Pores Of Carrier Research Articles

Preparation and stability of zinc‐based mesoporous sorbent modified with aluminium for high temperature coal gas desulphurization

AbstractZinc‐based sorbents with ordered mesoporous structure were modified with aluminium and the key factors in the preparation were optimized based on the results of desulphurization tests performed in a fixed‐bed reactor with simulated coal gas. It was shown that the sorbents for hydrogen sulphide removal reached an optimum sulphur capacity of 9.14% when prepared under conditions of 10.0 crystalline pH, 30:1 Si:Al molar ratio, 0.32:1 Zn:Si molar ratio, and 1:3 Zn:TAA molar ratio. The sorbent without aluminium was synthesized synchronously as a comparison sample to investigate the effect of aluminium addition on the desulphurization properties. The surface acidity of the sorbents is enhanced by the addition of aluminium, and the sulphur capacity of the aluminium‐doped sorbent is consequently lower compared to that of aluminium‐free sorbent. Nevertheless, the aluminium‐doped sorbent shows a significant advantage in stability of performance over multiple desulphurization–regeneration cycles and reaches an 81% retention rate of sulphur capacity after five desulphurization, while the aluminium‐free sorbent is only 51% in contrast. The characterization results manifest that aluminium enters the carrier skeleton and increases the wall thickness, which alleviates the collapse of the carrier pore channels and the agglomeration of the active components during the desulphurization process. Stable pore structures and highly dispersed active components facilitate the mass transfer in the reaction process after multiple desulphurization. As a result, the aluminium‐doped sorbent exhibits better performance stability in high temperature coal gas desulphurization.

Characterization and photocatalytic properties of porous ZrO2/Al2O3 ceramic bead supported BiOI catalyst

Porous ZrO2/Al2O3 ceramic bead carriers were prepared through the gel-dripping method using sodium alginate as gelling agent with sucrose as pore-forming agent. The BiOI photocatalyst was loaded on the porous ceramic bead carrier with the solvothermal method. The effects of sucrose content and sintering temperature on the pore structure, porosity and compressive strength of the carriers were investigated. The influences of reaction time and reaction temperature on the microstructure and visible light photocatalytic properties of supported BiOI catalyst were also studied. The results show that, the porous ceramic bead with 30 wt% sucrose content sintered at 1300 °C exhibits a porosity of 71.60 % and a compressive strength of 5.06 MPa, which is suitable for the catalyst carrier. BiOI nanosheets assemble into microspheres with bonding force in the supported BiOI catalyst. BiOI microspheres distribute on the surface or in the pores of carriers. The supported BiOI catalyst prepared at 160 °C soaking for 6 h exhibits the highest degradation rate of 98.5 %. The microsphere diameter, loading amount, and photocatalytic activity of supported BiOI can be regulated through optimizing the reaction time and reaction temperature of solvothermal method. Compared with BiOI powder, the supported BiOI catalyst is easily recycled.

An Immobilized Amine with Improved Cyclic Performance Prepared from Carboxyl Modified Mesoporous Silica for CO2 Capture

AbstractImmobilized amines adsorbents have excellent CO2 adsorption capacity and low regeneration energy consumption, which have broad application prospect, but poor reusability. To improve the cyclic adsorption performance of immobolized amines for CO2 capture, the mesoporous silica A‐MSU‐J with carboxyl groups on the surface was synthesized, and immobilized amine A‐MSU‐J‐TEPA was prepared by introducing tetraethylenepentamine (TEPA) by impregnation method. The introduction of carboxyl groups onto the carrier surface can form stronger hydrogen bonds with TEPA than the initial hydroxyl groups, thus achieving stable loading of TEPA. When the TEPA load was 50 wt %, the adsorption capacity of 4A‐65MSU‐J‐50TEPA declined by only 13.7 % (from 2.58 to 2.23 mmol ⋅ g−1, at 70 °C, 0.1 Mpa) after 10 cycles, while the adsorption capacity of 65MSU‐J‐50TEPA decreased by 23.6 % (from 2 to 1.53 mmol ⋅ g−1). Furthermore, carrier pore size also affects the adsorption capacity of immobilized amines for CO2. The adsorption capacity of 4A‐65MSU‐J‐50TEPA with larger pore size (2.95 mmol ⋅ g−1, at 55 °C) is much higher than that of 4A‐25MSU‐J‐50TEPA with smaller pore size (2.17 mmol ⋅ g−1). In conclusion, improving the interaction between organic amines and the carrier surface and using carriers with larger pore size can enhance the adsorption capacity and reusability of immobolized amines adsorbents.

Effect and mechanism of ultrasound on acid loading in the preparation of silicon-based sulfonic solid acids

Silicon-based sulfonic solid acids have the advantages of high catalytic activity and selectivity, easy separation from products, low equipment corrosion, and environmental protection, and sulfuric acid loading is the key to their preparation. To overcome the shortcomings of low acid loading and uneven distribution in the existing preparation methods of micron-sized silicon-based sulfonic solid acids, a method was proposed to prepare micron-sized silicon-based sulfonic solid acids using ultrasonic enhanced technology. The effect of different reaction parameters, such as time, power, and temperature of ultrasonication, sulfonation temperature and time, and sulfuric acid concentration, on acid loading in solid acid was investigated in this work. The results showed that a micron-sized mesoporous silica-based solid acid was successfully synthesized with a high acid content of 0.8633 mmol/g, uniform acid distribution, high specific surface area of 269.332 m2/g, and large average particle size of 172.142 μm in this work. The introduction of ultrasound was found to expand the carrier's pore volume and increase the carrier's specific surface area and the number of hydroxyl groups, thereby increasing the acid loading capacity and the specific surface area of the solid acid sample by 66.6 % and 10.97 % respectively, compared with the case without ultrasound.

Fischer–Tropsch Synthesis Catalysts for Selective Production of Diesel Fraction

The Fischer–Tropsch process is considered one of the most promising eco-friendly routes for obtaining synthetic motor fuels. Fischer–Tropsch synthesis is a heterogeneous catalytic process in which a synthesis gas (CO/H2) transforms into a mixture of aliphatic hydrocarbons, mainly linear alkanes. Recently, an important direction has been to increase the selectivity of the process for the diesel fraction. Diesel fuel synthesized via the Fischer–Tropsch method has a number of advantages over conventional fuel, including the high cetane number, the low content of aromatic, and the practically absent sulfur and nitrogen impurities. One of the possible ways to obtain a high yield of diesel fuel via the Fischer–Tropsch process is the development of selective catalysts. In this review, the latest achievements in the field of production of diesel via Fischer–Tropsch synthesis using catalysts are reviewed for the first time. Catalytic systems based on Al2O3 and mesoporous silicates, such as MCM-41, SBA-15, and micro- and mesoporous zeolites, are observed. Together with catalytic systems, the main factors that influence diesel fuel selectivity such as temperature, pressure, CO:H2 ratio, active metal particle size, and carrier pore size are highlighted. The motivation behind this work is due to the increasing need for alternative processes in diesel fuel production with a low sulfur content and better exploitation characteristics.

The microstructure and photocatalytic properties of nitrogen-doped nano titanium dioxide loaded on porous ceramics

Nitrogen-doped nano TiO2 powder was prepared using the solvothermal method. The nano TiO2 powder was loaded on the porous ceramic carriers with a different aperture through the vacuum impregnation method using polyvinyl alcohol as a binder. The effects of deionized water content and carrier pore size on the microstructure and photocatalytic activity of nitrogen-doped nano TiO2 powder and supported TiO2 were investigated. The results show that, when introducing 25% deionized water, the nitrogen-doped nano TiO2 powder obtains a good crystallinity, small grain size, and high photocatalytic properties because of adequate hydrolysis of tetrabutyl titanate. The photocatalytic activity of nitrogen-doped nano TiO2 powder is improved by distorting the lattice and inhibiting grain growth. The nano TiO2 powder can be tightly loaded on the surface of the strut or hole-wall of porous ceramic carriers. The absorption and photocatalytic activity of supported TiO2 are demonstrably improved as the macropore provides the transmission channel, and the micropore realizes a good absorbing effect. The 20 PPI carrier with high porosity and suitable strength is beneficial to promote the photocatalytic property of supported TiO2. Moreover, the supported TiO2is easily recycled and reused.

Walnut shell derived bio-carbon/methyl palmitate as novel composite phase change material with enhanced thermal energy storage properties

Two kinds of bio-carbons were developed by carbonization/and chemical activation of walnut shell (WS) as lightweight, porous, low-cost and environmental friendly supporting matrix. The produced walnut shell carbon (WSC) and activated WSC (AWSC) were evaluated as novel shape stabilizer and thermal conductivity enhancer for methyl palmitate (MP) preferred as phase change materials (PCM) for thermal controlling applications in buildings. The surface area and pore volume of WS was increased by 1.47 and 1.44 times, respectively after its chemical activation process. WSC and activated AWSC significantly prevented the leakage of liquid MP through phase change due to their suitable adsorption capacities reaching 43 and 55%, respectively. The SEM investigation demonstrated that the MP was well confined into pores of CHW and ACHW carriers. The FTIR and XRD examinations proved the presence of well physicochemical compatibility between the components of the leak-free composites. The DSC measurements indicated that the melting temperatures of WSC/MP and AWSC/MP were 26.27 and 26.65°C, and corresponding fusion enthalpies were 108.3 and 138.1 J/g, respectively. The leak-free composite PCMs were showed remarkable chemical structural stability and thermal reliability after 1000 heating/cooling cycles. Both composites had considerably high thermal degradation stability. The thermal conductivity of leak-free WSC/MP and AWSC/MP was measured as about 1.9 and 1.58 times higher than that of MP. All findings revealed that the leak-free composite PCMs can be used as admixture in the manufacture of lightweight, cost-effective, eco-friendly and energy-saving construction elements utilized for solar thermal controlling of buildings.

Effect of operating conditions and TWC parameters on emissions characteristics of a China-VI stoichiometric natural gas engine

This study involved conducting an experimental and numerical investigation on the effects of the air-to-fuel ratio (AFR), engine speed, and engine load on the inlet gas component of a three-way catalyst (TWC) and on the effects of noble metal loading, noble metal ratio, and carrier pore density on the emission conversion efficiency. The results showed that AFR can significantly affect the raw emissions of NOx and THC, and better emission conversion efficiency of a TWC can be reached when AFR is controlled between 0.995 to 1. Compared with engine speed, engine load has a relatively small effect on exhaust temperature but greatly affects the flow velocity and NOx and THC emissions. Increasing the content of Pt in the catalyst can improve the THC conversion efficiency. For low Pt and Pd-Rh catalysts, the THC conversion effect is significantly deteriorated. The content of Rh affects the NOx conversion, and NOx conversion efficiency at high speeds is significantly reduced when Rh content is reduced. Higher carrier pore density can slightly improve the catalytic reaction rate and emission conversion efficiency at high engine speeds. However, high conversion efficiency can be maintained even after aging.

Effect of Operating Conditions and TWC Parameters on Emissions Characteristics of a Stoichiometric Natural Gas Engine

This study involved conducting an experimental and numerical investigation on the effects of the air-to-fuel ratio (AFR), engine speed, and engine load on the inlet gas component of a three-way catalyst (TWC) and on the effects of noble metal loading, noble metal ratio, and carrier pore density on the emission conversion efficiency. The results showed that AFR can significantly affect the raw emissions of NOx and total hydrocarbon (THC), and better emission conversion efficiency of a TWC can be reached when AFR is controlled between 0.995 to 1. Compared with engine speed, engine load has a relatively small effect on exhaust temperature but greatly affects the flow velocity and NOx and THC emissions. Increasing the content of Pt in the catalyst can improve the THC conversion efficiency. For low Pt and Pd-Rh catalysts, the THC conversion effect is significantly deteriorated. The content of Rh affects the NOx conversion, and NOx conversion efficiency at high speeds is significantly reduced when Rh content is reduced. Higher carrier pore density can slightly improve the catalytic reaction rate and emission conversion efficiency at high engine speeds. However, high conversion efficiency can be maintained even after aging.

Thiophene HDS on La-Modified CoMo/Al2O3 Sulfided Catalysts. Effect of Rare-Earth Content

Alumina-lantana (2.5, 5, 7.5 and 10 wt% La) mixed oxides of suitable texture to be applied as supports of catalysts for hydrodesulfurization of FCC naphtha-range oil-derived distillates were prepared by rare-earth pore-filling impregnation through corresponding nitrate. Co, Mo and P were deposited on binary carriers by one-pot simultaneous impregnation method used during commercial hydrotreating catalysts preparation. Materials were characterized by N2 physisorption, XRD, SEM–EDS, adsorbed CO2 FTIR (basicity measurements), Raman and UV–vis spectroscopies. Sulfided catalysts were studied by chemical composition (EDAX) and HR-TEM. In general, amount and strength of surface basic sites increased with rare-earth content in binary carriers at 5 wt% and higher. Deposited molybdates dispersion augmented with lanthanum content in carriers. However, progressively increasing rare-earth loading on supports was detrimental on gas-phase thiophene HDS (523–563 K, steady-state fixed-bed plug-flow reactor operating at atmospheric pressure). Hardly sulfidable tetrahedral Mo species could be originated by decomposition of heteropolymolybdates originally present in one-pot acidic (pH ~ 1.9) Co–Mo–P solutions by impregnating at basic conditions in pores of La-modified carriers. At isoconversion (~ 10%) rare-earth containing sulfided CoMo catalysts had decreased yield to fully saturated n-butane as to the material supported on pristine alumina.

Effect of eggshell membrane as porogen on the physicochemical structure and protease immobilization of chitosan-based macroparticles

Chitosan-based macroparticle is a common carrier for enzyme immobilization applied in food industry. Driven by the requirement of large carrier pores for the biomacromolecular substrates such as protein, the eggshell membrane powder (ESMP) was employed as multifunctional porogen to improve the physicochemical structure of chitosan-based macroparticles. The prepared macroparticles were characterized by SEM, XRD, FTIR, Raman spectroscopy, nitrogen adsorption-desorption isotherms, and thermogravimetric analysis. The results showed that an increase of ESMP percentage could improve the porosity of macro holes in macroparticles, and it also enlarged the size of mesopores. Moreover, the ESMP significantly increased (P < 0.05) the amount of papain immobilization, whereas the specific activity of immobilized papain achieved a maximum value of 871.95 U/mg at CSESM2 and then declined with the increase of ESMP. Therefore, the inclusion of 20 % ESMP in chitosan-based macroparticles gave the highest activity of its immobilized protease.

Pt/Ga-SBA-15 composites synthesis and characterization

Pt (0.5, 1 and 1.5 wt%) was impregnated by incipient wetness on SBA-15 and corresponding Ga-modified (3, 5, 10 and 20 wt%) composites. Gallium nitrate was incorporated directly during the mesoporous siliceous network synthesis. Materials were characterized by N2 physisorption, X-ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. SBA-15 had surface area greater than 800 m²/g that decreased by Ga incorporation in binary materials. It seemed that tetrahedral gallium was well-incorporated into mesoporous silica walls. Pt dispersion slightly diminished (as to that on SBA-15) by augmenting Ga concentration in composites. Corresponding pore size maxima shifted to lower diameters (as to that of non-impregnated supports) after platinum loading suggesting Pt crystals inside pores of SBA-15 and Ga-modified carriers. Large cubic platinum crystals were observed over all prepared materials probably due to sintering (during calcining at 500 °C) of metallic particles weakly interacting with the carriers surface. After materials annealing (500 °C under static air) metallic platinum was evidenced (by XRD) pointing out to noble metal reduction that could be facilitated by decomposition of organic remains from Si alkoxide used during supports synthesis which presence was ascertained by FTIR.

Mejorando la dispersión de platino en SBA-15 mediante adición de titanio

Pt (1 and 1.5 wt%) was impregnated on SBA-15 and corresponding Ti-modified composites at different TiO2 contents (3, 5, 10 and 20 wt%). Materials were characterized by N2 physisorption, X-ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. SBA-15 had surface area greater than 800 m²/g that progressively decreased with increasing TiO2 content in binary materials. Very different hydrolysis rate of Ti and Si alkoxides could provoke encapsulation of segregated titania domains in SBA-15 structure. Highly reactive titanium butoxide hydrolysis-condensation could take place before reactions corresponding to tetraethyl orthosilicate. Pt dispersion clearly augmented with Ti concentration in composites where numerous tiny noble metal particles were observed on titania domains surface. Also, corresponding pore size maxima shifted to lower diameters (as to that of non-impregnated supports) after platinum loading suggested metallic crystals inside pores of Ti-modified carriers. However, some large cubic platinum crystals were also observed suggesting &nbsp;sintering (during calcining at 500 °C) of metallic particles weakly interacting with SBA-15 component. After materials annealing under air metallic platinum was evidenced (by XRD) pointing out to noble metal reduction during decomposition of organics from Ti and Si alkoxides used during carriers synthesis which presence was ascertained by FTIR.

Development of Two novel silica based symmetric triazine-ring opening N-donor ligands functional adsorbents for highly efficient separation of palladium from HNO3 solution.

The synthesis and characterization of two novel symmetric triazine-ring opening ligands CA-MP (pyridine derivative)/CA-BOPhen (1,10-phenanthroline derivative) functionalized SiO2-P (P = Polymer) adsorbents for separation of Pd(II) from HNO3 solutions are presented. SEM, N2 adsorption/desorption isotherms, TGA and EDS spectroscopy characterization results showed that CA-MP and CA-BOPhen were successfully introduced into the pores of SiO2-P carrier via physical intermolecular interactions. CA-MP@SiO2-P and CA-BOPhen@SiO2-P show high efficiency, high selectivity, extremely fast adsorption rates towards Pd(II) over 19 typical fission or corrosion products in HNO3 solution. The distribution coefficient Kd values of CA-MP@SiO2-P and CA-BOPhen@SiO2-P are up to 206.5 and 205.7 cm3/g, respectively, within 10-15 min of contact time in 0.4 M HNO3. The adsorption capacities of them to Pd(II) were determined to be 0.36 mmol/g and 0.23 mmol/g, respectively. The fast adsorption rates and high selectivity of two adsorbents towards Pd(II) were related to the formation of the highly preorganized complex [Pd(NO3)(L)]+ (L = CA-MP or CA-BOPhen). These results demonstrate that CA-MP@SiO2-P and CA-BOPhen@SiO2-P possess great potential for highly efficient removal of Pd(II) from highly active liquid waste (HLW).

Dibenzothiophene Hydrodesulfurization over P-CoMo on Sol-Gel Alumina Modified by La Addition. Effect of Rare-Earth Content

Alumina-lanthana (La at 1, 3, or 5 wt%) supports were prepared by sol-gel from Al alkoxide sol where La(NO3)3 was added. Annealed (550 °C) xerogels were characterized by N2 physisorption, thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy- energy dispersive spectroscopy (SEM-EDS), CO2-adsorption studied in IR region, Raman and ultraviolet-vis (UV-vis) spectroscopies. The texture of amorphous binary matrices of high La dispersion was adequate to applications in catalysts for middle distillates hydrodesulfurization (HDS). Generally, the amount and strength of surface basic sites increased with La content in solids. Mo (at 2.8 at. nm−2) and Co (at Co/(Co+Mo) = 0.3) were deposited over carriers by one-pot simultaneous impregnation in the presence of PO43− (P2O5/(NiO+MoO3) = 0.2 mass ratio). Calcined (400 °C) Co-Mo-P impregnated precursors had decreased basicity as to that of corresponding carriers, suggesting strong La-deposited species interaction. As La content in carriers increased Mo=O Raman stretching vibrations shifted to lower wave-numbers (949 to 935 cm−1) suggesting octahedral molybdates coordination change to tetrahedral. Although La at the lowest concentration (1 wt%) enhanced dibenzothiophene, HDS (~38% higher as to the Al2O3-supported formulation) desulfurization was significantly diminished at augmented content. Presence of hardly sulfidable tetrahedral Mo originated during impregnation at basic conditions in pores of La-modified carriers seemed to dictate observed behavior. Rare earth content in formulations enhanced selectivity to biphenyl.

Room-temperature hydrogen sulfide removal with zinc oxide nanoparticle/molecular sieve prepared by melt infiltration

Melt infiltration was used to prepare supported zinc oxide (ZnO) adsorbents for hydrogen sulfide (H2S) removal at room temperature, with three molecular sieves (MCM-41, SBA-15, and MCM-48) as carriers. The physical/chemical properties and the performance of these adsorbents were compared with those prepared by impregnation. Low- and wide-angle X-ray diffraction, nitrogen adsorption and transmission electron microscopy characterizations revealed that because precursor penetrated into the pores of carrier by capillary force, melt infiltration can yield more evenly dispersed ZnO in the pores of molecular sieve compared with the impregnation. Based on the breakthrough capacity, the best ZnO loading contents were 20 wt% on MCM-41 and SBA-15, and 30 wt% on MCM-48, and their corresponding utilization ration reached 69.8%, 52.2%, and 45.1%. With the same loading, the utilization ration of adsorbents prepared by impregnation was only 26.8%, 38.2% and 28.3%. Breakthrough tests and multiple adsorption/regeneration cycles showed that adsorbents with a large specific surface area, large pore size, and high strength were favorable. However, carrier with a small pore size and high strength could benefit much more from the melt infiltration.

Manufacturing of Pharmaceuticals by Impregnation of an Active Pharmaceutical Ingredient onto a Mesoporous Carrier: Impact of Solvent and Loading

In this study, an active pharmaceutical ingredient (API) was impregnated onto a mesoporous carrier (excipient) in a fluidized bed. Impregnating APIs in porous carriers has the potential to simplify the drug substance development process and leads to the elimination of the blending and granulation unit operations. Impregnation and drying occur simultaneously in fluidized-bed impregnation, and this method precludes several challenges encountered in other impregnation methods. Furthermore, the process ensures a uniform distribution of APIs within the porous carriers. This method also allows for a variety of solvents to be used in the impregnation. Using a batch fluidized-bed dryer, impregnation of acetaminophen (APAP) onto a magnesium/aluminum metasilicate (Neusilin R) was studied. Water and methanol were used as transport solvents to impregnate different loadings (w/w) of APAP, namely, ranging from 24 to 0.1%. Uniformity tests indicated that APAP loadings of all impregnated products are close to their target loadings across carrier size classes. Tests before and after impregnation showed that there were no changes observed in the physical properties of the carrier, such as particle size, compressibility, and flow properties. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis performed on the samples indicated that the low loadings APAP was present in the carrier pores in its amorphous state. At high loadings, we observed that APAP was mainly present in its amorphous state, however, some degree of crystallinity was observed. Lastly, dissolution tests on the impregnated product showed enhanced dissolution rates in acidic media, and comparable dissolution rate in de-ionized (DI) water, compared to the pure drug crystals. Our results show that the method of fluidized-bed impregnation yields a product with high uniformity and overcomes several challenges presented by traditional physical blends.

Controlling drug release from mesoporous silica through an amorphous, nanoconfined 1-tetradecanol layer

Mesoporous silica materials are promising nano-carriers for drug delivery systems. Even though there are many strategies for controlling the drug release kinetics, these must be adapted through trial and error on a case-by-case basis. Here we explore the possibility of tailoring the release kinetics of hydrophilic, water soluble therapeutic agents from mesoporous silica through addition of a hydrophobic excipient, 1-tetradecanol. In vitro drug release experiments performed at 37 °C, in phosphate buffer solution (pH 7.4) show that the addition of tetradecanol yields slower drug release kinetics, which was correlated with the presence of a liquid fatty alcohol interfacial layer. The layer mass is 11–23 wt.% of the metoprolol-loaded silica sample, and it causes up to 1.6 times decrease of initial release rate with respect to materials without the fatty alcohol. This effect does not depend of carrier pore arrangement, being noticed for both hexagonal MCM-41 and cubic KIT-5 mesoporous silica. The toxicity of tetradecanol-containing materials was evaluated by formazan-based viability assay on Opossum kidney epithelial cell line, and no significant toxicity was observed.

Modification, characterization and investigations of key factors controlling the transport of modified nano zero-valent iron (nZVI) in porous media

ABSTRACTEnhancement of nano zero-valent iron (nZVI) stability and transport in the subsurface environment is important for in situ degradation of contaminants. Various biodegradable dispersants (poly (acrylic acid) (PAA), Tween 20 and Reetha Extracts) have been tested to evaluate their effectiveness in this regard. Application of dispersants during the synthesis of nZVI have positively affected the reduction in particle size. The transport capacity in terms of fraction elution at different pore water velocities and collector grain size (filter media) was analyzed using correlation equation for the filtration model by Rajagopalan and Tien (RT model). At a surfactant concentration of 5% for PAA, Tween 20 and Reetha (Sapindus trifoliata) extracts, the lowest particle size and the highest zeta potential achieved are 8.67 nm and −55.29 mV, 75.24 nm and −62.68 mV, 61.6 nm and −37.82 mV, respectively. The trend of colloidal stability by The Derjaguin—Landau—Verwey—Overbeek (DLVO) Theory model for PAA and Reetha applied concentration was 3% > 4% > 5% > 2% > 1% > 0%. For Tween 20, modified nZVI particle shows a higher repulsive force with increasing Tween 20 concentration. Results indicated that some mechanisms such as aggregation, ripening and surface modification with different carrier pore water velocities had a considerable impact on nZVI retention in porous media. The results indicate that natural surfactant like Reetha extracts exhibits an alternative potential capacity for nZVI modification in comparison with synthetic surfactants (PAA and Tween 20).

In Vitro Dissolution, Cellular Membrane Permeability, and Anti-Inflammatory Response of Resveratrol-Encapsulated Mesoporous Silica Nanoparticles.

Sizing drugs down to the submicron and nanometer scale using nanoparticles has been extensively used in pharmaceutical industries to overcome the poor aqueous solubility of potential therapeutic agents. Here, we report the encapsulation and release of resveratrol, a promising anti-inflammatory and anticancer nutraceutical, from the mesopores of MCM-48-type silica nanospheres of various particle sizes, i.e., 90, 150, and 300 nm. Furthermore, the influence of the carrier pore size on drug solubility was also evaluated (3.5 vs 7 nm). From our results, it is observed that the saturated solubility could depend not only on the pore size but also on the particle size of the nanocarriers. Moreover, with our resveratrol-mesoporous silica nanoparticles formulation, we have observed that the permeability of resveratrol encapsulated in MCM-48 nanoparticles (90 nm) can be enhanced compared to a resveratrol suspension when tested through the human colon carcinoma cell monolayer (Caco-2). Using an in vitro NF-κB assay, we showed that resveratrol encapsulation did not alter its bioactivity and, at lower concentration, i.e., 5 μg mL-1, resveratrol encapsulation provided higher anti-inflammatory activity compared to both resveratrol suspension and solution. All combined, the reported results clearly highlight the potential of small size mesoporous silica nanoparticles as next generation nanocarriers for hydrophobic drugs and nutraceuticals.