Yifeng Yu

Thin-walled, mesoporous and nitrogen-doped hollow carbon spheres using ionic liquids as precursors

Nitrogen-doped hollow carbon spheres with uniform and tunable morphology can be facilely synthesized by the monodisperse silica-template carbonization followed by hydrofluoric acid etching. The hollow carbon spheres containing 3.2 wt% of nitrogen have a thin wall of 5–12 nm and mesoporous shell structure.

Solid-solid grinding/templating route to magnetically separable nitrogen-doped mesoporous carbon for the removal of Cu2+ ions

N-doped ordered mesoporous carbon materials (NOMC) with 2D hexagonal symmetry structure were synthesized via a facile solid-solid grinding/templating route, in which the ionic liquids (ILs) of 1-cyanoethyl-3-methylimidazolium chloride and SBA-15 were employed as the precursor and hard template, respectively. The as-synthesized NOMC features with a uniform mesoporous size (3.5nm), ropes-like morphology (0.4-1μm in length) and high surface area (803m(2)/g). The quantitative analysis revealed the nitrogen content on the surface of NOMC is 5.5at%. Magnetic iron nanoparticles were successfully embedded into the carbon matrix by introducing iron chloride to the mixture of SBA-15 and ILs during the synthesis process. The NOMC-Fe composite possessed superior adsorption capacity of Cu(2+) ions (23.6mg/g). Kinetic and isothermal analysis demonstrated the strong interactions between Cu(2+) ion and the adsorbent. Furthermore, the composite was magnetically separable from solution under an external magnetic field and thus displayed a superior reusability in the recycling test.

A co-confined carbonization approach to aligned nitrogen-doped mesoporous carbon nanofibers and its application as an adsorbent

Nitrogen-doped carbon nanofibers (MCNFs) with an aligned mesoporous structure were synthesized by a co-confined carbonization method using anodic aluminum oxide (AAO) membrane and tetraethylorthosilicate (TEOS) as co-confined templates and ionic liquids as the precursor. The as-synthesized MCNFs with the diameter of 80-120nm possessed a bulk nitrogen content of 5.3wt% and bimodal mesoporous structure. The nitrogen atoms were mostly bound to the graphitic network in two forms, i.e. pyridinic and pyrrolic nitrogen, providing adsorption sites for acidic gases like SO2 and CO2. Cyclic experiments revealed a considerable stability of MCNFs over 20 runs of SO2 adsorption and 15 runs for CO2 adsorption. The MCNFs also have a preferable adsorption performance for Cd(2+).

Preparation and Characterization of Vanillin Cross-Linked Chitosan Microspheres of Pterostilbene

A vanillin cross-linked chitosan microsphere delivery system was established for stabilization and controlled release of pterostilbene. The prepared microspheres were characterized by SEM images, FT-IR spectra, thermogravimetry, and X-ray diffraction. FT-IR spectra results indicated that chitosan was cross-linked by vanillin successfully. Thermal analysis showed that pterostilbene had been totally incorporated into the microspheres and the encapsulation of pterostilbene decreases the rate of degradation and increases the stability. XRD analysis was conducted to confirm the results of DSC analysis. The release rate of pterostilbene from microspheres in pH 3.6 buffer solution could be up to 58.1 % within 48 h.