Synthesis Of Mesoporous Silica Research Articles

Synthesis of Mesoporous Silica from Palm Oil Boiler Ash (MS-POBA) with Addition of Methyl Ester Sulfonate as a Template for Free Fatty Acid Adsorption from Crude Palm Oil (CPO)

The synthesis of mesoporous material by utilizing palm oil boiler ash (POBA) waste as the silica source and methyl ester sulfonate (MES) surfactant as the template for a high-porosity was investigated for free fatty acids (FFA) adsorption. The research was initiated with silica extraction from POBA by sodium hydroxide addition through the sol-gel precipitation method. Silica modification was carried out with MES surfactant and 3-aminopropyltrimethoxysilane (APTMS) as the co-structure-directing agent (CSDA) in different calcination temperatures. Mesoporous silica-POBA (MS-POBA) free template had a surface area, pore diameter, and pore volume (41.033 m2/g, 4.180 nm, and 0.250 cm3/g) lower than MS-POBA with the template (71.0147 m2/g, 7.923 nm, and 0.524 cm3/g). The ability of MS-POBA to adsorb FFA reached its optimum conditions with an adsorption time of 20 min and an adsorbent dosage of 0.24 g. The FFA removal by MS-POBA with the template was found to have higher adsorption ability, which was 35.54%, compared to the MS-POBA free template of 26.68%. The high porosity of MS-POBA with a template makes the FFA adsorption capacity of this material higher than MS-POBA free template.

Synthesis and characterization of mesoporous silicas with dendritic and spongy-like structures: Potential supports for human lactate dehydrogenase-based microreactors aimed at anticancer inhibitor screening

Mesoporous silica are versatile materials with wide-ranging potential. Notably, they excel as enzyme supports. This work examines the influence of three distinct siliceous mesoporous materials used as supports for the enzyme human lactate dehydrogenase (hLDH-A). Drugs with inhibition effects have recently shown favorable effects on diminishing the proliferation of cancerous cells. The ultimate goal of this research is to produce a stable and effective biocatalyst suitable for being employed in a microreactor for the screening of hLDH-A inhibitors. The synthesized mesoporous silica exhibited distinctive structural features, including a quasi-mesocellular network, bent-channels structure, and a dendritic geometry with radial symmetry, as evidenced by FESEM and HR-TEM. These materials were functionalized with amino and aldehyde groups to covalently immobilize hLDH-A. Characterization of both pristine and functionalized materials involved a comprehensive examination of their physico-chemical properties. The CO dosing revealed Brønsted acidity characteristic of mesoporous silica, while FT-IR spectroscopy and N2 physisorption at 77 K confirmed their successful functionalization. Enzyme immobilization on the functionalized supports, performed with stabilizing agents such as PEG (0.05 mg mL−1) or trehalose (300 mM), produced promising results. The immobilization yield consistently exceeded 80 %, with retained activity reaching values as high as 15 %. The immobilization of the enzyme on mesoporous silica increased the stability of hLDH-A against alkaline and organic solutions. These findings hold significance for those exploring siliceous porous supports for enzyme immobilization, paving the way for the development of stable and active biocatalysts.

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

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

Photooxidation of organic compounds by mesoporous silica functionalized with rose bengal

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

Synthesis of Mesoporous Silica from Sugarcane Bagasse as Adsorbent for Colorants Using Cationic and Non-Ionic Surfactants

Synthesis of Mesoporous Silica from Sugarcane Bagasse as Adsorbent for Colorants Using Cationic and Non-Ionic Surfactants

Investigation on the physicochemical properties of poly (ethylene-co-vinyl acetate)/mesoporous silica nanocomposites: Effects of content and surface functionalization

In this study, poly (ethylene-co-vinyl acetate)/mesoporous silica EVA/SBA-15 nanocomposites, containing 0.5, 1.5, and 2.5 wt% of unfunctionalized and functionalized SBA-15 were prepared by melt blending in an internal mixer. Mesoporous silica was synthesized through the sol-gel method and modified by hexadecyltrimethoxysilane (HDTMS). Several characterizations were performed; including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties, dynamic mechanical analysis (DMA), and dielectric study to characterize the physicochemical properties of elaborated materials. The results revealed the successful synthesis and functionalization of mesoporous silica, as confirmed by the FTIR and SEM. The crystallinity of the nanocomposites decreased and the elastic modulus increased with the incorporation of the mesoporous silica. Measurement of tensile properties shows that the tensile strength of the nanocomposite content of 1.5 wt% F-SBA-15 is 17.2% is higher as compared to pure EVA. DMA analysis validates the improvement in mechanical properties of the EVA/SBA-15 samples. SEM images displayed well-dispersed F-SBA-15 nanoparticles and enhanced interfacial adhesion between the phases. TGA indicates the enhancement of the thermal stability of nanocomposites as compared with the pure EVA matrix. The surface functionalization presented an approach to preparing nanocomposites with enhanced thermal stability and a low dielectric constant.

Very Large Pore Mesoporous Bioactive Silicate Glasses: Comparison of Behavior toward Classical Mesoporous Bioactive Glasses in Terms of Drug Loading/Release and Bioactivity.

Considering the increase in patients who suffer from osteoporosis and the bone defects that occur in these patients, bone tissue regeneration is a promising option to solve this problem. To achieve a synergistic effect between the synthesis of a proper structure and bioactive/pharmaceutical activity, ions with a physiological effect can be added to silica structures, such as Ca2+, thanks to its bioactive behavior, and Ga3+ for its antibacterial and anticancer action. In this work, the synthesis of large pore mesoporous silica (LPMS), potential bioactive glasses containing Ca2+ and Ga3+, has been studied. Corresponding structures, in terms of composition, have been synthesized following the Sol-Gel EISA (Evaporation Induced Self-Assembly) process (obtaining Classical Mesoporous Silica, MS). Pore structure characterization of LPMSs and MSs has been performed using N2 adsorption/desorption and Hg-porosimetry, showing the presence of pores for LPMSs in the range of 20-60 and 200-600 nm. Nisin, a polycyclic antibacterial peptide, has been used for load tests. The load and release tests performed highlight a higher loading and releasing, doubled for LPMSs if compared to MSs. To confirm the maintenance of the structure of LPMSs and their mechanical strength and resistance, scanning electron microscopy images were acquired before and after release tests. Ca and Ga release in SBF has been studied through inductively coupled plasma-optical emission spectroscopy (ICP-OES), showing a particularly high release of these ions performed with LPMSs. The bioactive behavior of Ca-containing structures has been confirmed using FT-IR (Fourier-transform infrared spectroscopy), SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscopy), and X-ray powder diffraction (XRDP). In conclusion, LPMSs showed better loading and releasing properties compared with classical MS and better release in terms of active ions. In addition, it has also been demonstrated that LPMSs have bioactive behavior (a well-known characteristic of MSs).

Phosphonate functionalized magnetic mesoporous silica for rare earth element recovery from citrate assisted solid waste extracts

The growing high demand of rare earth elements (REEs) has prompted extensive research on REE recovery from waste streams. This study reports the synthesis and evaluation of phosphonate-functionalized magnetic mesoporous silica (MMS-PP) for REE recovery from the acidic extracts of solid wastes. MMS-PP was synthesized using surfactant template and post-synthesis methods, and tested using simulated and real extraction solutions from citrate-assisted REE extracts from municipal solid waste incineration (MSWI) ash. The organic-inorganic hybrid MMS-PP was evaluated for La recovery from 50 mM simulated citrate extract, with the adsorption capacity of 13.5 mg/g compared to ∼2.5 mg/g for non-functionalized MMS. The MMS-PP material exhibited fast adsorption within 10 min, good La selectivity against competing Na+ and Ca2+, moderate selectivity against Al3+ and Fe3+, high recyclability over multiple adsorption-desorption cycles, and equivalent efficiency for La, Ce, Nd, and Y recovery. The MMS-PP material also demonstrated 70–95% REE recovery from real citrate extracts of MSWI ash, and the spent MMS-PP material can be regenerated and reused for multiple cycles. Functionalized mesoporous materials in combination with organic-ligand assisted extraction can potentially provide a green, effective, and tunable solid-liquid separation platform for REE recovery from complex solid waste streams.

Synthesis of SBA-16 mesoporous silica from rice husk ash for removal of Rhodamine B cationic dye: Effect of hydrothermal treatment time

Recently, the use of silica-containing wastes has gained popularity as an excellent pathway to prepare mesoporous silica materials for applications of adsorption, catalysis and energy. Hence, this report aimed to prepare SBA-16 mesoporous silica samples derived from rice husk ash under varying times during hydrothermal treatment (viz., 24 and 48 h) and named as SBA-16–24 h and SBA-16–48 h. FE-SEM, TEM, XRD, FTIR, Raman and N2 gas adsorption at − 196°C tools were performed to explore the formation of SBA-16. Rhodamine B (RhB) dye uptake from aqueous solutions by both samples was determined by equilibrium isotherms and kinetics. Effects such as pH, dye initial concentration, temperature and contact time were investigated. Results revealed the successful preparation of SBA-16 with an amorphous, ordered mesoporous structure and a higher total surface area of 461 m2/g for SBA-16–48 h obtained during a longer time of hydrothermal treatment. Increasing the time of hydrothermal treatment to 48 h decreased the average particle sizes of SBA from 50–40 nm to 20–10 nm with enhancing the total surface area, mesopore volume and amount of Si-O-Si groups. Equilibrium adsorption isotherms were fitted better by the Langmuir model than the Freundlich Temkin and Dubinin-Radushkevich models. The maximum adsorption capacity calculated from Langmuir model showed that SBA-16–48 h featuring the larger capacity of about 166.7 mg/g at pH 6. Pseudo-second order kinetic is found to be more suitable to describe the adsorption. Negative values of ΔH0 and ΔS0 thermodynamic parameters affirmed that the adsorption of RhB dye is an exothermic and spontaneous process over prepared mesoporous silica. Conclusively, the investigated SBA-16–48 h is a promising adsorbent for effective removal of basic dyes from their aqueous stream.

Green synthesis of surfactant-free mesoporous silica with strong hydrophilicity via metal salt modifications for moisture adsorption

In this work, the green synthesis of mesoporous silica (MPS) was carried out using low-cost sodium silicate as a precursor.

An efficient and template‐free synthesis of mesoporous silica from coal fly ash

AbstractIn the study, the desilication liquids and acid‐leached residues derived from the “alumina extraction process” of coal fly ash (CFA) were used as raw materials to prepare sodium silicate precursor. Then, the mesoporous silica with controllable pore structure properties was synthesized by an efficient, template‐free process from obtained sodium silicate. The effect of the sodium silicate properties and synthesis conditions on the pore structure properties of disordered mesoporous silica were investigated. The resulting material was characterized by N2 adsorption–desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) and tested as an adsorbent for removal of lead ions (Pb2+). The results showed that the precursor with high modulus (3.0) and concentration (60 g·L−1) was beneficial for the synthesis of mesoporous silica with high specific surface area. The mesoporous silica with specific surface area of 690 m2·g−1 and pore volume of 1.28 cm3·g−1 was synthesized at mild aging temperature (40°C) and pH value of 8. Moreover, the materials possessed an adsorption capacity of 303 mg·g−1 for lead ions after amino modification. The adsorption efficiencies for lead ions were maintained at ~90% after five recovery cycles. Overall, the utilization efficiency of SiO2 in CFA reached up to 93%.

Smart Composite Coatings for Corrosion Protection

Corrosion is a major problem faced by the automobile industry. To overcome corrosion, the industry relies on surface coatings in which metallic (Zn, Cr etc.) and polymeric coatings (polyurethane, epoxy, etc.) are widely recommended. However, currently smart, self-healing coatings are considered to be the state of the art option to inhibit cut-edge corrosion and to enhance the life-time. The direct introduction of inhibitors into any matrix creates undesirable effects, majorly the integrity of the inhibitor with the matrix and spontaneous release. Hence, loading inhibitors into a suitable container and subsequent release of the same when the coating is damaged favors the self-healing property of a coating, which results in high durability.Such a smart coating can be achieved by the synthesis of porous silica particles, which can be an effective corrosion inhibitor container. They possess exceptional properties like nontoxicity, high surface area, and capability to be filled with different types of active materials, including organic, inorganic, and hybrid inhibitors. Hence, these can be the equivalent and non-toxic alternative to chromates which are toxic and carcinogenic to the environment and the living system.Among the different porous containers reported in the literature, mesoporous silica nanoparticles have large surface area which is beneficial to load the required quantity of corrosion inhibitors. The corrosion inhibitor-loaded porous silica containers are compatible with different matrices, including metals, polymers, and ceramics, to prepare the composite materials. To control the instant release of the loaded inhibitors, encapsulation with a polyelectrolyte is required. As a result, improved self-healing properties can be achieved as compared to the particles without encapsulation.Among the various types of porous silica, Santa Barbara Amorphous-15 (SBA-15) has several benefits, including the ease of preparation, nontoxic precursors, hexagonal structure to carry a high quantity of material, size range from micro to nanometer, controllable pore size (20-500Å), large specific surface area (∼1000m2/g), porosity, surface morphology and huge pore volume. This work describes the synthesis of mesoporous silica (SBA-15) using a three-step solvo-thermal process. The process includes template preparation (synthesis of mesoporous silica), loading with benzotriazole (BTA) an organic corrosion inhibitor, followed by Poly(diallyldimethylammonium chloride) (PDDA) encapsulation.The synthesised mesoporous silica was characterised for morphological features, porosity, and surface charge. Based on the BET analysis, successful modification of the mesoporous silica particles at different stages shows a reduction in the surface area and pore volume. The zeta (ζ)-potential measurements showed a significant variation in surface charge after the modification of the mesoporous silica particles. The releasing nature of BTA before and after the PDDA encapsulation was studied using UV-Visible technique at different pH levels. Based on the characterisation of the PDDA encapsulated inhibitor-loaded mesoporous silica particles, appropriate coating was prepared by incorporating these particles into eg. metallic (Zn coating) and/or polymeric (epoxy coating) matrices. The release and corrosion inhibition performance of these coatings were studied using electrochemical techniques. The multi-functional performance of these coatings would be highlighted.

Enhancing Cytochrome C Recognition and Adsorption through Epitope-Imprinted Mesoporous Silica with a Tailored Pore Size.

We have reported the synthesis of epitope-imprinted mesoporous silica (EIMS) with an average pore size of 6.2 nm, which is similar to the geometrical size of the target protein, cytochrome C (Cyt c, 2.6 × 3.2 × 3.3 nm3), showing great recognition and large-scale adsorption performance. The characteristic fragment of Cyt c was used as a template and docked onto the surface of C16MIMCl micelles via multiple interactions. Nitrogen adsorption-desorption and transmission electron microscopy confirmed the successful preparation of EIMS. Due to the ordered pore structure, larger pore size, and high specific surface area, the prepared EIMS show superior specificity (IF = 3.8), excellent selectivity toward Cyt c, high adsorption capacity (249.6 mg g-1), and fast adsorption equilibrium (10 min). This study demonstrates the potential application of EIMS with a controllable pore size for high-effective and large-scale separation of Cyt c, providing a new approach for effective biomacromolecular recognition.

Sustainable Sulfonic Acid Functionalized Tubular Shape Mesoporous Silica as a Heterogeneous Catalyst for Selective Unsymmetrical Friedel-Crafts Alkylation in One Pot.

The development of general and more sustainable heterogeneous catalytic processes for Friedel-Crafts (FC) alkylation reactions is a key objective of interest for the synthesis of pharmaceuticals and commodity chemicals. Sustainable heterogeneous catalysis for the typical FC alkylation of an easily accessible carbonyl electrophile and arenes or with two different arene nucleophiles in one-pot is a prime challenge. Herein, we present a resolution to these issues through the design and utilization of a mesoporous silica catalyst that has been functionalized with sulfonic acid. For the synthesis of sulfonic acid-functionalized mesoporous silica (MSN-SO3H), thiol-functionalized mesoporous silica was first synthesized by the co-condensation method, followed by oxidation of the thiol functionality to the sulfonic acid group. Sulfonation of mesoporous silica was confirmed by 13C CP MAS NMR spectroscopy. Further, the devised heterogeneous catalysis using MSN-SO3H has been successfully employed in the construction of diverse polyalkanes including various bioactive molecules, viz arundine, tatarinoid-C, and late-stage functionalization of natural products like menthol and Eugenol. Further, we have utilized this sustainable technique to facilitate the formation of unsymmetrical C-S bonds in a one-pot fashion. In addition, the catalyst was successfully recovered and recycled for eight cycles, demonstrating the high sustainability and cost-effectiveness of this protocol for both academic and industrial applications.

Particle size and morphology-selective synthesis of mesoporous silica and study of its interaction with human serum albumin: spherical versus rod-like shape

Mesoporous silica (MS) has gained considerable attention as a promising material for biomedical applications. The morphology of MS can affect its interaction with biomacromolecules, leading to changes in their biological performance. Herein, we aim to study human serum albumin (HSA) binding to spherical MS (SMS) versus rod-like MS (RMS). For this purpose, the Stöber method is exploited and the impact of synthesis variables on the MS morphology and size is examined. Next, the binding of SMS versus RMS with HSA is evaluated using fluorescence spectroscopy. The intrinsic fluorescence intensity changes show the combined dynamic and static quenching mechanism with the dominant contribution of the static mode in the MSs interaction with HSA. However, the RMS-HSA complex is more stable, with a binding constant of 0.03 × 106 M−1 at 37 °C compared to the SMS-HAS complex. The hydrophobic interaction is the driving force for SMS and RMS binding to HSA.

Synthesis and Characterization of Mesoporous Silica Supported Mn-Phosphomolybdate Nanocomposite for Ultra-Deep Desulfurization of Petroleum Oil Samples

Synthesis and Characterization of Mesoporous Silica Supported Mn-Phosphomolybdate Nanocomposite for Ultra-Deep Desulfurization of Petroleum Oil Samples

Synthesis of Graphene Oxide-Coated Mesoporous Silica with Cetyltrimethylammonium Bromide (CTAB) Template for Methylene Blue Adsorption

The synthesis of graphene oxide-coated mesoporous silica (MS_GO) with the template surfactant (Cetyltrimethylammonium Bromide) CTAB has been carried out. The effect of combining mesoporous silica and graphene oxide was studied by knowing the bonds, functional groups and crystalline structures. Functional groups C=O and C=C were formed at wave numbers 1,722, 1,617 and 1,647 cm−1, respectively, as a characteristic of GO compounds. XRD data showed that MS_GO has a more amorphous structure than graphite and GO due to the incorporation of silica onto the graphene oxide surface. The MS_GO synthesis was also applied as an adsorbent for methylene blue dye in water. The adsorption results showed that MS_GO was more effective than pure GO. The percent adorption efficiency (R %) of MS_GO against 10 ppm methylene blue was 93.1 % while that of pure GO was 91.5 %. The addition of mesoporous silica to graphene oxide makes MS_GO adsorbent more effective in adsorption dyes than pure GO, this is supported by the larger total surface area of BET MS_GO was 161.066 m2·g−1, while that of pure GO was 103.818 m2·g−1. HIGHLIGHTS Preparation of graphene oxide from graphite by the modified hummer method Mesoporous silica is synthesized with Graphene Oxide (GO) and occupies between GO layers in the GO interlayer space CTAB is used as a template and forms pores in the synthesis of layered Mesoporous Silica-Graphene Oxide (MS_GO) Graphene Oxide-Coated Mesoporous Silica will be applied for adsorption of methylene blue dye in water. The adsorption efficiency (% R) of GO against methylene blue is lower than % R of MS_GO against methylene blue GRAPHICAL ABSTRACT

Synthesis of ordered mesoporous silica from biomass ash and its application in CO2 adsorption

It is possible to achieve high-value utilization of solid wastes and lower the cost of mesoporous silica synthesis by synthesizing mesoporous silica from solid wastes. In this study, silica was extracted using the alkali fusion method using biomass ash as the starting material. Biomass ash based mesoporous silica was successfully prepared by hydrothermal method with silicon extract solution as silicon source. The optimum conditions for preparation were determined as follows: addition of cetyltrimethylammonium bromide was 0.45g, hydrothermal temperature was 120 °C, hydrothermal time was 24h. The prepared mesoporous silicon was systematically characterized, and the results showed that high surface area (495 m2/g) and ordered pore structure appeared in the synthesized mesoporous silica materials. The synthesized mesoporous silica showed excellent CO2 adsorption performance (0.749 mmol/g) at 25 °C and 1 bar. According to the calculation of adsorption isotherm and thermodynamics, non-linear Freundlich model can fit the adsorption isotherm better and the adsorption heat of mesoporous silica is less than 20 kJ/mol, which belongs to physical adsorption. After five cycles of CO2 adsorption, the adsorption property was still above 90%, and the CO2/N2 adsorption selectivity reached 396.6, showing good regeneration performance and adsorption selectivity. This research can provide a new possibility for the high-value exploitation of biomass ash and reducing the cost of synthetic mesoporous silica.

Synthesis and application of metal nanoparticles-loaded mesoporous silica toward the reduction of organic pollutants in a simple and binary system

Synthesis and application of metal nanoparticles-loaded mesoporous silica toward the reduction of organic pollutants in a simple and binary system

A green and multi-win strategy for coal fly ash disposal by CO2 fixation and mesoporous silica synthesis

Coal combustion provides plenty of energy, along with enormous coal fly ash (CFA) and CO2 emission. CFA could be recycled for mesoporous silica synthesis, but expensive templates are usually needed. In this work, we proposed a multi-win strategy using CO2 as the precipitator and template. Mesoporous silica powders, with a maximum specific surface area of 355.45 m2/g, a pore volume of 0.73 cm3/g, and an average pore size of around 7.67 nm, were synthesized. The influences of silicon concentration, CO2 flow rate, and ultrasound were investigated. In addition, the Na2CO3 by-product was produced with a purity of over 92 %. By averagely calculating, 1 ton CFA could generate 285 kg mesoporous silica and 1.02 t crude Na2CO3. Around 433 kg of CO2 could be absorbed. Therefore, multi-goals of CFA disposal, CO2 storage, and valuable silica materials production were realized, and the study could pave the way for large-scale industrial applications.