Exploring Qualitative and Quantitative Decoration on Amine-Modified Mesoporous Silica for Enhance Adsorption Performances

Using the triblock copolymer Pluronic F127 as a surfactant, tetraethyl orthosilicate (TEOS) as a silica source, and hydroxylamine hydrochloride as an amine source, a group of amines-modified mesoporous silica Santa Barbara Amorph-16 (SBA-16) materials with different template withdrawal methods and amine loading concentrations were prepared through sol-gel conditions. The investigation will provide qualitative and quantitative information on amine-modified SBA-16 decoration with a brief overview of the non-destructive analysis methods for advanced materials as adsorbent candidates. Highly ordered mesostructured amine-modified SBA-16 materials were prepared using high-temperature (or calcination) and solvent extraction de-templating methods. Mesostructured amine-modified SBA-16 has been successfully examined using a Synchrotron Radiation Low-Angle X-ray Diffraction (SR-LXRD) instrument for phase identification, Small-Angle Synchrotron X-rays Scattering (SAXS) for identifying structural changes in a porous material, Fourier Transform Infrared (FTIR) for identifying functional groups, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) elemental analyzer for determining the number of silica, oxygen, and nitrogen elements, and a Specific Surface Area (SSA) analyzer for measuring the specific surface areas. The SR-LXRD and SAXS results demonstrated that the synthesized novel materials were defined unambiguously as a bi-continuous cubic body center Im3m mesostructured. FTIR and SEM-EDS analyses verified that the amine groups were uniformly deposited on the SBA-16 surface. The SSA analyzer results also clarified that the novel materials exhibited ordered and meso-framework amine-modified SBA-16 with a large surface area. Novel materials can be considered high-potential uranium adsorbent candidates. Preliminary adsorption investigations have shown that the amine-modified SBA-16 materials can adsorb uranium in natural seawater showing an uptake capacity of as much as 24.48 mg-U/g-adsorbent

In-situ Observation of h-BN Formation on the Surface of Weld Dissimilar Joint Steels

In-situ observation of h-BN formation by surface precipitation on the surface of joined dissimilar steels is presented. Because the substrate consists of two different types of steels, different growth behaviors can be seen on different sides and also in the middle of the weld interface. This observation demonstrates that formations of 2D materials can occur on surfaces of steels under suitable conditions e.g. temperature, microstructures and concentrations of impurities. Characterizations by electron microscopy and synchrotron spectroscopy technics confirm that h-BN crystals that appear on the surface after annealing are of similar quality to those prepared by other methods such as chemical vapor deposition. Moreover, real-time observation during sample temperature swing above and below the phase transition temperature of Fe shows that h-BN islands reversibly form and dissociate on the surface. The results show that the formation of h-BN on steels is reversible and the analysis suggests that the process is likely affected by structural change of the steels near the phase transition temperature, which in-turn drives the diffusions of B and N atoms back and forth between surface and bulk