging agents, and targeting agents to enhance treatment efficacy. In this study, we present the synthesis of novel core-shell hollow mesoporous silica nanoparticles (@MSN) with bimodal porosity and a large surface area (694 m2/g) to facilitate targeted drug delivery for NSCLC treatment. The hollow core-shell structure enables the loading of a substantial quantity of the pemetrexed drug, up to 839 µg/mg, with a sustained release of 20% within 48 h. The MSN is surface functionalised with amino and carboxyl groups to accommodate an imaging agent and facilitate the attachment of the targeting drug bevacizumab. These particles exhibit rapid uptake by both A549 and PC-9 cells. Moreover, the targeting by bevacizumab leads to higher cytotoxicity within 48 h and induces apoptosis more effectively than the non-functionalised samples. As a versatile drug delivery platform, the hollow core-shell MSN demonstrated in this study holds great potential for various drug delivery applications.

Synthesis of novel metal silica nanoparticles exhibiting antimicrobial potential and applications to combat periodontitis

Periodontitis is a severe form of gum disease caused by bacterial plaque that affects millions of people and has substantial worldwide health and economic implications. However, current clinical antiseptic and antimicrobial drug therapies are insufficient because they frequently have numerous side effects and contribute to widespread bacterial resistance. Recently, nanotechnology has shown promise in the synthesis of novel periodontal therapeutic materials. Nanoparticles are quickly replacing antibiotics in the treatment of bacterial infections, and their potential application in dentistry is immense. The alarming increases in antimicrobial resistance further emphasize the importance of exploring and utilizing nanotechnology in the fight against tooth diseases particularly periodontitis. We developed 16 different combinations of mesoporous silica nanomaterials in this study by ageing, drying, and calcining them with 11 different metals including silver, zinc, copper, gold, palladium, ruthenium, platinum, nickel, cerium, aluminium, and zirconium. The antibacterial properties of metal-doped silica were evaluated using four distinct susceptibility tests. The agar well diffusion antibacterial activity test, which measured the susceptibility of the microbes being tested, as well as the antibacterial efficacy of mesoporous silica with different silica/metal ratios, were among these studies. The growth kinetics experiment was used to investigate the efficacy of various metal-doped silica nanoparticles on microbial growth. To detect growth inhibitory effects, the colony-forming unit assay was used. Finally, MIC and MBC tests were performed to observe the inhibition of microbial biofilm formation. Our findings show that silver- and zinc-doped silica nanoparticles synthesized using the sol-gel method can be effective antimicrobial agents against periodontitis-causing microbes. This study represents the pioneering work reporting the antimicrobial properties of metal-loaded TUD-1 mesoporous silica, which could be useful in the fight against other infectious diseases too.

Eco-friendly Synthesis and Characterization of Amorphous Nanosilica from Rice Husk

Background: A significant amount of rice production waste is rice husk. It is not humifiable and turns into a significant environmental pollutant if not properly utilized. Rice husk contains silica nanoparticles, which is a major inorganic component. High purity amorphous silica nanoparticles can thus be produced using simple thermo-chemical procedures without polluting the environment by cutting out the release of carbon dioxide during the process. Methods: A study was carried out to extract amorphous silica nanoparticles from rice husk ash using an environmentally benign chemical process. Utilising a variety of material characterization techniques viz., X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDS) and Particle size analyser (PSA), the extracted nanoparticles properties were confirmed. Result: The amorphous behaviour of the silica sample was confirmed using transmission electron microscopy-selected area electron diffraction patterns and X-ray diffraction analyses, whilst siloxane and silanol groups were primarily discovered using Fourier-transform infrared spectroscopy. Images obtained using scanning electron and transmission electron microscopy showed initial nanoparticles to be present along with secondary microparticles, possibly as a result of their agglomeration. The extracted amorphous silica has particles with an average diameter of 35 nm. This synthesized silica nanoparticles can be used in agriculture, nano-additives, microelectronics, sensors and in other fields.

Biocompatible nanoscale silica particles fabricated from aminopropyltriethoxysilane functionalized brick ash induced versatile pesticidal activity

The present study is aimed to evaluate pesticidal activity and biocompatibility including ecotoxicity of functionalized silica nanoparticles that synthesized by simple, in vitro, green technology principles. Sol-gel method was adopted for the synthesis of silica nanoparticles and was functionalized by Aminopropyltriethoxysilane (APS), characterized and confirmed the uniform, monodispersive, highly stable particles with the size range of 10–200 nm. The synthesized Nano silica was screened against the developmental stages of Spodoptera litura. Pesticidal study revealed that the functionalized nanoparticles were effective against all the life stages of the insect by recording high mortality and the drastic reduction in the larval, pupae, adult emergence, and adult longevity stages. The ecotoxic effect of synthesized nano-silica was tested on soil parameters, growth parameters of Arachis hypogaea, and compatibility with Trichoderma viride. This study revealed there was no toxic effect on soil, growth parameters of Arachis hypogaea, and most significantly the growth of Trichoderma viride was not inhibited. A biocompatibility study was done by using Zebrafish and Rabbit model. The study divulges there was no toxic effect on all the developmental stages of the Embryo. Further, the nanoparticles did not exhibit any dermatotoxicological effect which confirmed no signs and symptoms of inflammation. Nano-silica emerges as a promising eco-friendly and non-toxic substitute for conventional insecticides. Its utilization has the potential to augment both environmental preservation and economic prosperity on a national scale. Furthermore, the integration of silica-based nanoparticles with biocidal agents demonstrates notable biocompatibility and the capacity to hinder bacterial adhesion.

Novel Aerosol‐Based Approach toward Mesoporous Silica Nanoparticles

This study introduces a novel gas‐phase method for the synthesis of mesoporous silica nanoparticles (MSNs). The method is a two‐step templating approach by first forming silicon‐coated carbon structures in a hybrid microwave‐plasma/hot‐wall reactor followed by an annealing step to produce mesoporous silica with distinct nanostructure and porosity. Two different (sacrificial) carbonaceous templates have been prepared (plasma reactor) and coated (hot‐wall reactor), 2D few‐layer graphene (FLG) flakes and soot‐like fractal aggregates. Results show that the wall thickness of the porous silica structures can be adjusted by changing the concentration of the silicon precursor (monosilane). High monosilane concentrations, however, result in solid silica particles after annealing. Using soot‐like particle templates permitted to control of the shell thickness of the hollow porous particles, while the FLG template results in ultrathin silica sheets after heat treatment. The pore volume and specific surface area increase up to 263 m2 g−1 and 0.6 cm3 g−1, respectively, by the formation of hollow porous particles. An adsorption study on carbamazepine reveals up to ≈86% removal. The gas‐phase aerosol‐based template method presented here offers scalability and versatility, and it is capable of producing MSNs with a controlled structure and porosity by modifying the carbonaceous templates.

Time dependent size control of sodium hydroxide catalyzed sol-gel synthesized silica nanoparticles modified with organosilane molecules by post-grafting

Time dependent size control of sodium hydroxide catalyzed sol-gel synthesized silica nanoparticles modified with organosilane molecules by post-grafting

Toxicity of Sol-Gel Synthesized Silica Nanoparticles: Insights from Cellular and Model Organism Studies

Toxicity of Sol-Gel Synthesized Silica Nanoparticles: Insights from Cellular and Model Organism Studies

A novel and economical approach for the synthesis of short rod-shaped mesoporous silica nanoparticles from coal fly ash waste by Bacillus circulans MTCC 6811.

Coal fly ash (CFA) is an industrial byproduct produced during the production of electricity in thermal power plants from the burning of pulverized coal. It is considered hazardous due to the presence of toxic heavy metals while it is also considered valuable due to the presence of value-added minerals like silicates, alumina, and iron oxides. Silica nanoparticles' demands and application have increased drastically in the last decade due to their mesoporous nature, high surface area to volume ratio, etc. Here in the present research work, short rod-shaped, mesoporous silica nanoparticles (MSN) have been synthesized from coal fly ash by using Bacillus circulans MTCC 6811 in two steps. Firstly, CFA was kept with the bacterial culture for bioleaching for 25 days in an incubator shaker at 120rpm. Secondly, the dissolved silica in the medium was precipitated with the 4M sodium hydroxide to obtain a short rod-shaped MSN. The purification of the synthesized silica particle was done by treating them with 1M HCl at 120 °C, for 90min. The synthesized short rod-shaped MSN were characterized by UV-vis spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Particle size analyzer (PSA), Field emission scanning electron microscopy (FESEM), and transmission electron microscope. The microscopic techniques revealed the short rod-shaped mesoporous silica nanoparticles (MSN) for the final nano-silica, whose size varies from 40 to 80nm, with an average size of 36 ± 5nm. The XRD shows the crystalline nature of the synthesized MSN having a crystallite size of 36nm. The FTIR showed the three characteristic bands in the range of 400-1100cm-1, indicating the purity of the sample. The energy dispersive X-ray (EDX) showed 53.04 wt% oxygen and 43.42% Si along with 3.54% carbon in the final MSN. The particle size analyzer revealed that the average particle size is 368.7nm in radius and the polydispersity index (PDI) is 0.667. Such a novel and economical approach could be helpful in the synthesis of silica in high yield with high purity from coal fly ash and other similar waste.

Controllable Synthesis of Hollow Silica Nanoparticles Using Layered Double Hydroxide Templates and Application for Thermal Insulation Coating.

The innovative hollow silica nanoparticle (HSN) material possesses substantial potential for application in the insulation field. The size and shell thickness of HSN are crucial factors in determining their inherent properties, which, in turn, impact their applicability. This research presents a facile approach to synthesizing HSN in which sodium silicate (Na2SiO3) was utilized as the silica precursor that can be directly deposited onto layered double hydroxide (LDH) nanoparticles without the utilization of any surfactant. A subsequent acid treatment was used to eliminate the templates, resulting in the formation of an HSN devoid of mesopores in silica shells. By utilizing various sizes of LDH cores, obtainable via coprecipitation followed by hydrothermal treatment, we were capable of successfully synthesizing the hollow particles with adjustable diameters ranging from 50 to 200 nm. In addition, the shell thickness is varied from 6.8 to 22.5 nm by varying the silicate solution concentration. Results demonstrate that prepared HSNs have low thermal conductivity and high reflectance in the UV-vis-NIR range (averaging 82.1%). These findings suggest that HSN can be utilized as an effective inorganic filler in the formulation of reflective and thermally insulating coatings.

Study of synergistic effects induced by novel base composites on heavy metals removal and pathogen inactivation

The green-collar strategies for nanomaterial synthesis with novel structural competencies have received significant attention in nanotechnology owing to their potential benefits. The utilization of silica nanoparticles for wastewater treatment through heavy metal ions remediation is the focal point of the present study. With this intent, silica was extracted from bagasse ash by the sol-gel method and modified using chitosan. Chemical and physical characteristics of silica(S), silica/Chitosan (SCs), were reckoned through X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) and the efficiency of synthesized biomaterials for removing heavy metal ions. Cadmium and Lead from wastewater was evaluated by conducting closed batch experiments. Isotherm and kinetics models were applied to understand the adsorption mechanism. Results of heavy metal ions removal showed that the S possesses the highest removal efficiency of 88% for cadmium. Equilibrium was established within 56 min following a Langmuir isotherm model and pseudo-second-order reaction. The synthesized biomaterials were also tested against the fungal (Aspergillus Niger) and bacterial strains (Escherichia coli and Staphylococcus aureus) to determine their antimicrobial properties Maximum inhibition of 26 mm was shown by SCs for E.coli. Synthesized samples were not so effective for A.niger. The high adsorption potential of silica nanoparticles reveals their potential to treat wastewater containing inorganic pollutants like calcium and lead released from the sugar industry firsthand, thereby building a circular economy by controlling the pollution from source to sink. The synthesized silica nanoparticles and silica/chitosan biomaterials demonstrated high adsorption potential for heavy metal ions, making them promising candidates for integration into Algal Membrane Bioreactors to enhance wastewater treatment efficiency and remove toxic pollutants. Their multifunctional properties, including antimicrobial activity, also offer potential for improving microbial control within AMBRs, ensuring a more effective and sustainable wastewater treatment process.