查看更多>>摘要：Metal-organic frameworks(MOFs)are promising candidates for membrane gas separation because of their high porosity and structural tunability.Although the appropriate size of the pore aperture of MOFs is required depending on the target molecules to separate,pore size control of MOFs occasionally influences crystal growth,preventing the fabrication of dense membranes.In this study,we present a heterobilayer membrane strategy using two isostructural MOFs.First,a MOF Kgm-OPr with fast nucleation rate was fabricated as a seed layer on an Al2O3 substrate,then the layer of Kgm-OMe or Kgm-H,which is isostructural to Kgm-OPr,was prepared on the Kgm-OPr seed layer through secondary growth.In this way,the high-quality membranes which selectively permeate CO2 over N2,CH4,and C2H4 were obtained,although all three MOFs did not form dense membranes when they were used alone.Our result would contribute to the expansion of the family of MOFs applicable to membranes for molecular separation.
查看更多>>摘要：In this work,magnetic Fe3O4@TiO2 nanospheres supported by a mesoporous silica aerogel substrate were synthesized using simple combining procedure of sol-gel and ultrasound assisted reflux technique for photo-catalytic activity.The characteristics study of the as-synthesized ternary nanocomposite showed highly dispersion and covering of the Fe3O4@TiO2 nanoparticles on the silica aerogel.The hydrophobic porous silica aerogel was prepared using industrial diatomite earth(DE)as a silica source by a sol-gel procedure under ambient pressure drying.The specifications results of the resulting silica aerogel revealed a fine particulate morphology with an average size of 26 nm,a low density of about 0.85 g/cm~3 and a good degree of porosity with a BET surface area of 572 m~2/g.In addition,the structural and morphological studies of the prepared Fe3O4@TiO2 also represented the formation of a pure Fe3O4@TiO2 phase with a core shell spherical morphology and an average particle size of 22 nm.The introduction of the Fe3O4@TiO2 on the silica aerogel nanoparticles led to increase the particle size to 38 nm and decrease of BET surface area to 347 m~2/g confirming the formation of Fe3O4@TiO2/silica aerogel nanocomposite.The photocatalytic activity of the prepared ternary nanocomposite was also studied for the removal of tetracycline(TC)as an organic pollutant from water under visible light in details.
查看更多>>摘要：The formation of micro/mesoporous zeolites by treating zeolite crystals with alkaline hydroxides has received a lot of interest,but fundamental understanding is still lacking.Here,we study the reactivity of a crystalline zeolitic material with various alkaline hydroxides,to close this knowledge gap.The use of ex situ and in situ small-angle X-ray scattering has allowed us to determine the reactivity of faujasite(FAU)type zeolite Y at different pH and Si/Al ratio(SAR),with a variety of different organic ammonium hydroxides.Supplemented with ex situ XRD and BET isotherm measurements,we show that the pH of the starting mixture and SAR of the zeolite significantly influence the stability of the microporous structure and the extent of formation of mesoporous material.
查看更多>>摘要：Capacitive deionization(CDI),known as an emerging,environment-friendly,energy-efficient and cost-effective technology,has gained tremendous attention and shown great application potential in brackish water desalination.However,the limited electrical double layer(EDL)capacitance and desalination capacity of conventional carbon-based electrodes seriously affect its practical application.Here,we prepared a flexible,self-supporting,zinc oxide-modified N-doped porous carbon nanofiber membrane(ZnO@N-PCNM)as capacitive deionized electrode materials.The prepared carbon membrane possesses a large specific surface area(488.6 m~2 g~(-1))due to the interconnected and hierarchical multi-layer pores,which can provide more adsorption sites and good electronic/ion conductivity.In addition,benefiting from the high N-doping(10.9%)and the loading of Zn,the prepared ZnO@N-PCNM electrode shows a specific capacitance of 253.62 F g~(-1)in 3 M KOH electrolyte at a scanning rate of 5 mV s"1.As electrode materials for CDI,the ZnO@N-PCNM delivers an outstanding electro-sorption capacities of 32.87 mg g~(-1),23.81 mg g~(-1)and 20.85 mg g~(-1)at a low pressure of 1.8 V for heavy metal ions Pb~(2+),Cu~(2+),and Cd~(2+),respectively.These results mean that the prepared ZnO@N-PCNM membrane has great potential for Hybrid capacitive deionization practical applications.
查看更多>>摘要：The three-dimensional(3D)N/O/S self-doped hierarchical porous carbons(SPI-PC-x)with a"coral"-like geometry structure are successfully synthesized with renewable soy protein isolated(SPI)as the precursor.Draw support from the self-swelling principle of proteins,the SPI hydrogel is fabricated to absorb KOH solution,and thus uniformly distributed KOH not only serves as a built-in template to prevent carbon wall fusion/aggregation,but also acts as an activator to produce plentiful micropores.On the whole,our approach is sustainable because hierarchical porous carbons(PCs)are generated by a one-step pyrolysis process with a very low consumption of KOH.The SPI-PC-0.50 exhibits the gravimetric specific capacitance of 320 F g~(-1)at a current density of 0.5A g~(-1)in the threeelectrode system because of a great specific surface area(SSA)(1914.08 m~2 g~(-1))and a high heteroatom-doping level(16.4 at%).And it achieves the energy density of 8.0 Wh kg~(-1)and 27.0 Wh kg~(-1)in the two-electrode systems with 6 M KOH and 1 M Na2SO4 as electrolytes,respectively.This work provides a theoretical and methodological support for the facile fabrication of 3D heteroatom self-doped PCs with the assistance of SPI gelation and the uniformly distributed activator under the principle of protein self-swelling.
Jason RichardAnthony PhimphachanhAlix Jamet-Fournier
11页
查看更多>>摘要：A versatile approach has been developed to prepare small mesoporous silica particles with simultaneous control of the internal ordered pore structure and the external particle surface.Mixed polyion complex(PIC)micelles are used as silica structure-directing agents: they result from the complexation of a polybase with two polyacid double-hydrophilic block copolymers(DHBC)having either a poly(ethylene oxide)(PEO)based-block or a polyacrylamide(PAM)block.The ionizable block in both DHBC is poly(aerylic acid),which complexes oli-gochitosan to form the core of the electrostatic complex.By varying the architecture of the PEO-based block(linear or comb-shaped)and the synthesis parameters,it is possible to modulate the pore structure from 3D cagelike to 2D-hexagonal and lamellar mesostructures.Replacing a fraction of the PEO-based polymers with DHBC having a polyacrylamide block that has no affinity for silica is shown to affect silica-micelle interactions and material growth.While the PEO chains interact with silica to form the hybrid interface,the PAM chains act as capping agents and control the external surface of the particles.Increasing the relative amount of PAM-based DHBC leads to the formation of small discrete mesoporous silica particles that are reduced in size to 200 nm.The particle size reduction and particle surface stabilization by PAM chains can be explained by considering not only the existence of a mixed corona of PAM and PEO in PIC micelles but also the differentiated solubility of these two neutral blocks induced by silica condensation.Thus,the present strategy allows independent decrease of the particle size and tuning of its pore structure.
查看更多>>摘要：Carbonates present a significantly important area for the research as classical empirical methods applied for sandstones characterization,may easily mislead when applied to carbonates.The impact becomes more protuberant when considering low resistivity pay carbonate formations where Archie's equation may yield higher than actual water saturation values,which,however,underestimate the hydrocarbon reserves.Especially,the bimodal pore sizes distribution makes carbonates extremely complicated for characterization through traditional digital rock physics applications.Unlike sandstone,for a given carbonate sample,it is almost impossible to have pore digital 3D images with minimum elementary volume(REV)to generate a standard pore-network model(PNM)due to the resolution and computational processing power limitations.
查看更多>>摘要：The experiment of Fe-Beta catalysts modified by Ce with incipient wetness impregnation methods was carried out for the selective catalytic reduction of NOx with NH3.The characteristics of the catalyst before and after hydrothermal treatment were evaluated by the changes of the active sites,acid sites and pore structure.The results showed that the conversion from [Fe~(2+)-OX]~+ to [HO-Fe~(3+)-OX]~+ during the reaction of hydrothermal aging promoted the gradual dehydroxylation and condensation of [HO-Fe~(3+)-OX]~+ to generate larger FexOy particles.However,the introduction of Ce slowed down this trend,and [(HO)2-Ce-OX]~+ and [HO-Fe~(3+)-OX]~+ competed with each other in the process of dehydroxylation condensation would not form longer cluster species.The Ce promoted the adsorption and activation of NOx species and more nitrate species in the form of chelated bidentate nitrate,and then improved the formation of NH4NO3,which would remarkably enhance the activity of Ce-Fe-Beta catalyst after hydrothermal aging.
查看更多>>摘要：The combination of organic polymers and inorganic nanoparticles to design intelligent nanocarriers is of great significance for effective delivery of anticancer drugs to tumor cells for therapy.Herein,we have prepared a thermo-responsive micelle as a"gatekeeper"to attach on the surface of mesoporous silica nanoparticle(MSN)through disulfide bonds.DOX was encapsulated in both nanocarriers,resulting in a pH/redox/temperature responsive dual drug delivery platform(DOX@MSN-S2-F127-PCL@DOX,abbreviated as DMSFPD)with high loading capacity and excellent stimuli-responsive performance for cancer therapy.The cumulative release curve in vitro indicated that DOX could be controllably released from DMSFPD.With the elevated temperature at 40 ℃,the uncapping ofF127-PCL250(FP250)micelle from MSN after GSH stimulus and the shrinkage of FP250 micelle caused a fast release of DOX from both MSN and micelle,which greatly increased the drug concentration immediately.The intracellular uptake and cytocompatibility demonstrated that MSN-S2-F127-PCL250(MSFP250)could be efficiently endocytosed and have shown favorable biocompatibility in both normal and tumoral cells.Cytotoxicity results illustrated that DMSFPD could significantly kill different kinds of cancer cells.Therefore,this dual drug delivery capping platform provides a new and promising strategy for cancer therapy.
Bao Quang Gia LeMinh-Huy Dinh DangTrang Thi Thu Nguyen
8页
查看更多>>摘要：Nano metal-organic framework materials are progressively being investigated and used as drug carriers in the biomedical field.Curcumin,an active component derived from turmeric,is commonly utilized in traditional medicine and can support cancer treatment.In this study,ZIF-8 nanomaterial was effectively modified with fluorescence organosilica coating,named ZIF-8@BPMO,to promote bio-interaction and prevent material floc-culation.Powder X-ray diffraction(PXRD),infrared spectroscopy(FT-IR),differential gravimetric analysis(TGA),and isothermal nitrogen adsorption at 77 K were utilized to investigate the synthesized materials.Property analysis revealed that ZIF-8@BPMO nanomaterials had high crystallinity,a large surface area,and a high thermal stability with a particle size of 100 nm.According to the research,this material had high curcumin adsorption capacity of 666 mg g~(-1)for 15 min.Curcumin adsorption on the nanomaterial followed a pseudo-second-order kinetic model and the Freundlich model.Furthermore,thermodynamic investigations demonstrated an endothermic and spontaneous adsorption mechanism.These results indicate that the fluorescent ZIF-8@BPMO nanoparticle is a potential material for bio-applications.
NSTL