查看更多>>摘要：Fluoroquinolones (FQs) in the environment have posed a threat to the ecosystem and human health. The development of efficient and economical materials for the removal of FQs provides an alternative answer to the issue. Herein, calcium and cupric crosslinked alginate nanofibers (SA-Ca/Cu) were prepared by fabrication of electrospun SA nanofibers, followed by crosslinking with CaCl2 and CuCl2. The introduction of Ca~(2+) and Cu~(2+) to crosslink the SA nanofibers not only endows the SA-Ca/Cu nanofibers with water resistance but also provides abundant binding sites to interact with FQs. The SA-Ca/Cu nanofibers are a mesoporous material with the Brunauer-Emmett-Teller surface area of 23.7 m~2 g~(-1), and a pore diameter of 25.5 run. The adsorption isotherms data of SA-Ca/Cu toward FQs were well fitted to the Langmuir model and the kinetics were well described by the general-order model. The maximum adsorption capacities of SA-Ca/Cu toward sparfloxacin, ciprofloxacin, and enrofloxacin were calculated to be 285.0, 338.1, and 375.0 mg g~(-1), respectively. In addition, the adsorption thermodynamics was investigated to help understand the adsorption process. Furthermore, the excellent removal efficiency of the SA-based nanofibers toward FQs from mineral and river water samples, as well as the simulated effluents demonstrates that the natural biomaterial-based mesoporous materials are effective, economical, and potential adsorbents for treating real effluents containing FQs.
查看更多>>摘要：Currently, the direct synthesis of faujasite-type (FAU) zeolites with Si/Al ratios greater than 3 depends on organic or inorganic additives. Here, we report the first additive-free synthesis of faujasite with Si/Al ratios greater than 3 using ultraviolet (UV) light assistance. The obtained zeolite shows excellent catalytic performance comparable to the commercial zeolite Y.
查看更多>>摘要：Three metal ions (Ca~(2+), Mg~(2+), and Zn~(2+)) were found to be successful catalysts to produce high-quality zeolite templated carbon (ZTC), a periodic three-dimensional graphene-like carbon with ordered microporous structure. Their roles in high-quality ZTC formation were studied by characterizing chemical component, surface morphology, structure, and pore properties. Ca~(2+), Mg~(2+), and Zn~(2+) minimize or eliminate the blockage of channels by carbon deposits and non-selective thermal deposition on the external surface of the zeolite particles. The growth temperature was lowered to only 450 °C. Moreover, the formation mechanism of ordered ZTC structure was revealed for the first time.
查看更多>>摘要：Based on the excellent physicochemical properties of mesoporous silica nanoparticles (MSN), the application of MSN in drug delivery has become a popular strategy. However, a wide variety of MSN structures and surface modification affect the drug loading and release, thus affecting the effectiveness of drug delivery system. Therefore, the effects of MSN type, pore structure and modified functional groups on drug release properties were investigated in this paper. A series of MSN was synthesized by sol-gel method, and the mesopore type and pore size were adjusted. Their surfaces were modified by amino groups (NH2) and polydopamine (PDA) to change the surface charge. Anticancer Doxorubicin (DOX) was used as a model drug to study effects of different types of MSN on drug loading and release. MSN with hollow structure had a large inner cavity for DOX loading and tiny pore shell to prevent DOX loss, leading to higher loading capacity. MSN with surface-modified amine was positively charged and processed good pH responsiveness and accelerated DOX release. Thus hexagonal pore MSN-NH2 and MSN-PDA were the anticancer DOX delivery carriers with better combined release performance in terms of pH-responsive performance and sustained release effect. Finally, several kinetic models were measured to fit the in vitro DOX release data and the results showed that release behaviors of different MSNs were more consistent with Korsmeyer-Peppas release kinetic model. All of them were Fick diffusion-controlled except for the second release stage of hollow MSN at pH 7.4, which was non-Fick diffusion release.
查看更多>>摘要：Silica-based UVM-7-type bimodal mesoporous materials with high gadolinium content (∞ ≥ Si/Gd ≥ 13) have been synthesized through a one-pot surfactant-assisted procedure from hydroalcoholic solution using a cationic surfactant as template, and starting from atrane complexes of Gd and Si as inorganic precursors. The novel synthetic pathway developed in the study preserves the UVM-7-type architecture while optimizing the dispersion of the Gd-guest species at the nanoscale and even at atomic level. It has been determined that the number of Gd atoms forming clusters is always less than 10. The behaviour under exposure to ultra-high magnetic fields reveals a significant increase in the transversal relaxivity value when compared with related materials in the bibliography. Their activity as T2 instead of T1 contrast agents is discussed and explained considering the high Gd-dispersion and concentration, nature of the materials as well as due to the high magnetic fields used, typical of MRM studies. The absence of toxicity has been confirmed in preliminary cell cultures 'in vitro' and the degradation of the solids studied under biological conditions. Results suggest that the atrane route could be a suitable synthesis approach for the preparation of Gd containing contrast agents.
查看更多>>摘要：In this study, a facile method was developed to synthesize honeycomb-like nitrogen-doped porous carbon nanospheres encapsulated ultrafine Pd nanoparticles (Pd/H-NPCNs) by a combination of one-step Friedel-Crafts reaction between carbazole and benzylamine monomers and subsequent in-situ impregnation-pyrolysis reduction strategy. The obtained Pd/H-NPCNs are further treated with H2O2 to remove carbon layer from the surface of metal to produce Pd/H-NPCNs-H2O2 catalyst. Owing to the high surface area, hierarchically porous structure and special honeycomb-like morphology, the Pd/H-NPCNs-H2O2 catalyst shows the excellent catalytic performance in the selective hydrogenation of cinnamaldehyde (CAL) under mild reaction conditions and water as a green solvent.
查看更多>>摘要：For tissue engineering applications, porous/biocompatible scaffolds are crucial. Some novel composites, Cu-MOF@PDMS, were fabricated by incorporating Cu-MOF into a PDMS sponge. Then, a layer of chitosan was coated on the Cu-MOF@PDMS sponges by the dip-coating method. The nanocomposites can be benefited by the flexibility characteristic of PDMS, the porosity of the Cu-MOF, and the bactericidal activity of chitosan. Morphological and chemical characterization of the as-obtained materials were investigated using FT-IR, XRD, SEM, EDS mapping, and TEM techniques. The obtained results exhibited that Cu-MOFs and chitosan are attached to the PDMS surface. TEM analysis exhibited the incorporation of Cu-MOF nanoparticles on the PDMS surface. The effect of Cu-MOF and chitosan on the antibacterial activities and cytotoxicity of sponges were also studied. Chitosan enhanced the antibacterial efficacy of the Cu-MOF@PDMS sponges against Staphylococcus aureus and Escherichia coli. The Chitosan@Cu-MOF@PDMS sponge resulted in a marked decrease in the number of viable bacteria cells (>4.5 log_(10) CFU). Biological studies exhibited that the experimented sponges including the Cu-MOF@PDMS and the Chitosan@Cu-MOF@PDMS scaffolds provided proper surfaces for cell adhesion, proliferation, and viability compared with the pure PDMS sponge. Additionally, the obtained results confirmed that the presence of the Cu-MOF and chitosan in the nanocomposites have significant importance in cell attachment and viability. The as-fabricated chitosan-coated Cu-MOF@PDMS sponges are green, biocompatible, and potential scaffolds for antibacterial and tissue engineering applications.
查看更多>>摘要：A 10 wt % NiO on mesoporous Y-zeolite catalyst was studied for vanillin hydrodeoxygenation. Vanillin, having aldehyde, ether and hydroxyl groups is a representative moiety of lignin. Characterization results indicated that alkali-treated zeolites featured mesoporous craters and, after NiO impregnation, yielded a bifunctional acid-hydrogenation catalyst. Mesoporous Y-zeolite allows a greater accessibility of vanillin to Br0nsted acid sites (BAS) giving one order of magnitude higher activity in comparison with pristine Y-zeolite, besides of eliminating methoxy group on the former, but not on the later. Nonetheless, alkali-treatment of Y-zeolite should be done with low alkali concentration to have a balance between craterization and zeolite's crystalline structure. Y-zeolite having both micro- and mesoporous are a more effective choice than untreated Y-zeolite. Methoxy groups can be eliminated through protonation on BAS without aromatic ring hydrogenation, providing aromatic phenolic compounds at low hydrogen consumption.
查看更多>>摘要：Zeolite coated quartz crystal microbalance (QCM) is proposed as an efficient sensor for the detection of ethanol at room temperature. In this work, three zeolites DaY, ZSM-5, and BEA were investigated in order to determine the most efficient adsorbent for ethanol sensing at room temperature. The sensing performances were found to be mostly influenced by the acid site density and the zeolite's pore size. The BEA coated QCM sensor exhibited the best performances with a high relative frequency shift from 9.0 x 10~(-7) to 2 x 10~(-6) for 10 ppm of ethanol. Furthermore, this sensor exhibited fast response and recovery times which makes it a suitable material for the monitoring of ethanol in the air. In addition, the ethanol diffusion order was evaluated using Fickian diffusion law and was found to be the highest for the zeolite BEA. A sensing mechanism was also proposed for the adsorption and desorption of ethanol into zeolites based on unstable protonated dimers, water and diethyle ether resides for the energy-efficient ethanol sensor.
查看更多>>摘要：Two types of zeolite meshes were examined in this study for oil/water separation. The first type involved nanozeolite seeds deposited uniformly on a stainless steel mesh. Second, secondary grown zeolite membranes were synthesized on stainless steel meshes. Both the zeolite meshes were found to be superamphiphilic and underwater superoleophobic. The oil/water separation properties of zeolite membrane meshes were investigated using different types of oil. It was found that the separation efficiency of the mesh was above 99.98%, with the residual rate of oil in water being less than 20 ppm. However, the seed layer mesh did not exhibit good repeatability. Secondary grown zeolite mesh exhibited no significant decline after 50 experiments with diesel and 30 trials with rapeseed oil. The secondary grown zeolite mesh has an average filtration flux of 37.68 m~3/(m~2·h) under gravity. Furthermore, even after storage for two years, the oil/water separation performance of the secondary grown sample was maintained. The study concludes that the secondary grown zeolite membrane mesh has great potential in oil/water separation applications.
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