Mesoporous Microspheres Research Articles

Supported phenylalanine on core-shell mesoporous microsphere as a catalyst for the synthesis of triazolo[1,2-a] indazole-triones and spiro triazolo[1,2-a] indazole-tetraones

In recent years, mesoporous silica materials have gained attention due to their unique properties, such as high surface area, pore volume, size, and chemical stability. These characteristics make them effective in various fields, particularly efficient supports in heterogeneous catalytic reactions. The present study developed a novel type of core-shell mesoporous microsphere material by anchoring phenylalanine on a core-shell SiO2@NiO@MS support. The catalyst support (SiO2@NiO@MS) was synthesized through homogeneous precipitation and sol-gel methods, with NiO encapsulated within the porous silica. The catalyst was characterized using various techniques, including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), Elemental mapping analysis, N2 adsorption-desorption, Transmission electron microscopy (TEM), Vibrating sample magnetometer (VSM), and Thermogravimetric analysis (TGA). It was then employed for the synthesis of triazolo[1,2-a]indazole-trione and spiro triazolo[1,2-a]indazole-tetraones compounds from 4-phenyl urazole, dimedone, and aromatic aldehydes or isatin derivatives. This synthetic approach offers multiple advantages, including high yields, faster reaction times, low catalyst requirements, and environmentally sustainable conditions.

Mesoporous Silica Supported Hydrophilic Ionic Liquid Gel Microspheres for Solvent-Free Deep Oxidative Desulfurization.

Solvent-free oxidative desulfurization can avoid environmental pollution caused by organic solvents as well as prevent loss of fuel during the oil-water separation process. In this work, first, hydrophilic ionic liquid gel microspheres with [BMIM]BF4 and PHEMA as the dispersion medium and gel network, respectively, were successfully prepared by using mesoporous silica microspheres as a supporting skeleton capable of stabilizing the gel through an anchoring effect, and then the catalyst [BMIM]PW and oxidant H2O2 were incorporated into the gel microspheres to construct a liquid compartment microreactor for deep desulfurization. The prepared microreactor (SiO2@[BMIM]PW/ILG-microspheres) has excellent extraction-catalytic capacity and exhibited ∼100% desulfurization ratio for a model oil of n-heptane with 500 ppm of DBT at 60 °C for 3 h without solvents. Additionally, the prepared microreactor can absorb hydrophilic desulfurization products after the reaction and has advantages of reusability and simple recovery without polluting the fuel oil, which is beneficial for potential petroleum industrial application.

Evaluation of acute and subacute dermal toxicity of antibacterial bioactive glass-infused surgical cotton gauze in Wistar rats

Mesoporous bioactive glass, with its versatile characteristics and morphology, holds significant potential as an ideal hemostatic material. However, limited data is available regarding its toxicity levels. Consequently, this research intends to assess the acute and repeated dose dermal toxicity of Mesoporous antibacterial bioactive glass microsphere impregnated nonwoven surgical cotton gauze (MABGmscg) dressing in albino Wistar rats, following the standards set by the Organization for Economic Cooperation and Development. In the acute dermal toxicity study, the impact of MABG (@2000mg/kg BW) mscg dressing was assessed following a single dermal application in both male and female Wistar rats (n = 10). Mortality, clinical signs, body weight fluctuations and gross observations were consistently monitored over a14 day period following the single dose. The results indicated that, MABG (@2000mg/kg BW) mscg dressing upon dermal exposure did not cause any adverse effect in acute dermal toxicity study in Wistar rats compared to control group. Given that 2000 mg/kg BW of MABG was deemed a nontoxic dose, a repeated dose dermal toxicity study of MABGmscg dressing was subsequently conducted at three dose levels (@200, 500, 1000 mg/kg BW) over 28 consecutive days in Wistar rats. During the study period, no unscheduled deaths occurred, and there were no clinical signs associated with treatment, body weight variations or abnormal gross findings at necropsy in any groups. The analysis concluded that, MABGmscg dressing is safe to be considered as a hemostatic dressing at the various tested dose levels in Wistar rats.

Synthesis of Self-Assembled Mesoporous ZnO Microspheres Designed for Microwave-Assisted Photocatalytic Degradation of Tetracycline.

Microwave-assisted photocatalysis offers a novel approach for degrading antibiotics, while the mechanism of enhancement of microwave-induced photocatalysis remains poorly understood. In this study, tetracycline (TC) was degraded using the method of microwave-assisted photocatalysis with a ZnO catalyst, which was synthesized by the combination of hydrothermal and calcination methods. The self-assembled mesoporous ZnO catalyst exhibited superior catalytic activity in degrading TC. It is found that the degradation efficiency of TC by the ZnO catalysts with microwave-assisted photocatalysis is 4.27 times higher than that of photocatalysis alone. Of particular significance, we found that the optical absorption range of ZnO increased and the band gap decreased when microwave was introduced into the photocatalytic system. Semi-in situ photochemical tests demonstrated that more photogenerated electron-hole pairs were detected under microwave, thus further improving the photocatalytic activity of ZnO. The separation efficiency and charge transfer efficiency of photogenerated electron-hole pairs also improved due to the increase of oxygen vacancies in the synergistic effect. Meanwhile, h+ and ·OH were the main active species in the degradation system. The mechanism of microwave-induced photocatalysis is illustrated, and an efficient way for degrading antibiotic is provided in this work.

Impact of Surface Chemistry and Particle Size on Inertial Cavitation Driven Transport of Silica Nanoparticles and Microparticles

AbstractThis study investigated the high‐intensity focused ultrasound (HIFU)‐mediated propulsion of mesoporous silica nanoparticles (MSNs) and microspheres (MSMs). Nanoparticles are heavily sought as vehicles for drug delivery, but their transport through tissue is often restricted. Here, MSNs and MSMs are hydrophobically modified and coated with phospholipids to facilitate inertial cavitation to promote propulsion under HIFU. Modified nanoparticles show significantly enhanced cavitation and propulsion, achieving a maximum displacement of 250 µm (≈2500 body length) and speed of ≈1600 µm s−1 (16 000 body length s−1), compared to unmodified nanoparticles (2 µm, 20 body length, 60 µm s−1, 600 body length). In contrast, microparticles demonstrate comparable cavitation responses. Modified microparticles reached a maximum speed of 4000 µm s−1 (800 body length s−1) and displacement of 230 µm (46 body length), and unmodified microparticles achieved 2000 µm s−1 (400 body length s−1) and 75 µm (15 body length). In all HIFU‐responsive samples, displacement and speed decreased with successive pulses, implying that particles fatigue with continued pulsing. Analyses of particle trajectories and rotational diffusion times suggest that cavitation occurs uniformly on particle surfaces rather than at specific sites. These principles are important for the design of future drug‐delivery vehicles capable of ultrasound‐triggered motion.

The adsorption of cesium by sulfonic acid functionalized hollow mesoporous silica microspheres

With the development of nuclear industry, radioactive elements such as 137Cs put a threat on the water environment. It is a challenging task to remove the Cs+ in the nuclear wastewater. In the current study, we prepared a new Cs+-adsorbing material by introducing sulfhydryl group onto the surface of hollow mesoporous silica microspheres, then oxidizing the sulfhydryl group to sulfonic acid group. The obtained HMSS-SO3H material had an excellent adsorption capacity for Cs+ in the aqueous solution, with an adsorption capacity of 51.53 mg g−1 in 30 min. Characterization approaches, such as FT-IR and EDS, were used to confirm the result of modification. Adsorption experiments were carried out under. The influence of various parameters on the adsorption process was investigated under the conditions of changing pH, temperature, and time. The effect of competitive ions was also explored. The results indicated that the adsorption process followed the pseudo-second-order model and the main adsorption mechanisms are electrostatic interaction and coordination. The material had a best adsorption performance at a neutral pH. The adsorption process could well-fit the Langmuir's model, with a theoretical maximum adsorption capacity of 81.31 mg g−1. And the adsorption capacity was slightly affected by competing ions such as Mg2+ and Ca2+. The results indicate that the HMSS-SO3H prepared in this study is a promising adsorbent for Cs+, with the advantages of high adsorption capacity, fast adsorption rate and high selectivity.

Multi-shell bowl-like carbon microspheres for lightweight and broadband microwave absorption

Carbon materials have made significant progress in the field of microwave absorption (MA), but achieving wide effective absorption bandwidth (EAB) at low filler content still remains a great challenge. In this work, we design multi-shell bowl-like mesoporous carbon microspheres (MBMCs) by a facile hard template method for efficient MA. It is demonstrated that the spacing between inner and outer shell and second shell thickness play a vital role on the configuration of carbon microspheres. By controlling the second addition of silica template, the microstructure of carbon microsphere evolves from spherical to bowl shape geometry. Expanded shell spacing is beneficial for forming bowl-like microsphere. The dielectric loss and MA properties are highly associated with the configuration of MBMCs. Well-proportioned MBMCs with appropriate shell spacing present wide EAB of 7.3 GHz under a low filling ratio of 12 wt.%. This work paves a new way to broaden EAB and lower filling content of carbon materials via asymmetric multilayer microstructure design.

Thermally-switchable adsorbent for selective uranium extraction from wastewater

Uranium extraction from uranium-containing wastewater is a promising solution to the uranium resource shortage, but the extraction process faces significant challenges such as poor selectivity, low elution efficiency, and recovery difficulties. In this study, we developed thermally responsive uranium ion-imprinted magnetic mesoporous microspheres (Fe3O4@mSiO2@FIIP) using polymer F-127 as a thermosensitive switch and sodium phytate as a crosslinking monomer, enabling effective uranium recovery from uranium-containing wastewater. By adjusting the adsorption and elution temperatures, Fe3O4@mSiO2@FIIP achieved higher adsorption selectivity and elution efficiency compared to ion-imprinted magnetic mesoporous microspheres without F-127 (Fe3O4@mSiO2@IIP). Additionally, Fe3O4@mSiO2@FIIP demonstrated superior selectivity for uranium ions over other cations compared to non-imprinted magnetic mesoporous microspheres (Fe3O4@mSiO2@NIP). It exhibited excellent salt resistance, reaching adsorption equilibrium within 60 min with a maximum adsorption capacity of 529.5 mg/g. Life cycle assessment (LCA) and techno-economic assessment (TEA) indicated that Fe3O4@mSiO2@FIIP is more environmentally friendly and economically feasible for treating uranium-containing wastewater. This study provides a new paradigm for synthesizing thermosensitive imprinting materials, holding significant potential for uranium recovery applications.

Theoretical study of size and shell composition effect of TiO2 core-shell mesoporous microsphere on UV absorption effectivity for photocatalytic application

Theoretical study of size and shell composition effect of TiO2 core-shell mesoporous microsphere on UV absorption effectivity for photocatalytic application

Boosting the potassium storage property of spongia-like copper phosphide anode via nano-in-micro construction

Metal phosphides (MPs) show great promise as anode material in potassium-ion batteries (PIBs) owing to their cost-effectiveness and high theoretical capacity. Despite that, MPs anode usually manifests inferior poor cyclability as a result of dramatic volume fluctuation during discharge–charge cycling. Herein, a scalable salt template-assisted spray-drying method is developed to fabricate the porous carbon microspheres wrapped CuP2 nanoparticles (p-CuP2/C) with a nano-in-micro structure. The combination of the CuP2 nanoparticles, large meso-porous carbon microspheres can simultaneously offer plenty of reactive sites, promote electrolyte penetration, and maintain structural integrity. Additionally, the proposed synthesis strategy is suit for the industrial manufacture. As an anode for PIBs, the p-CuP2/C anode presents a high reversible capacity (494 mAh/g at 0.05 A/g), excellent cycling stability (a capacity degradation rate of 0.04 % per cycle during 2000 cycles at 2 A/g), and superior rate capability (244 mAh/g at 2 A/g). More impressively, pairing with a potassium Prussian blue cathode, the potassium-ion coin cell shows an excellent cycling lifespan with 87.1 % capacity retention after 200 cycles at a current density of 0.1 A/g, the assembled pouch cell also maintains stable cycling at 0.3 A/g over 80 cycles. This research could offer a facile approach to develop other advanced anodes with industrial practicability for alkali ion batteries.

Hematite nanomaterial from a tropical freshwater ecosystem: Geological, environmental, and industrial implications

Synthetic hematite (Fe2O3) nanoparticles are extensively explored for medicine, optics, and environmental remediation. However, natural iron nanoparticles in a freshwater ecosystem have not been well characterized. Here we report the presence of natural iron nanoparticles in a tropical freshwater ecosystem in southern India. These iron nanoparticles that exist as slime in the natural water system were characterized through a multiproxy investigation involving Field-Emission Scanning Electron Microscopy (FE-SEM), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), X-ray Photoelectron Spectroscopy (XPS), and Raman spectroscopy and BET analyses. These nanoparticles exist as amorphous hematite (Fe2O3), with the XRD peaks matching that of the iron arsenate compound. Fe2O3 occurs as mesoporous hollow microspheres with a size range of 14.97 to 61.3 nm and a surface area of 48.45m2/g. Further, the identification of Bacillus cereus in the slime suggests its role in iron sequestration, indicating a biogeochemical origin, which we infer is a particularly common phenomenon in tropical river basins where lateritic soils prevail. This study is the first to describe natural iron nanoparticles in a tropical freshwater ecosystem. It identifies their amorphous hematite structure and biogeochemical origin, offering new insights into their ecological roles and potential applications. This discovery presents an opportunity for utilizing this slime as an important source of hematite nanomaterials, with potential industrial applications.

Synthesis of Co/Ni-Doped mesoporous spinel ferrite microspheres for enhanced Low-Temperature SCR performance

The iron-based catalysts commonly used in the selective catalytic reduction (SCR) process cannot meet the increasingly stringent low-temperature NOx emission targets. In this study, mesoporous microspherical MFe2O4 (M=Co, Ni) spinel ferrite catalysts were synthesized by hydrothermal method and applied to the SCR of ammonia (NH3-SCR) reaction. Compared to Fe3O4, both NiFe2O4 and CoFe2O4 catalysts showed higher SCR catalytic activity at low temperature. The NiFe2O4 catalyst achieved a NO conversion of 95.5 % at 240 °C, while CoFe2O4 exhibited a high NO conversion of 97.6 % at 180 °C and a N2 selectivity of 99.6 %. Various characterization experiments revealed that the introduction of Co and Ni resulted in the formation of a specific mesoporous microsphere morphology in CoFe2O4 and NiFe2O4 catalysts, along with the generation of a large number of oxygen vacancies and acidic sites on the surface. These features facilitate the sequential adsorption and activation of NH3 and NOx species, resulting in excellent catalytic activity at low temperatures. Detailed in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) measurements showed that on NiFe2O4 the reaction follows the Eley–Rideal (E–R) mechanism, whereas it proceeds through the Langmuir–Hinshelwood (L–H) and Eley–Rideal (E–R) mechanisms on the CoFe2O4 catalyst. This work provides a feasible strategy for enhancing the low-temperature SCR reaction over iron-based catalysts; moreover, the elucidation of the complete reaction mechanism offers a solid foundation for future improvements in denitrification catalysts.

PH-responsive chitosan-mediated spherical mesoporous silica microspheres for high loading and controlled delivery of 5-Fluorouracil

The objective of this study is to develop a drug carrier to overcome the inherent drawbacks of 5-Fluorouracil (5-Fu), including low bioavailability, short half-life, and systemic toxicity. In the present work, mesoporous silica nanoparticles (MSNs) capped by chitosan (CS) to encapsulate 5-Fu (5-Fu MSNs/CS) were fabricated by the sol-gel process, ultrasonic impregnation, and emulsion cross-linking. The 5-Fu MSNs/CS microspheres exhibit pH-responsive drug release and remarkable drug encapsulation capacity, as well as perfect sphericity, high specific surface area (680.62 cm2/g), and uniform particle size (2.64 ± 0.05 μm). The drug-loading content and encapsulation efficiency are 14.12 ± 0.53 % and 82.21 ± 2.13 %, respectively. The cumulative release of 5-Fu from MSNs/CS microspheres is fast and sustained at pH 5.0 (89.56 ± 0.97 %) compared to that at pH 7.4 (57.88 ± 0.91 %) in 96 h, and it is Fickian diffusion controlled. In conclusion, the MSNs/CS microspheres prepared in this study could be potential carriers for 5-Fu delivery.

Acute dermal irritation and skin sensitization study of mesoporous antibacterial bioactive glass microsphere impregnated surgical cotton gauze dressing material on rabbits and guinea pigs

Acute dermal irritation and skin sensitization study of mesoporous antibacterial bioactive glass microsphere impregnated surgical cotton gauze dressing material on rabbits and guinea pigs

Preparation of Monodisperse Silica Mesoporous Microspheres with Narrow Pore Size Distribution.

The purpose of this study is to prepare monodisperse silica mesoporous microspheres with narrow pore size distribution to promote their application in the field of liquid chromatography. An improved emulsion method was used to prepare silica mesoporous microspheres, and the rotary evaporation temperature, emulsification speed, dosage of porogen DMF, and dosage of the catalyst NH3·H2O were optimized. Subsequently, these microspheres were respectively treated by alkali-heating, calcination, and sieving. The D50 (particle size at the cumulative particle size distribution percentage of 50%) of as-prepared silica mesoporous microspheres is 26.3 μm, and the D90/D10 (the ratio of particle size at a cumulative particle size distribution percentage of 90% to a cumulative particle size distribution percentage of 10%) is 1.94. The resultant silica mesoporous microspheres have distinctive pore structures, with a pore volume of more than 1.0 cm3/g, an average pore size of 11.35 nm, and a median pore size of 13.4 nm. The silica mesoporous microspheres with a large particle size, uniform particle size distribution, large average pore size and pore volume, and narrow mesopore size distribution can basically meet the requirements of preparative liquid chromatographic columns.

Directed self-assembly of mesoporous starch-based microparticle: Characterization, antimicrobial activities, and digestibility

Porous starch has garnered increasing interest due to its distinctive properties and versatile applications. Here, we propose a sustainable and efficient method for producing highly uniform mesoporous starch-based microspheres (CSMP) with adjustable sizes through the directed self-assembly of short-chain glucan (SCG) using chitosan. Chitosan facilitates the layer-by-layer deposition of SCG nuclei in the circumferential direction, resulting in the formation of a porous structure on CSMP. By controlling the concentration of SCG, the particle size can be precisely tuned within the range of 400 nm–900 nm. The resulting CSMP exhibit enhanced properties compared to starch-based microspheres formed without chitosan, including a surface area of 20.54 m2/g, total pore volume of 0.13 cm³/g, average pore diameter of 25.5 nm, and water absorption capacity of 352.6%. Moreover, CSMP demonstrate remarkable antibacterial activity (over 93%) against Escherichia coli and Staphylococcus aureus, while containing a high level of resistant starch (over 60%), highlighting their potential for the development of functional foods.

PH-responsive Aminated mesoporous silica microspheres modified with soybean hull polysaccharides for curcumin encapsulation and controlled release

Mesoporous silica microspheres (MSMs) possess poor biocompatibility. This study focuses on integrating MSMs with polymers to obtain hybrid materials with superior performance compared to the individual components and responsive release in specific environments. The synthesized MSMs were aminated, and subsequently, soybean hull polysaccharide (SHPs) was modified onto MSMs-NH2 to produce MSMs-NH2@SHPs nanoparticles. The encapsulation rate, loading rate of curcumin (Cur), and in vitro release behavior were investigated. Results indicated that the encapsulation efficiency of Cur by MSMs-NH2@SHPs nanoparticles reached 75.58%, 6.95 times that of MSMs-NH2 with a load capacity of 35.12%. It is noteworthy that these nanoparticles exhibit pH-responsive release capacity in vitro. The cumulative release rate of the three nanoparticles at pH 5.0 was higher than that at pH 7.4. MSMs-NH2@SHPs had a cumulative release rate of 56.55% at pH 7.4, increasing to 76.21% at pH 5.0. In vitro experiments have shown that MSMs-based nanoparticles have high delivery efficiency and can achieve pH-sensitive drug release, with a high release rate in a slightly acidic acid, highlighting the potential for controlled release of Cur.

Mesoporous Cu2O microspheres for highly efficient C2 chemicals production from CO2 electroreduction

Production of C2 chemicals (such as C2H4, C2H5OH, etc.) from CO2 electroreduction reaction (CO2ER) has been regarded as a promising route to solve the environmental problems and energy crisis. In this work, mesoporous Cu2O microspheres of ca. 700 nm diameter size with low crystallinity were fabricated to enable efficient conversion of CO2 to C2 chemicals by electrocatalytic reduction. It is revealed that compared with bulk Cu2O, the obtained mesoporous Cu2O microspheres have larger surface area, more grain boundaries and defects (unsaturated coordination sites), which facilitate the adsorption and stabilization of the important intermediates, such as *CO, on the route to C2 chemicals formation. As a result, the Faraday efficiency (FE) of C2 products reaches as high as 82.6 % and 78.5 % in an H-cell and a flow cell, respectively. In situ Raman and FT-IR spectra reveal that during CO2ER test there exists abundant *CO on the mesoporous Cu2O surface, thus increasing the opportunity of CC coupling. And the high coverage of *CO on catalyst surface during CO2ER protects and stabilizes the oxidation state of Cu species. This work demonstrates an effective strategy to introduce mesoporous structures and decreased crystallinity for improving the performance of CO2ER to C2 products.

The tune of shell numbers of multi-shell hollow mesoporous carbon microspheres for enhanced microwave absorption

The morphology of carbon nanomaterials plays significant effect on the complex permittivity and microwave absorption (MA) capability. Elaborate morphology design would bring about efficient MA performance. In this work, we develop a hollow mesoporous carbon microspheres with different shells (from single to quadruple shells) through a facile template method and layer-by-layer etching process. This multi-shell hollow mesoporous carbon microspheres (MS-HMCMs) can be regarded as a complex composite morphology consisting of hollow, mesoporous and yolk-shell structure, which presents the tunable number of shells for optimal impedance matching, multiple interfacial polarization and the extended microwave transmission path from internal spaces. Thus, the MS-HMCMs demonstrates wide effective absorption bandwidth (EAB) of 6.4 GHz and 5.96 GHz at the thicknesses of 2.5 mm and 3.0 mm. Besides, the complex permittivity and MA properties can be effectively tuned via regulating the shell numbers. This MS-HMCMs with controllable shells may be a promising wideband and lightweight microwave absorber.

Mesoporous Mn-substituted MnxZn1-xCo2O4 ternary spinel microspheres with enhanced electrochemical performance for supercapacitor applications.

Extensive investigations have been carried out on spinel mixed transition metal oxide-based materials for high-performance electrochemical energy storage applications. In this study, mesoporous Mn-substituted MnxZn1-xCo2O4 (ZMC) ternary oxide microspheres (x = 0, 0.3, 0.5, 0.7, and 1) were fabricated as electrode materials for supercapacitors through a facile coprecipitation method. Electron microscopy analysis revealed the formation of microspheres comprising interconnected aggregates of nanoparticles. Furthermore, the substitution of Mn into ZnCo2O4 significantly improved the surface area of the synthesized samples. The electrochemical test results demonstrate that the ZMC3 oxide microspheres with an optimal Mn substitution exhibited enhanced performance, displaying the largest specific capacitance of 589.9Fg-1 at 1Ag-1. Additionally, the ZMC3 electrode maintained a capacitance retention of 92.1% after 1000 cycles and exhibited a significant rate capability at a current density of 10Ag-1. This improved performance can be ascribed to the synergistic effects of multiple metals resulting from Mn substitution, along with an increase in the surface area, which tailors the redox behavior of ZnCo2O4 (ZC) and facilitates charge transfer. These findings indicate that the incorporation of Mn into mixed transition metal oxides holds promise as an effective strategy for designing high-performance electrodes for energy storage applications.