Fabrication Of Mesoporous Materials Research Articles

Catalytic Ozonation of Atrazine Enhanced by Mesoporous CeO2: Morphology, Performance and Intermediates

Heterogeneous catalytic ozonation is an alternative approach for the removal of refractory pollutants from water, and the fabrication of mesoporous materials with high dispersibility would enhance the catalytic efficiency. A mesoporous CeO2 was prepared by the nanocasting method with SBA-15 as a hard template, and was investigated in the catalytic ozonation of atrazine. The synthetical CeO2 nanorods have a specific surface area of 95.08 m2/g, a diameter of 10.16 nm, and a spacing of 2.18 nm. The removal rate of atrazine was 85.5%, 64.8%, and 46.4% in the order of catalytic ozonation by synthetical CeO2 > single ozonation > catalytic ozonation by commercial CeO2, respectively. The superior activity of the synthetical CeO2 could be attributed to the well-ordered mesoporous structure, the high surface area, and the redox Ce3+/Ce4+ cycling. Moreover, eight organic intermediates were identified after one minute of catalytic ozonation of atrazine, and the cleavage of the ethylamino group was proposed as the main pathway of atrazine degradation.

Self-templating construction of flower-like mesoporous magnesium silicate composites from sepiolite for high-efficiency adsorption of aflatoxin B1

The rational design and fabrication of mesoporous materials with highly exposed surface area are of great significance to address water pollution problems caused by mycotoxins. In this work, a facile self-templating strategy was developed to construct flower-like mesoporous magnesium silicate composites (MMSCs) by subjecting sepiolite to acid bleaching process, followed by hydrothermal reaction. The effect of hydrothermal time on the microstructures and specific surface areas of MMSCs were investigated, and the possible formation mechanism of MMSCs was proposed. The MMSCs synthesized at hydrothermal time of 12 h showed a well aflatoxin B1 (AFB1) adsorption capacity, and the maximum adsorption capacity, calculated from the Langmuir model, was 21.26 mg/g. The high adsorption capacity was mainly attributed to the synergistic effect of flower morphology and mesoporous structure, providing high surface area, and consequently exposing more available adsorption sites (e.g., Si-O-Mg, Mg-OH, and Si-OH), which favored bonding with AFB1. Density functional theory (DFT) calculations revealed that the mechanisms of AFB1 adsorption onto MMSCs were mainly electron donor-acceptor interaction and hydrogen bonding. The strategy proposed here can provide a new avenue for the design of mesoporous materials with high surface area, and resulting materials are promising adsorbents for adsorption of AFB1.

Additive induced core and corona specific dehydration and ensuing growth and interaction of Pluronic F127 micelles

Pluronic F127 is considered to be the most prominent member amongst Pluronics owing to its uses in the fields of drug delivery and fabrication of mesoporous materials. Though extensive studies were carried out on the phase behavior of this copolymer, the effect of additives on restructuring and growth processes of its micelles is not understood yet. In this manuscript we report DLS, SANS, fluorescence and rheological studies on the effects of NaCl and butan-1-ol on the properties of Pluronic F127 micelles in the aqueous medium. The studies show that corona specific micellar dehydration by NaCl induces inter micellar attraction and consequent formation of micellar clusters. Core specific micellar dehydration by butan-1-ol on the other hand, brings about sphere-to-rod micellar shape transition on approaching the cloud point of copolymer solutions. A room temperature sphere-to-rod shape transition of Pluronic F127 micelles can also be induced in the combined presence of butan-1-ol and NaCl. Observation of such micellar shape transition in aqueous Pluronic F127 system is first of its kind, which can have important bearing with their application in mesoporous structure formation and drug delivery.

Breakthrough and future: nanoscale controls of compositions, morphologies, and mesochannel orientations toward advanced mesoporous materials

Currently, ordered mesoporous materials prepared through the self-assembly of surfactants have attracted growing interests owing to their special properties, including uniform mesopores and a high specific surface area. Here we focus on fine controls of compositions, morphologies, mesochannel orientations which are important factors for design of mesoporous materials with new functionalities. This Review describes our recent progress toward advanced mesoporous materials. Mesoporous materials now include a variety of inorganic-based materials, for example, transition-metal oxides, carbons, inorganic-organic hybrid materials, polymers, and even metals. Mesoporous metals with metallic frameworks can be produced by using surfactant-based synthesis with electrochemical methods. Owing to their metallic frameworks, mesoporous metals with high electroconductivity and high surface areas hold promise for a wide range of potential applications, such as electronic devices, magnetic recording media, and metal catalysts. Fabrication of mesoporous materials with controllable morphologies is also one of the main subjects in this rapidly developing research field. Mesoporous materials in the form of films, spheres, fibers, and tubes have been obtained by various synthetic processes such as evaporation-mediated direct templating (EDIT), spray-dried techniques, and collaboration with hard-templates such as porous anodic alumina and polymer membranes. Furthermore, we have developed several approaches for orientation controls of 1D mesochannels. The macroscopic-scale controls of mesochannels are important for innovative applications such as molecular-scale devices and electrodes with enhanced diffusions of guest species.