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SEM images of modified silica nanoparticles in different experimental conditions according to Table 1.
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In this work, silica nanoparticles (SNPs), vinyl and acrylate modified SNPs were synthesized by a novel one-pot synthesis method using TEOS and the appropriate organosilanes as the modifier molecules including vinyltrimethoxysilane (VTMS) and 3-(methacryloyloxy) propyltrimethoxysilane (MPS). Although, spherical SNPs with average diameter ranging fr...
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... second silane or the modifying si- lane, a practically important result was attained. The second silane molecule has a size decreasing effect on the average diameter of the final modified-SNPs. This will be discussed here in detail although, has also been observed in our previous works [9,11]. SEM images for VSE1; VSM1, VSE3 and ASE3 are given in Fig. 2 and the average di- ameters are summarized in Table 1. It can be seen that all the modified-SNPs have smaller diameters compared to their corre- sponding unmodified SNPs. For instance, SE1 has average diameter of 465 nm while, the corresponding vinyl modified silica, VSE1, is smaller with an average diameter of 423 nm. Accordingly, SE3 ...
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... Employing TEOS in conjunction with suitable modier molecules, such as vinyltrimethoxysilane (VTMS) and 3-(methacryloyloxy) propyltrimethoxysilane (MPS), E. Effati et al. successfully synthesized silica nanoparticles (SiNPs) with vinyl and acrylate modications. 22 Through the ne-tuning of reaction conditions, this process yielded spherical SiNPs with average diameters that spanned a range from 50 to 700 nm. Gholami et al. synthesized spherical SiNPs using a sonochemical technique by reacting TEOS, methanol, and ethylenediamine (en) in the presence of an organic Schiff base ligand (Salpn-NO 2 ) 23 using water as solvent. ...
Silica nanoparticles (SiNPs) have emerged as a multipurpose solution with wide-ranging applications in various industries such as medicine, agriculture, construction, cosmetics, and food production. In 1961, Stöber introduced a ground-breaking sol–gel method for synthesizing SiNPs, which carried a new era of exploration both in academia and industry, uncovering numerous possibilities for these simple yet multifaceted particles. Inspite of numerous reported literature with wide applicability, the synthesis of these nanoparticles with the desired size and functionalities poses considerable challenges. Over time, researchers have strived to optimize the synthetic route, particularly by developing greener approaches that minimize environmental impact. By reducing hazardous chemicals, energy consumption, and waste generation, these greener synthesis methods have become an important focus in the field. This review aims to provide a comprehensive analysis of the various synthetic approaches available for different types of SiNPs. Starting from the Stöber' method, we analyze other methods as well to synthesis different types of SiNPs including mesoporous, core–shell and functionalized nanoparticles. With increasing concerns with the chemical methods associated for environmental issues, we aim to assist readers in identifying suitable greener synthesis methods tailored to their specific requirements. By highlighting the advancements in reaction time optimization, waste reduction, and environmentally friendly precursors, we offer insights into the latest techniques that contribute to greener and more sustainable SiNPs synthesis. Additionally, we briefly discuss the diverse applications of SiNPs, demonstrating their relevance and potential impact in fields such as medicine, agriculture, and cosmetics. By emphasizing the greener synthesis methods and economical aspects, this review aims to inspire researchers and industry professionals to adopt environmentally conscious practices while harnessing the immense capabilities of SiNPs.
... 5 To overcome this challenge and introduce functionality, a core-shell particle can be obtained through the reaction of a functionalised siloxane, such as mercaptopropyltrimethoxysilane (MPTMS); however, this requires additional steps and can cause loss of control of the particle size and uniformity. [5][6][7][8] The direct formation of particles with reactive functionalities can be achieved using trifunctional siloxane precursors such as MPTMS; however, solubility is a major challenge. 5,[9][10][11] The Stöber process has better size control and can achieve smaller particle sizes than the alternative stabilised emulsion approach. ...
The homogeneous addition of functional silanes dissolved in a co-solvent such as ethanol has been shown to change particle growth mechanisms as well as control over particle size and dispersity, especially for non-polar silanes. Highly monodisperse size-controlled silica particles from 50 to over 1000 nm bearing thiol, vinyl, phenyl, propyl, cyanopropyl and chloropropyl R group functionality were synthesised directly from the corresponding single organosilane source. Observing particle growth over time revealed that it proceeded by a conventional Stöber process, where silane monomers and oligomers add to nucleation sites, resulting in particle growth. Scale-up of the homogeneous mixing approach produced gram quantities of particles without affecting size, size dispersion or functionality under good mixing. The presence and functionality of the surface R groups were confirmed by a simple second addition of reactive molecules to the particle synthesis liquor, resulting in theoretical maximum attachment densities.
... There was a reduction in the amount of adsorbent water on the surface and in its pores as a result of this remarkable degradation [48]. The dihydroxylation of silanol groups on an exterior surface of DE-AC is most likely to blame for the loss of the sulfonate group at temperatures ranging from 200 • C to 700 • C [49]. ...
Background: Currently, the rising demand for green chemistry and sustainable development encourages the creation and use of eco-friendly resources (industrial and agricultural wastes) for the production of high-value substants. In this study, solid-acid heterogenous catalysts derived by diatomaceous earth (DE), empty fruit branch (EFB), and montmorillonite (MMT) treated by sulfuric acid, phosphoric acid, and tungsten metal, respectively, were examined. Microwave-induced radiation was then used to improve both the DE and EFB surface. Methods: All modified catalysts were accordingly used to produce ethyl lactate by esterification. Characteristics of sulfonated diatomaceous earth (DE-AC), phosphorous treated empty fruit branch (EFB-AC), and tungsten-supported montmorillonite (W/MMT) were analyzed using FTIR, XPS, NH3-TPD, XRD, SEM-EDX, BET, and TGA in order to examine their physical and chemical characteristics. Significant findings: The DE-AC and W/MMT showed a high potential for usage as solid acid catalysts, containing 2981 and 1298 µmol/g of the total acid site, respectively. The yields of ethyl lactate for DE-AC, W/MMT, and EFB-AC were 58.55, 47.56, and 32.75%, respectively. Furthermore, DE-AC and W/MMT exhibit outstanding reusability for five consecutive cycles, indicating their potential as solid catalysts for ethyl lactate synthesis.
... Scheme 1A and B provide synthesis routes of comblike SiO 2 NPs-V-PDMA. Firstly, VTMS moieties were modified onto the agglomerated SiO 2 NPs through dehydration of a water (H 2 O) molecule by an NH 3 catalyst [17,[52][53][54]. To impart the superhydrophobic properties, the DMA was grafted onto the SiO 2 NPs-V surface through free radical reaction using simultaneous EB-induced graft polymerization technique. ...
... The SiO 2 NPs slowly decomposed with a weight loss of around 5% due to absorbed moisture and its ash residue still remained as high as 95% within the temperature range of 50 to 800 • C ( Fig. 1F(a)). Weight losses of the SiO 2 NPs and the modified SiO 2 NPs-V were identified on the basis of TGA curve analysis and comparison with relevant data reported in the literatures [52,[77][78][79]. When VTMS was modified onto SiO 2 NPs, the degradation temperature (T d ) of VTMS compound was found at 511 • C. A new decomposition temperature range confirms that VTMS was successfully introduced onto SiO 2 NPs. ...
The current research focuses on tailoring silica nanoparticles (SiO2NPs) with comb-like poly(dodecyl methacrylate) (PDMA) brushes and tuning coating parameters based on roller coating process for confining surface morphology towards hydrophobic and superhydrophobic including water-repellent surface. Electron beam (EB) induced a simultaneous “graft-from” polymerization of DMA monomer onto vinyl modified SiO2NPs (SiO2NPs-V) was established in an inventive castor oil/ethanol mixed solvent. Functional surface chemistry of SiO2NPs and nanorough surface topography controlled by NPs content and coating thickness mainly influences the hydrophobic/superhydrophobic, water-repellent, and water absorption properties including gloss values, whiteness and yellowness index of coated papers. The papers coated with SiO2NPs-V-PDMA/PVA of 6–10 wt% with the thickness of ~10–14 μm exhibited matt surface and provided superhydrophobic and water-repellent properties. The coated paper has a desirable and stable water contact angle of 152°, low droplet adhesion with lower dynamic tilting angle (<5°), and 5.3-folds reduced water absorption. Our investigation provides compelling evidence that the SiO2NPs-V-PDMA obtained from EB modification and the developed coating formula for roller-based coating process are realistic approaches for hydrophobic/superhydrophobic coatings and printing inks for paper-based industries.
... It is noteworthy that this significant degradation indicated the elimination of the adsorbed water on the surface and into the pores of the DE (Reka et al., 2017). The loss of sulfonate group at temperature range between 200 • C and 700 • C, is most likely due to dihydroxylation of silanol groups on the external surface of DE (Effati and Pourabbas, 2012). ...
In this study, solid acid catalysts were prepared from different sources including oil palm kernel shell, corncob, and diatomaceous earth. Then, the raw materials were sulfonated and further activated by a microwave-induced reactor. Characteristics of sulfonated oil palm kernel shell (OPS-AC), corncob (CK-AC), and diatomaceous earth (DE-AC) were analysed using FTIR, XPS, NH3-TPD, XRD, SEM, BET, and TGA to establish their physical and chemical properties. The CK-AC and DE-AC showed high potential to be used as solid acid catalysts consisting of the strong acid site (-SO3H and -COOH) with 2344 and 3098 μmol/g for CK-AC and DE-AC, respectively. The DE-AC exhibited better thermal stability by only 7% of mass loss observed. The ester yields of 54.2 and 60.4% were achieved over CK-AC and DE-AC, respectively. Moreover, DE-AC shows the outstanding reusability for five successive times, which is promising as the potential solid catalysts for ethyl propanoate production.
... For this purpose, the possibility of immobilization of silica nanoparticles (Si NPs) on the membrane surface was studied. Hydrophobization of PET TeMs by immobilization of silica nanoparticles is shown in Figure 7. First of all, Si NPs with C=C bonds were synthesized from TEVS by the sol-gel method [183]. The resulting solution of silica nanoparticles in ethanol was subsequently used to modify PET ion-track membranes. ...
... For this purpose, the possibility of immobilization of silica nanoparticles (Si NPs) on the membrane surface was studied. Hydrophobization of PET TeMs by immobilization of silica nanoparticles Polymers 2021, 13, 2520 16 of 28 is shown in Figure 7. First of all, Si NPs with C=C bonds were synthesized from TEVS by the sol-gel method [183]. The resulting solution of silica nanoparticles in ethanol was subsequently used to modify PET ion-track membranes. ...
Membrane distillation (MD) is a rapidly developing field of research and finds applications in desalination of water, purification from nonvolatile substances, and concentration of various solutions. This review presents data from recent studies on the MD process, MD configuration, the type of membranes and membrane hydrophobization. Particular importance has been placed on the methods of hydrophobization and the use of track-etched membranes (TeMs) in the MD process. Hydrophobic TeMs based on poly(ethylene terephthalate) (PET), poly(vinylidene fluoride) (PVDF) and polycarbonate (PC) have been applied in the purification of water from salts and pesticides, as well as in the concentration of low-level liquid radioactive waste (LLLRW). Such membranes are characterized by a narrow pore size distribution, precise values of the number of pores per unit area and narrow thickness. These properties of membranes allow them to be used for more accurate water purification and as model membranes used to test theoretical models (for instance LEP prediction).
... The synthesis of Si NPs with C=C bonds was based on the sol-gel method described in [56]. To reduce the average NPs size, the addition of surfactants was investigated. ...
... The synthesis of Si NPs was based on the procedure described in the work [56]. To reduce NPs size, surfactant was used. ...
The paper describes desalination by membrane distillation (MD) using ion-track membranes. Poly(ethylene terephthalate) (PET) ion-track membranes were hydrophobized by the immobilization of hydrophobic vinyl-silica nanoparticles (Si NPs). Si NPs were synthesized by the sol-gel method, and the addition of the surfactant led to the formation of NPs with average size of 40 nm. The thermal initiator fixed to the surface of membranes allowed attachment of triethoxyvinyl silane Si NPs at the membrane surface. To further increase hydrophobicity, ethoxy groups were fluorinated. The morphology and chemical structure of prepared membranes were characterized by SEM, FTIR, XPS spectroscopy, and a gas permeability test. Hydrophobic properties were evaluated by contact angle (CA) and liquid entry pressure (LEP) measurements. Membranes with CA 125–143° were tested in direct contact membrane distillation (DCMD) of 30 g/L saline solution. Membranes showed water fluxes from 2.2 to 15.4 kg/(m2·h) with salt rejection values of 93–99%.
... In the co-condensation method, the functionalized MSNs can be obtained through adding the silane precursor bearing the desired functional group to the batch of synthesis reaction composition including the silica precursor, organic template, and others. The direct co-condensation approach merges multiple steps of synthesis and functionalization and helps to efficiently control the site selective distribution of the organic groups (Kecht et al. 2008;Morelli et al. 2011;Effati and Pourabbas 2012;Khosraviyan et al. 2016). ...
... Kecht et al. (2008) summarized the role of selective functionalization of the outer surface of silica nanoparticles for many applications: (i) it determines colloidal stability and interaction with the surrounding environment, (ii) it does not influence the diffusion of the guest molecules into the mesopores, and (iii) it allows attachment of large molecular moieties keeping the internal textural properties intact. Nevertheless, exclusive site selective surface functionalization of different types of MSNs remains as a challenge for researchers over the years (Kecht et al. 2008;Morelli et al. 2011;Effati and Pourabbas 2012;Khosraviyan et al. 2016). In some drug delivery applications using MSNs as reservoir, selective modification of the external surface with optimal textural properties of the nanoparticles is required to fully access the inner pore wall of the as-synthesized material for guest molecule loading (Morelli et al. 2011;Wei et al. 2012;Jin et al. 2017). ...
In this study, a suitable route for the selective functionalization of the outer surface of MCM-48-type mesoporous silica nanoparticles (MSNs) and its impact on the physicochemical properties were investigated. The synthesis of MCM-48 nanoparticles with intact cubic ordered mesopore structure and functionalized outer particle surface was managed by postsynthetic and co-condensation modification routes with 3-methacryloxypropyltrimethoxy-silane (MPS). The results of FTIR, 29Si and 13C NMR, thermogravimetric, and elemental analysis confirmed the successful silane surface grafting by both methods. The nitrogen sorption analysis showed the selective outer surface functionalization by the postsynthetic route for the synthesized MCM-48 nanoparticles containing the template still inside the pore channels and in the case of the co-condensation route via late addition of the silane precursors into the synthesis batch containing a fully grown silica. The solvent type in the former approach and silane addition time during the particle growth in the later route showed a significant impact on the silane content and site selective binding. The amount of grafted silane was determined by thermogravimetric and elemental analysis. It was found to increase using toluene in the postsynthetic modification route. The average particle size measured from SEM/TEM analysis ranges from 290 to 350 nm. The cubic ordered pore structure of the final silane grafted MSNs was fully preserved in both functionalization routes as corroborated from XRD analysis. In conclusion, MCM-48 nanoparticles selectively functionalized on the outer particle surface are favorable candidates for the subsequent site selective grafting reactions.
... challenge. Moreover, the "one-pot" method seems like the simplest way for the synthesis of hybrid silica nanoparticles [36,37], which can be used as a carrier of nonpolar components. ...
The design of cargo carriers with high biocompatibility, unique morphological characteristics, and capability of strong bonding of fluorescent dye is highly important for the development of a platform for smart imaging and diagnostics. In this paper, BODIPY-doped silica nanoparticles were prepared through a “one-pot” soft-template method using a sol-gel process. Several sol-gel precursors have been used in sol-gel synthesis in the presence of soft-template to obtain the silica-based materials with the most appropriate morphological features for the immobilization of BODIPY molecules. Obtained silica particles have been shown to be non-cytotoxic and can be effectively internalized into the cervical cancer cell line (HeLa). The described method of synthesis allows us to obtain silica-based carriers with an immobilized fluorescent dye that provide the possibility for real-time imaging and detection of these carriers.
... The use of growth inhibitor additives and functional organosilanes (Kim et al. 2005;Möller et al. 2007;Urata et al. 2009;Zhang et al. 2011;Effati and Pourabbas 2012) improves the particle dispersity and helps to control the particle size of MSNs. Therefore, the complexing agents TEA and Pluronic® F127 were used as additives to achieve a fine dispersion and to efficiently control the particle size. ...
Monodispersed spherical silica nanoparticles with a cubic mesostructure were synthesized in a fast and innovative way using triethanolamine (TEA) and the triblock copolymer Pluronic® F127 as particle growth inhibitors to control the particle size in a range from 420 to 62 nm. In this study, we described a synthesis of mesoporous silica nanoparticles (MSNs) with MCM-48 structure at room temperature with adequate control of particle monodispersity, shape, and size using TEA. Based on particle characterization, TEA can efficiently act as catalyst and at the same time as particle growth controlling additive. A mixture of TEA and Pluronic® F127 additives was used to obtain very small MSNs (62 nm), whereby the quality of MCM-48 silica is associated with the composition of the additives used and thus also with the final particle size. A finely dispersed and high-quality MCM-48 material with ~ 100% yield, excellent textural properties, and a particle size of 295 nm was synthesized within only 35 min using excess TEA as particle size controlling and dispersion agent together with ammonia as additional catalyst. Solvent extraction combined with ion exchange removed the surfactant efficiently. All prepared MSNs showed good textural properties, tunable particle sizes with narrow size distributions, and good dispersity in water, which make them highly promising as carriers for biomolecules in biomedical applications.
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