Characterization Of Silica Nanoparticles Research Articles

Fabrication and Characterization of Silica Nanoparticles from Beach Sand

Silica nanoparticles (SNPs) have many important applications including anti-reflection coating, self-cleaning surface and drug carriers. They are usually synthesized from the commercial precursor such as tetraethyl orthosilicate (TEOS). On the other hand, the natural silica can be found abundantly in organic materials such as rice husk and palm shell or in inorganic material such as beach sand and clay. Therefore, obtaining SNPs from the natural resources is very strategic for economic and technology considerations. This motivates the current study performing the synthesis and characterization of SNPs derived from the beach sand as one of natural resources available. Fort this purpose, the silica sands were mixed with sodium hydroxide (NaOH) for 2 hours at 90⁰ C, prior to filtering process for gaining the sodium silicate solution (SSS) which was further refluxed with hydrochloric acid (HCl) of 3 and 5 M until its pH reached the value of 7, and finally dried. The characterizations carried out on the resulting SNPs included UV-Vis and FTIR spectroscopies, XRD and SEM. The XRD study confirmed that the resulting samples are amorphous silica phase with the average crystallite size of 4.8 and 2.9 nm for the SNPs synthesized with 3 and 5 M chloric acid, respectively. The image analysis of SEM results revealed that the obtained SNPs have the average diameter of 11.6-12.00 nm. The formation of SNPs was further confirmed with the UV-Vis and FTIR spectroscopies. On the basis of investigation results, it was shown that the desired silica nanoparticles can be successfully derived from the beach sand.

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.

Preparation and characterization of silica nanoparticles using beach sand and their anti-viral activity against white spot syndrome virus (WSSV): in vitro and in silico studies

Preparation and characterization of silica nanoparticles using beach sand and their anti-viral activity against white spot syndrome virus (WSSV): in vitro and in silico studies

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.

Process for recovery and value addition of silica mineral values of distinctly siliceous mining rejects

The mining and metal industries generate a variety of solid wastes from mining activities to finished products. Mining rejects of non-ferrous industries such as bauxite, manganese, gold, zinc, lead and copper mines are underutilized and low in demand as potential raw materials for metallurgical use. Largely these materials are in bulk use for landfilling and building materials without recovering relevant mineral values. Major reject materials such as jarosite, kaolinite, khondalite, alumogoethite and saprolite are rich sources of alumina and silica-bearing mineral phases with varying compositions of iron oxide as major constituents. In the present study, the chemical and mineralogy of some of these materials were assessed. The technical scope for recovering one of the low-cost mineral phases in the rejects such as silica was ascertained for the potential value addition in view of the large scope of utilization in glass, glass products, molten sand, cement, fibreglass, ceramic enamel, sandblasting, refractory and light concrete.The recovered silica was used as a low-cost precursor for making value-added nano-silicate suitable for various industrial applications. The paper discussed the significance of the chemical composition and mineralogy of the raw materials. The process steps involved in the selective beneficiation of silicate mineral phases are used for the stepwise removal of iron oxide and alumina followed by the preparation of sodium silicate. Chemical precipitation and separation of nano-silica followed by characterization of silica nano-particles by scanning electron microscopy (SEM) and inductively coupled plasma (ICP)-MS analysis was also elaborated. These SEM studies inferred that the silica particles size ranges from nanometer to micrometre depending on various factors such as acid concentration, ageing time and the nature of the precursor used. ICP-MS analysis revealed the purity of nano-silicate prepared from the reject material. The leached solution consisting of aluminium has been utilized for making alpha alumina based on the IPR-protected in-house process route to follow the concept of producing zero waste.

Preparation and characterization of silica nanoparticles (sol–gel & river sand): A comparative toxicity studies against seed weevil (Sitophilus oryzae L). and effect on agro-morphological characteristics of maize seeds

The present study aimed to compare the entomotoxic efficacy of silica nanoparticles obtained through sol–gel and river sand against Sitophilus oryzae L. by keeping insecticidal dust (malathion 5D) as a control. Physicochemical characterization results revealed that silica nanoparticles (SiO2 NPs) were spherical in shape. Bioassay studies exhibited the LD50 values as 0.44 mg/100 g for sol–gel synthesized SiO2 NPs and 0.92 mg/100 g for river sand based SiO2 NPs. Cent percent mortality was brought about by sol–gel synthesized SiO2 NPs at the dose of 3 mg after 4 days of exposure whereas only 73.33 ± 1.57 per cent mortality was observed for river sand based SiO2 NPs at the dose of 9 mg after 4 days. Further, sol–gel synthesized SiO2 NPs [LD90 (6.64 mg/100 g maize seed)] enhanced the seedling characteristics i.e., (%) germination (98 ± 1.72), seedling length (49.71 ± 0.13 cm), vigour index (4871.58) and dry matter production (4.00 ± 0.01 g) compared to river sand based SiO2 NPs.

Preparation and characterization of silica nanoparticles as an efficient carrier for two bio‐detergents based enzymes

AbstractBio‐detergents are new bio‐friendly formulas that contain biobased ingredients, including enzymes. In the present study, alkaline protease and α‐amylase were immobilized via physisorption onto silica nanoparticles (SNPs). The derivatized SNPs served as major components of a prepared bio‐detergent. Alkaline protease was produced by the recombinant Bacillus subtilis cells that carry the protease genes on a multiple‐copy plasmid, while α‐amylase was commercially purchased. SNPs were prepared by the sol–gel method and well‐characterized through the Brunauer–Emmett–Teller (BET) method, scanning electron microscopy (SEM), transmission electron microscopy (TEM), zeta potential, X‐ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The adsorption capacity of the SNPs was determined via colorimetry through the adsorption of methylene blue dye (MB), with approximately 97% adsorption achieved under the conditions employed. The Langmuir isotherm well‐described the adsorption of MB on SNPs. High immobilization yield for the enzymes was obtained, and the storage stability of SNP‐alkaline protease and SNP‐α‐amylase was good, reaching 65% and 85% of their initial activities after 6 weeks of storage at 4°C, respectively. The immobilized enzymes could be reused for 7 cycles. Additionally, the immobilized enzymes retained residual activity to a greater extent than free enzymes in simulated basic detergent solutions. SNPs containing adsorbed alkaline protease and α‐amylase were mixed with a basic detergent solution, and the washing efficiency of some proteinous and starchy stains was examined through Hunter Lab spectrophotometry. The latter experiments demonstrated that the immobilized enzymes performed well during the washing process.

Synthesis and characterization of silica nanoparticles from rice ashes coated with chitosan/cancer cell membrane for hepatocellular cancer treatment

Dual pH-sensitive smart nanocarriers based on silica nanoparticles (SNPs) extracted from rice husk ashes (RHAs) to effectively inhibit liver cancer cell proliferation were investigated. The SNPs were coated with chitosan (CH) and loaded with doxorubicin (DOX), then functionalized with cell membrane (CM) for homologous targeting ability. The FTIR spectra showed an absorption wave number at 1083 cm−1 which confirmed the existence of the SiOSi group, ratifying that the nanocarriers belong to silica species. The Korsmeyer-Peppas kinetic model reported R2 values of 0.996 and 0.931 for pH = 5.4 and pH = 7.4, respectively, demonstrating pH-responsive behavior of the nanocarriers. The cytotoxicity test confirmed that the HepG2 cell line treated with different SNP–CH–CM concentrations had no detectable significant cell toxicity, however, SNP–CH–DOX–CM induced greater cell death. In vivo tests revealed that SNP–CH–DOX–CM suppressed liver cancer growth in nude mice, demonstrating high pharmaceutical capability. Histological examination of vital organs showed that the targeted drug delivery system (DDS) had minor in vivo toxicity. In the light of its high treatment efficacy and minimal side effects, the investigated DDS is promising for the therapy of liver cancer.

Facile Preparation and Characterization of Silica Nanoparticles from South Africa Fly Ash Using a Sol–Gel Hydrothermal Method

Silica nanoparticles (SNPs) consist of several applications which include lightweight aggregates, energy storage, and drug delivery. Nevertheless, the silica reagents used in SNP synthesis are both costly and hazardous. As a result, it is critical to look for other sources of silica. For this research, a simple sol–gel hydrothermal approach is used to make SNPs from South African fly ash (SAFA). SAFA is classified as fly ash class F according to X-ray fluorescence (XRF) analysis. The wide-angle X-ray diffraction (XRD) pattern reveals the structural composition of SAFA and the amorphous phase of extracted SNPs, while Fourier transform infrared (FTIR) examination reveals the presence of silanol and siloxane groups. Basic SNPs were generally spherical with diameters of about 60 nm, according to scanning electron microscopy (SEM) and transition electron microscope (TEM) studies. The presence of SiO2 is confirmed by energy-dispersive X-ray spectroscopy (EDX) spectrum analysis. Particle size assessment indicates particle sizes ranging from 48 nm to 87 nm in diameter, with a mean diameter of 67 nm. The application of SNPs in wastewater treatment demonstrated that they can be used to remove Cd2+ from an aqueous solution. This research offers new ideas for using South African fly ash in SNP manufacturing.

Synthesis and characterization of silica nanoparticles from rice husk and their effects on physiology of rice under salt stress

Silicon (Si) is considered a beneficial element for rice (Oryza sativa L.) The objective of this work was to investigate the effects of Si in the form of nanoparticles on growth and physiology of rice under salt stress. Silica nanoparticles (SNPs) were synthesized from rice husk by sol-gel method. The prepared SNPs powders were agglomerated in semi-spherical nano- sized particles with diameters in the range of 60-135 nm. Three rice cultivars namely ‘Pokkali’, ‘KDML105’ and ‘IR29’ were grown for 30 d in plastic pots, and then divided into four groups i.e., control, SNPs, NaCl and NaCl + SNPs. Foliar spray of 120 mg L-1 SNPs was given to the SNPs and NaCl + SNPs groups for 4 d. After that the plants in NaCl and NaCl + SNPs groups were exposed to 150 mM NaCl for 17 d. The salt-stressed plants suffered significant reductions in biomass, net photosynthesis rate (PN), and maximal quantum efficiency of photosystem II (PSII) photochemistry (Fv/Fm) while three stress indicators (malondialdehyde, hydrogen peroxide [H2O2] and proline) considerably increased. The SNPs mitigated the adverse effects of salt stress by increasing PN (18% to 116% increase) and lowering H2O2 (8% to 31% reduction) in all cultivars, compared with the values under salt stress, while proline was reduced by 7% in ‘KDML105’ and 19% in ‘IR29’. The H2O2 content was regulated by the increased activities of antioxidant enzymes, notably catalase, peroxidase and ascorbate peroxidase. The application method and concentrations of SNPs used for rice plants under stress should be further optimized for the highest benefit of growth and yield in the field conditions.

A Single-Step Digestion for the Quantification and Characterization of Trace Particulate Silica Content in Biological Matrices Using Single Particle Inductively Coupled Plasma-Mass Spectrometry.

The increased use of amorphous silica nanoparticles (SiNPs) in food products, materials science, cosmetics, and pharmaceuticals has raised questions about potential hazards in the environment and in human health. Although SiNPs are generally thought to be benign, recent studies have demonstrated toxicity in different cell and animal models. Despite their ubiquitous use, SiNPs are rarely analyzed quantitatively. Often, the methods used to analyze silicon and SiNPs are difficult, costly, require the use of dangerous reagents, and are prone to interferences. Additionally, characterization of SiNPs in complex matrices requires extensive sample preparation. To address this, we propose a single-step digestion method for the determination of trace SiNP content in biological matrices. For conventional inductively coupled plasma-mass spectrometry (ICP-MS) analysis, biological samples are often digested with concentrated HNO3. We found that with conventional ICP-MS, lower limits of detection (LLOD) of silicon are too high for trace analysis. However, we found that SiNPs are stable at a strong acidic pH; thus, concentrated HNO3 could be used to digest biological samples leaving SiNPs intact. Then, by analysis with single particle ICP-MS, we found that the smallest SiNP that could be read was 185nm in size. The concentration for the LLOD was found to be 0.032ppb with interday variability in sizing and concentration at 2.5% and 6.8% respectively. Utilizing this method, SiNPs were accurately sized and counted in cell pellets and media. Our proposed method can be used to accurately quantify and characterize SiNPs (or agglomerated SiNPs) larger than the derived LLOD in a variety of biological matrices and will assist in determining relationships between exposures of SiNPs and toxicity in humans and the environment.

Characterization of Silica Nanoparticles and Nanocolloid Synthesized in Acidic and Alkaline Media

Nanosilica in known as one of the most widely used components in various industries. In the current study, silica nanoparticle/colloid were synthesized in acidic and alkaline media using sodium silicate as a precursor. The effect of synthesis parameters on the morphology of the obtained nanoparticles and the rheological properties of silica colloid were studied. Microscopic observations revealed that size and morphology of the obtained silica nanoparticles can be changed by varying the ammonia to ethanol ratio, as well as the concentration of sodium silicate solution. The results revealed that the particles size is raised by increasing the ethanol to ammonia ratio and increasing the sodium silicate concentration leads to irregular and larger particles. the particles In fact, at (EtOH/NH3 :1 and Na2SiO3/H2O:0.07) a stable colloidal silica containing silica nanoparticles with average diameter of 65nm could be achieved. Additionaly, gelation time (tgel) of nanocolloid was measured using time sweep at constant frequencies of 0.1, 0.3 and 0.5 Hz. Applying the gelation point relations, the relaxation power (Δ) and fractal dimension (df) were measured as 0.22 and 2.39, respectively, indicating that the current system follows a non-stoichiometric equilibrium. Furthermore, the Fourier transform infrared spectroscopy (FTIR) test confirmed the formation of silica chemical bonding and the purity of the washed silica particles was increased from 84.18% to 87.33%, measured via X-ray fluorescence spectroscopy (XRF)

Preparation and Characterization of Silica Nanoparticles and of Silica-Gentamicin Nanostructured Solution Obtained by Microwave-Assisted Synthesis.

In this research work, silica nanoparticles and silica-gentamicin nanostructured solution were synthesized by using the microwave-assisted synthesis, in basic medium, using two silane precursors (tetraethylorthosilicate and octyltriethoxysilane) and the antibiotic (gentamicin sulfate). The prepared materials were characterized through Fourier transform infrared (FTIR) spectroscopy, TGA analysis, transmission electron microscopy (TEM), and atomic force microscopy (AFM) to investigate the morphology and structure. Antimicrobial studies of the silica-gentamicin nanostructured solution versus silica nanoparticles were performed against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. FTIR spectra showed that the gentamicin has been loaded to the silica nanoparticles. AFM analysis showed that the morphology of the silica-gentamicin nanostructured solution has changed, and agglomerations of particles are present at the surface. Antimicrobial testing, performed using the diffusion method through spot inoculation, indicates that the silica-gentamicin nanostructured solution exhibited activity against the resistant strain. The obtained silica-gentamicin solution can be used as biochemical agent for the prevention and treatment of microorganisms which are deposited on different surfaces (e.g., glass, plastic, ceramic).

Facile Extraction and Characterization of Silica Nanoparticles from Corn Stalk by Sol-Gel Hydrothermal Methods

Lightweight aggregates, drug delivery and energy storage are some of the numerous applications of silica nanoparticles. Amorphous silica was extracted from corn stalk using the sol-gel hydrothermal method and nanostructured using Hexadecyl trimethyly ammonium bromide (CTAB) as template. The crystallographic structures of synthesized silica nanoparticles was characterized using X-Ray Diffraction (XRD). Functional groups was determine using fourier transform infrared (FT-IR) techniques, specific surface area was determine using the Brunauer Emmett Teller (BET) method. The presence of SiO2 was confirmed by Energy dispersive X-ray (EDX), surface morphology and particle size was examine using scanning electron microscope (SEM) and transition electron microscope (TEM). This study provide a silica nanoparticles sourced from agricultural biomass for cutting-edge applications including drug delivery.

Sol-Gel Auto-Combustion Preparation and Characterization of Silica Nanoparticles for The Removal of Congo Red Dye from Aqueous Media

Sol-Gel Auto-Combustion Preparation and Characterization of Silica Nanoparticles for The Removal of Congo Red Dye from Aqueous Media

Production and characterization of silica nanoparticles from fly ash: conversion of agro-waste into resource

A chemical method to synthesize amorphous silica nanoparticles from the incinerated paddy straw has been introduced. The synthesis was conducted through the hydrolysis by alkaline-acidic treatments. As a result, silica particles produced with the sizes were ranging at 60–90 nm, determined by high-resolution microscopy. The crystallinity was confirmed by surface area electron diffraction. Apart from that, chemical and diffraction analyses for both rice straw ash and synthesized silica nanoparticles were conducted by X-ray diffraction and Fourier-transform infrared spectroscopy. The percentage of silica from the incinerated straw was calculated to be 28.3. The prominent surface chemical bonding on the generated silica nanoparticles was with Si–O–Si, stretch of Si–O and symmetric Si–O bonds at peaks of 1090, 471, and 780 cm−1, respectively. To confirm the impurities of the elements in the produced silica, were analyzed using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The stability of silica nanoparticles was investigated using thermogravimetric analysis and zeta potential. The measured size from zeta potential analysis was 411.3–493 nm and the stability of mass reduction was located at 200 °C with final amount of mass reduced ∼88% and an average polydispersity Index was 0.195–0.224.

Green technology extraction and characterisation of silica nanoparticles from palm kernel shell ash via sol–gel

Silica nanoparticles have numerous applications including drug delivery, lightweight aggregates, and energy storage. It has been manufactured from different agricultural bioresources with limited research on palm kernel shell ash (PKSA). This study produced silica nanoparticles from palm kernel shell ash. Modified sol–gel extraction technique was used to produce the silica nanoparticles from PKSA. The extracted silica nanoparticles were characterized using X-ray diffraction (XRD), Scanning electron microscope (SEM) with Energy dispersive X-ray (EDX), Fourier transform infrared (FT-IR) techniques, Brunauer–Emmett–Teller (BET) method and Thermogravimetric analysis (TG). The microstructural analysis reveals that the unit size of the extracted silica nanoparticles is between 50–98nm, with a very high specific surface area (438m2g−1). EDX confirmed the presence of SiO2 in the sample. FT-IR analysis shows the existence of silanol and siloxane groups. This success means, decrease in environmental contamination caused by indiscriminate disposal of palm kernel shell (PKS) and silica nanoparticles for advanced material applications.

RhB-encapsulating silica nanoparticles modified with PEG impact the vascular endothelial function in endothelial cells and zebrafish model

Silica nanoparticles (SiNPs) have been widely used in human health related products, such as food additives, cosmetics and even drug delivery, gene therapy or bioimaging. Recently, a first-in-human clinical trial based on polyethylene glycol (PEG)-modified SiNPs had been approved by US FDA to trace melanoma. However, as a nano-based drug delivery system, its biocompatibility and vascular toxicity are still largely unknown. Thus, we synthesized the fluorescent SiNPs to explore the biocompatibility and vascular endothelial function, and compare different biological effects caused by PEG-modified and unmodified SiNPs in cells and zebrafish model. The characterizations of SiNPs and PEG-modified SiNPs were analyzed by TEM, SEM, AFM and DLS, which exhibited relatively good stable and dispersive. Compared with SiNPs, PEG-modified SiNPs had markedly reduced the inflammatory response and vascular damage in Tg (fli-1: EGFP) and Tg (mpo: GFP) transgenic zebrafish lines, respectively. Consistent with the in vivo results, the PEG-modified SiNPs had been found to significantly decline the levels of ROS, inflammatory cytokines and mitochondrial-mediated apoptosis in vascular endothelial cells compared to SiNPs, and the ROS scavenger NAC could effectively alleviate the above adverse effects induced by nanoparticles. Our results suggested that the PEG-modified SiNPs could become more safety via increasing the biocompatibility and decreasing cellular toxicities in living organisms.

Preparation and characterization of silica nanoparticles from sugarcane bagasse ash for using as a filler in natural rubber composites

Silica nanoparticles from sugarcane bagasse ash (SBA) were prepared from sol–gel process. Particle size, specific surface area, morphology, chemical composition and chemical structure of SBA and prepared silica nanoparticles were characterized. The effect of drying techniques such as freeze drying (FD) and heat drying (HD) on the properties of silica nanoparticles was investigated. High purity of silica nanoparticles in size range of 90 ± 10 nm were successfully prepared. FD provided silica nanoparticles with high specific surface area and high porosity compared to conventional HD. The effect of silica nanoparticle contents on cure characteristics, mechanical properties, and morphology of natural rubber (NR) composites was studied. Scorch time of NR composites was increased with an increase in silica nanoparticle content due to the disturbance of vulcanization process by silica surface. FD-silica/NR composites provided longer scorch time and cure time compared to HD-silica/NR composites due to higher active surface area of FD-silica. Modulus and hardness of NR composites were increased while elongation at break was decreased with an increase in silica nanoparticle content. Tensile strength of the composites increased with silica nanoparticle content and tended to reduce at high silica nanoparticle content. FD-silica/NR composites exhibited better mechanical properties than HD-silica/NR composites due to better filler-rubber interaction.

The chronic effect of amorphous silica nanoparticles and benzo[a]pyrene co-exposure at low dose in human bronchial epithelial BEAS-2B cells.

As the main components of fine particulate matter (PM2.5), silica nanoparticles (SiNPs) and benzo[a]pyrene (B[a]P) have attracted increasing attention recently. However, co-exposure to SiNPs and B[a]P causes pulmonary injury by aggravating toxicity via an unknown mechanism. This study aimed at investigating the toxicity caused due to long-term co-exposure to SiNPs and B[a]P on pulmonary systems at low dose using human bronchial epithelial (BEAS-2B) cells. The characterizations of SiNPs and B[a]P were done by transmission electron microscopy (TEM) and zeta potential granulometry. Cytotoxicity is evaluated using cell counting kit-8 (CCK-8) assay and lactate dehydrogenase (LDH) activity; oxidative stress, cell cycle and apoptosis were assessed by flow cytometry, and inflammatory factors were detected using a Luminex xMAP system. Results show an obvious inhibition of cell proliferation and a marked increase in the LDH expression in the BEAS-2B cells after long-term co-exposure. Furthermore, long-term co-exposure is the most potent in generating intracellular ROS, thus causing inflammation. Cellular apoptotic rate is enhanced in the co-exposed group at low dose. Moreover, the long-term co-exposure induces significant cell cycle arrest, increasing the proportion of cells at the G2/M phase, while decreasing those at the G0/G1 phase. This study is the first attempt to reveal the severe synergistic and additive toxic effects induced by SiNPs and B[a]P co-exposure for long-term in BEAS-2B cells even at low dose.