Ethanol Impregnation Research Articles

Synthesis and characterization of Fe3O4@MIL-100 nanoparticles as an SSI-assisted drug carrier

In this study, core–shell structured Fe3O4@MIL-100 nanoparticles were synthesized through an in-situ growth method. The resulting magnetic composite exhibited significant magnetic responsivity, with a magnetization saturation (Ms) of 37.24 emu/g and a magnetocaloric temperature rise of 42.1 ℃ within 6 min at 20 A. Supercritical solution impregnation (SSI) technology was used for CUR loading, achieving an outstanding drug loading content of 4.36 wt% compared to ethanol impregnation. These results show the potential of the present magnetic materials with SSI process in biomedical applications.

Cold plasma and ethanol coupling-activated Ni/MCM-41 catalysts with highly stability and activity for dry reforming of methane

The deficiency of hydroxyl in ethanol impregnation method for dry reforming of methane (DRM) resulted in poor activity and stability. A new cold H2-plasma activation technique was proposed to enhance the performance of ethanol impregnation catalyst. Nickel catalysts (NM-EA-PH) supported on MCM-41 were prepared and activated by cold H2-plasma. And its structure and catalytic performances were evaluated. The BET results revealed that the addition of ethanol significantly reduced the effect of plasma on the carrier MCM-41. The ethanol-coupled H2-plasma treatment effectively reduced the nickel particles, and the particle size of NM-EA-PH catalyst was only 7.4 nm, which was 10.8 nm smaller than that of MCM-41 loaded nickel catalyst (NM-C) prepared by conventional impregnation method and activated by conventional roasting (18.2 nm), and enhanced Ni-carrier interaction. Consequently, the catalyst NM-EA-PH had high initial activity with excellent stability, with a low carbon deposition (1.72%) after 20 h of continuous reaction at 700 °C, which was 25.57% less than that of NM-C (27.29%) catalyst. This study introduces a new approach by exploring the effect of plasma-assisted ethanol impregnation method on developing high-performance catalysts.

Preparation of curcumol-loaded magnetic metal-organic framework using supercritical solution impregnation process

A metal-organic frameworks (MOFs)-based drug delivery system was prepared by supercritical solution impregnation (SSI) technology. Firstly, core-shell structured Fe3O4@UiO-66 composite was synthesized by in situ growth of MOFs layers on the surface of carboxy-functionalized Fe3O4. The composite exhibited superparamagnetic properties with a magnetization saturation of 5.51 emu/g, allowing magnetic targeting and MR imaging along with effective drug loading and controlled release. A hydrophobic anti-cancer drug, curcumol (CUR) was encapsulated into the synthesized composite using the SSI process and ethanol impregnation. The effects of impregnating solvent, impregnation time, impregnation temperature and impregnation pressure on the drug loading content were investigated. In SSI process, the drug load reached impregnation equilibrium within 2 h. In the range of pressure 10–20 MPa and temperature 40–60 °C, the drug loading content was varied from 1.09 wt% to 5.72 wt% by adjusting the impregnation conditions. The optimal impregnation conditions were 50 °C and 20 MPa. SSI was more efficient and faster compared to conventional ethanol impregnation, and the final product can be obtained without further purification. In in vitro drug release experiment, Fe3O4@UiO-66 exhibited a sustained controlled drug release for up to 36 h. Overall, SSI technology proves to be a promising strategy to maximize the drug loading capacity of Fe3O4@UiO-66.

Novel nanowire self-assembled hierarchical CeO2 microspheres loaded with nickel-based catalysts for hydrogen production from steam reforming of glycerol

The nickel-based catalysts with shape-specific CeO2 nanocrystals (hierarchical and spheres) and adjustable impregnation solvents were successfully synthesized. The synthesized Ni-CeO2 catalysts were used as the model catalyst to study the structure-dependent catalytic behavior and catalytic reaction mechanism for hydrogen production from glycerol steam reforming (GSR). Ni/CeO2-HE with the hierarchical structure and ethanol impregnation solvent obtained the strongest metal-support interaction. Electron effects because of the strong interaction between nickel and cerium dioxide promoted the formation of reducible nickel species. High nickel reduction and nickel dispersion contributed to the maximum active nickel exposure surface area, thus Ni/CeO2-HE exhibited superior glycerol conversion than other catalysts. The abundant oxygen vacancies generated due to strong Ni-CeO2 interaction facilitated the dissociation of water, thereby achieving a high yield of H2 for Ni/CeO2-HE. As a comparison, Ni/CeO2 and Ni/CeO2-E showed relatively poor catalytic activity due to lower exposed specific surface area and oxygen vacancy concentration. Moreover, the strong oxygen storage-release ability (CO-OSCC) promoted the oxidation of carbon deposition on Ni/CeO2-HE. As a result, Ni/CeO2-HE obtained good catalytic stability with no inactivation within 25 h. The study of the modulation role of Ni-CeO2 interaction on catalytic behavior can provide valuable guidelines for designing efficient catalysts for GSR.

Effect of coloured TiO2 with different oxygen vacancy concentrations on the photocatalytic oxidation of gaseous mercury

ABSTRACT To develop a facile method to prepare an efficient photocatalyst for removing element Hg0 with highly toxic, the coloured TiO2 were prepared through calcining ethanol impregnation method at mild temperature, which is economical and simple and conducive to large-scale industrial promotion. The as-prepared samples were characterised by XRD, SEM, TEM, BET, XPS, EPR, UV-vis etc. and evaluated for the effect of oxygen vacancy concentration on the photocatalytic activity through the removal of zero-valent (Hg0) mercury. The photocatalytic mercury removal efficiency of T200 reached 62.3%, 3 times higher than that of P25. And the related mechanism explanation is proved.

A facile modification of cation exchange resin by nano-sized goethite for enhanced Cr(VI) removal from water

ABSTRACT A novel macroporous strong acidic cation exchange resin (D001) modified by nano-sized goethite (nFeOOH@D001) was fabricated by using a facile ethanol dispersion and impregnation method, and its efficiency for Cr(VI) removal was tested thereafter. Due to the dispersing effect of ethanol, FeOOH particles of 20–150 nm were coated on the D001 surfaces. The nFeOOH@D001 obtained a Cr(VI) removal efficiency and capacity of 80.2% and 7.4 mg/g respectively, 5 times and 8 times higher than that of the pristine D001. The Cr(VI) removal by nFeOOH@D001 followed the pseudo second-order kinetics and the Langmuir adsorption model. Column experiments also demonstrated that the nFeOOH@D001 exhibited a much better ability to remove Cr(VI) as compared to the D001. Additionally, the nFeOOH@D001 showed a potential for reusability and renewability. The adsorbed nFeOOH@D001 could be easily desorbed by 0.1 M acetic acid and a reuse efficiency of 92.7% could be maintained after 4 desorption–adsorption cycles. The used nFeOOH@D001 could be eluted by 0.1 M HCl to remove nFeOOH, and the renewed D001 could be recoated by nFeOOH and achieved a regeneration rate of 97.8% for Cr(VI) removal. The above results indicated that nano-sized goethite modification is a promising method to endow D001 with the ability to remove Cr(VI) from water.

Maximizing paraffin to olefin ratio employing simulated nitrogen-rich syngas via Fischer-Tropsch process over Co3O4/SiO2 catalysts

The optimization of cobalt oxide (Co3O4) loading on silica for the low-temperature Fischer-Tropsch (LTFT) synthesis process employing simulated nitrogen-rich syngas (50 vol%) to produce highly paraffinic biodiesel is studied. Four different amounts of Co3O4 varying from 15 to 36 wt% were loaded on silica in order to examine the catalytic performance of Co/SiO2 catalysts. The supported catalysts were characterized using XRF, nitrogen physisorption, XRD, TPR, DRIFT and SEM fixed with EDS analysis. The performances of the catalysts were examined in a single channel fixed bed reactor employing simulated nitrogen-rich syngas (CO:H2:N2 = 17:33:50 vol%). The reactor was operated at P = 20 bar, T = 237 °C and WHSV = 3.0 Nl/h.gcat. The active site concentration was maximized by (i) utilizing all the available surface area of the sphere's porous support, (ii) using ethanolic impregnation solution to hinder sintering of Co3O4 phases due to presence of ethoxyl groups, and (iii) connecting oxide crystallites to the neighbouring pores by increasing the active metal content. As a result, the production of heavy hydrocarbons per unit of time was maximized with 36 wt% cobalt loading on silica (CO conversion and C5+ selectivity were 87.65 and 81.78 mol%, respectively, and also paraffin: olefin ratio was 98:2).

One-Step Synthesis of Highly Active and Stable Ni–ZrOx for Dry Reforming of Methane

A series of Ni-Zr catalysts with different Ni loadings were prepared by a novel one-step urea hydrolysis method, and compared to 10Ni/ZrO2 catalyst prepared by ethanol impregnation method. The cata...

Cork powder as a new natural and sustainable fining agent to reduce negative volatile phenols in red wine

In red winemaking, especially those aged in wood barrels, the contamination and growth ofDekkera/Brettanomycesyeasts results in the formation of 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG). These volatile phenols (VPs) are responsible for negative aromatic notes like horsy, barnyard, smoky and medicine, decreasing significantly red quality and its commercial value. In this work, cork powder waste was especially prepared and used to remove these negative volatile phenols (4-EP and 4-EG) from spiked red wine. The optimisation of cork powder performance by removal of dichloromethane and ethanol cork extractives, air removal and ethanol impregnation, allowed to obtain 41 to 62% of 4-ethylphenol and 50 to 53% of 4-ethylguaiacol removal from VPs spiked red wine applied at 250 g/hL. There was no significant impact on phenolic acids and monomeric anthocyanins, although being observed a decrease in the headspace aroma abundance (40%). This optimised cork powder allowed to decrease significantly the wine negative phenolic character, bitterness and astringency, recovering the positive fruity and floral sensory attributes. Results show that optimised cork powder can be a good solution for VPs removal, presenting a great potential to be a new oenological fining agent, contributing to the wine industry sustainability.

A Simple Method To Improve Cork Powder Waste Adsorption Properties: Valorization as a New Sustainable Wine Fining Agent

Cork powder, an abundant, natural, and cheap byproduct of the cork stopper industry was explored, either in its natural form or after improvement of their adsorption properties by simple physicochemical treatments, as a new sustainable wine fining agent for removing negative volatile phenols (VPs), responsible for one of the most frequent and widespread aroma defects in red wine known as “Brett character”. Cork adsorptive performance improvement by removal of cork extractives, air removal, and ethanol impregnation allowed us to obtain 41% to 62% of 4-ethylphenol (4-EP) and 50% to 53% of 4-ethylguaiacol (4-EG) removal from red wine. Performance of the optimized cork powder on removing the negative sensory phenolic defect and recovery of the positive fruity and floral sensory attributes was not significantly different from activated carbon and chitosan, two of the most efficient treatments currently available. Optimized cork powder can be a good solution for VPs removal without impacting negatively on wine ...

Insight into structural role of 2D/3D mesoporous silicon in catalysis of magnesium sulfite oxidation

Sulfite oxidation is a key step in wet flue gas desulfurization. Cobalt was used as the active species, and the catalysts supported using three silicon mesoporous molecular sieves (SMMSs) in two (Co-MCM-41, Co-SBA-15) and three (Co-KIT-6) dimensions were fabricated through ethanol impregnation. Compared with the noncatalytic oxidation rate (0.009 mmol L−1 s−1), the catalytic oxidation rate reached 0.078, 0.063, and 0.048 mmol L−1 s−1 in the presence of Co-SBA-15, Co-KIT-6, and Co-MCM-41, respectively. Their physic-chemical properties were characterized to reveal the role of structure in this catalytic process through N2 adsorption–desorption, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, inductively coupled plasma optical emission spectrometry, H2-pulse adsorption, temperature-programmed reduction, transmission electron microscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy mapping. The structural effect on the catalytic activity of cobalt nanoparticles was reflected by varying the dispersion and morphology of active cobalt, the facility of diffusion of reactants, and the binding force between the active cobalt and supports. The kinetics of MgSO3 catalytic oxidation by SMMS catalysts were investigated, indicating that the reaction was controlled by the internal diffusion of oxygen. The results suggest the feasibility of reclaiming the byproduct and downsizing the oxidation pool for magnesia desulfurization.

Fe–Ce Mixed Oxides Supported on Carbon Nanotubes for Simultaneous Removal of NO and Hg0 in Flue Gas

Developing simultaneous removal technology of NOx and Hg0 in flue gas is highly desirable but remains challenging. Multiwalled carbon nanotube supported Fe–Ce mixed oxide nanoparticles (Fe(2)Ce(0.5)Ox/MWCNTs) were prepared using the ethanol impregnation method for DeNOx and Hg0 removal. The NO and Hg0 removal efficiencies over catalyst reached to 99.1% and 88.9% at 240 °C and a space velocity of 30 000 h–1. The Fe–Ce mixed oxides supported both inside and outside of MWCNTs in highly dispersed form with particle size of 3–5 nm. The Ce4+ existed on MWCNTs in two forms, some of which are the fluorite-like crystal CeO2; the other portion of Ce4+ entered the spinel structure of γ-Fe2O3 and led to the distortion of the γ-Fe2O3 lattice. Furthermore, it is evident that the chemisorbed oxygen content and oxidation activity of catalysts increased dramatically after Ce doping, which could be attributed to the excellent NH3-SCR and Hg0 removal performance.

Influence of carbon-functional groups with less hydrophilicity on a TiO 2 photocatalyst for removing low-level elemental mercury

Abstract A carbon-containing titanium dioxide (C-TiO 2 ) photocatalyst was prepared via ethanol impregnation using commercial Ishihara ST-01 TiO 2 powder as the precursor. Scanning Electron Microscopy and X-ray Diffractometry results indicated that raw ST-01 and C-TiO 2 had similarly globular shapes and presented in anatase phase. N 2 adsorption isotherms suggested that carbon impregnated on the TiO 2 surface could slightly reduce the total surface area and pore volume. X-ray Photoelectron Spectroscopy and Fourier Transform Infrared Spectroscopy examinations further supported the formation of various C-functional groups on the C-TiO 2 surface. Removal of low-concentration Hg 0 by raw and C-TiO 2 was enhanced with increasing O 2 concentration. Furthermore, because the existence of C-functional groups on the C-TiO 2 surface, the photoinduced hydrophilicity resulted from light irradiation appears to decrease, causing less adsorption competition from H 2 O for Hg 0 adsorption at higher temperature. The reemission of adsorbed Hg species could thus be significantly decreased by carbon impregnation.

Simple ethanol impregnation treatment can enhance photocatalytic activity of TiO2 nanoparticles under visible-light irradiation.

Doping with impurities as well as introducing oxygen vacancies has been recognized as an important means to enhance photocatalytic activity of TiO2 under visible-light irradiation. Here we report that simple ethanol impregnation followed with mild heat treatment (150-400 °C) can color TiO2 nanoparticles and enhance visible-light photocatalytic activity of the material. The coloration and photocatalytic activity for β-naphthol and rhodamine B (RhB) degradation were observed to be dependent on heat-treatment temperature, and the highest activity as well as the most coloration was obtained at temperatures around 200 to 250 °C. Comprehensive analyses based on X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) investigations as well as first-principle density functional calculation suggest that the simple ethanol impregnation treatment leads to the generation of oxygen vacancy on TiO2 surface which should be responsible for the coloration and enhanced photocatalytic activity.

Comparison of the preparation methods for a highly efficient CuO/TiO2 photocatalyst for hydrogen generation from water

Efficient and visible-light responsive CuO/TiO2 photocatalysts were fabricated by six methods: simple wet impregnation (SWI), ethanol impregnation (EI), stepwise impregnation (SI), in situ sol–gel (SG), chemical adsorption decomposition (CAD), and composite precipitation (CP). The prepared CuO/TiO2 composites were characterized using X-ray diffraction, nitrogen adsorption desorption isotherms, transmission electron microscopy, UV–Vis diffuse reflectance spectra, and H2-temperature programmed reduction. Due to the different preparation processes, the hydrogen evolution rate from water splitting on the as-prepared CuO/TiO2 nanocomposites was recorded. The results showed that the photocatalytic hydrogen evolution rate decreased in the sequence of CAD sample > CP sample > EI sample > SWI sample > SI sample > SG sample. The hydrogen evolution rate of the CAD sample was proved to be the highest among the samples and reached 3155.7 μmol/(g·h), which was 2.46 times larger than that of SG sample. In addition, the stability of the CAD sample and the EI sample was compared. The addition of copper could efficiently suppress the recombination of electron/hole pairs in titanium dioxide, improve the transfer of interfacial charge, enhance visible-light adsorption and provide plentiful photocatalytic reaction active sites.

Synthesis of Highly Dispersed Ruthenium Nanoparticles Supported on Activated Carbon via Supercritical Fluid Deposition

Highly dispersed ruthenium (Ru) nanoparticles supported on activated carbon (AC) were controllably synthesized by supercritical fluid deposition (SFD). The Ru nanoparticles prepared by SFD presented a smaller mean particle size than particles prepared by the ethanol impregnation method. The effects of temperature, pressure, and Ru loading on catalyst preparation were systematically investigated. As any one of above parameters increased, Ru mean particle sizes always decreased first and then increased. The smallest mean particle size (1.6 nm) was obtained at Ru loading of 2%, 45 °C, and 10 MPa. On the scale of Ru mean particle size from 1.6 to 3.9 nm, the catalysts with smaller Ru mean particle size presented higher catalytic activity. The interactions between the Ru precursor and AC were characterized by TG–MS, TPR, and FTIR spectroscopy. The results obtained have revealed the reduction of the carbonyl (C═O) in Ru precursors after depositing on AC with the aid of SCCO2.

Ordered mesoporous CoFe2O4 nanoparticles: molten-salt-assisted rapid nanocasting synthesis and the effects of calcining heating rate

Ordered mesoporous CoFe2O4 magnetic nanoparticles were successfully synthesized via a novel molten-salt-assisted nanocasting process. Highly ordered mesostructures were negatively replicated from the mesoporous silica template of SBA-15. The time that the whole synthetic process took was significantly shortened by a facile molten-salt mixing pretreatment, instead of conventionally used ethanol impregnation of the precursors. Mesoporous bimetal oxide CoFe2O4 nanoparticles of high quality were eventually obtained, while the total processing time was reduced by dozens of hours. In addition, effects of the rarely investigated factor, calcining heating rate were studied systematically. XRD and TEM characterization indicates that both the phase purity and crystallinity of products fell and the highly ordered mesostructures were destroyed gradually as heating rate accelerated. Further, both the specific surface areas and the magnetic properties of as-synthesized mesoporous CoFe2O4 nanoparticles dropped when quicker calcining heating rates were used. Therefore, in order to obtain highly ordered and crystalline mesoporous CoFe2O4 nanoparticles of large specific surface area (150.20 m2 g−1) and saturation magnetization (69.07 emu g−1), utilizing relatively low calcining heating rates (i.e. no quicker than 3 °C min−1) was recommended. Additionally, it is believed that our research findings would help industrial applications of mesoporous CoFe2O4 nanoparticles in many fields like magnetic recording, concerted catalysts, electrode materials and drug delivery.

Effect of preparation method on nature and distribution of vanadium species in vanadium-based hexagonal mesoporous silica catalysts: Impact on catalytic behavior in propane ODH

This work reports comparative study of catalytic performance of VO x -HMS catalysts prepared by ethanolic impregnation method and direct synthesis. In order to detailed investigation of vanadium speciation depending on vanadium content and its impact on catalytic behavior in C3–ODH, number of samples in wide range of vanadium content (1–16 wt.%) was prepared by both types of preparation. Prepared catalysts were tested in the oxidative dehydrogenation of propane at 540 °C under different contact times and catalytic results were correlated with physicochemical characteristics of the catalysts examined by XRD, XRF, SEM, N 2 adsorption/desorption isotherms, H 2-TPR and DR-UV–visible spectroscopy. Study led to conclusion, that (i) both monomeric VO x complexes and oligomeric VO x complexes with tetrahedral coordination containing V O V bonds are active and selective catalytic sites for C3–ODH, (ii) active VO x species are characterized by distinct reduction peak in H 2-TPR pattern centered at 570–590 °C, (iii) VO x -HMS vanadosilicates can be directly synthesized under ambient conditions without need for autoclave in wide range of vanadia loading with preservation of good catalytic performance and (iv) the catalytic results in C3-ODH were significantly better for synthesized catalysts compared to impregnated catalysts resulting in three times higher propene productivity of the best synthesized catalyst compared to the best impregnated one under the same reaction conditions. The higher is vanadium loading the more distinct is the difference in catalytic performance of both types of catalysts.

Catalytic behaviour of bifunctional pumice-supported and zeolite/pumice hybrid catalysts for n-pentane hydroisomerization

Abstract A series of phillipsite(zeolite)-rich pumice-based supports with different acidity, Si/Al ratios and textural properties were prepared by acid leaching using hydrochloric acid. The NH 3 -TPD profiles, chemical composition and nitrogen adsorption–desorption isotherms pointed out that textural and acidity properties depend largely on the acidification treatment conditions. Bifunctional catalysts based on platinum supported over protonated pumice have been prepared by ethanol impregnation and tested in n -pentane hydroisomerization. Very low conversions and yields to isopentane have been obtained. The small size of phillipsite channels, lower than the pentane molecule and the intermediate products, may be hindering the access of these molecules to the acidic sites, contributing to their low activity in the target reaction. However, the catalysts constituted by a physical mixture of pumice-supported platinum, with protonated commercial zeolites (H-Mordenite or H-ZSM-5), widely used for light paraffin isomerization, resulted in higher isopentane yields than the bifunctional commercial zeolite-based catalysts. These results are explained by the greater accessibility of metal sites in a wider pore support and by the lesser blocking of the acid surface placed in the zeolite micropores.

Iron oxide modified mesoporous carbons: Physicochemical and catalytic study

Series of iron oxide supported on CMK-1 and CMK-3 materials obtained by impregnation from aqueous or organic media are studied by TPR, XAFS, Moessbauer spectroscopy and methanol decomposition as a catalytic test. More highly dispersed iron oxide particles are obtained using ethanolic impregnation medium, but their dispersion is affected to a low extent by the support pore structure. On the basis of the combined results on the state and reductive phase transformations of the loaded iron oxide particles, more accessible CMK-3 in comparison with CMK-1 pore structure is assumed.