Daiki Minami

Dynamic Quantum Molecular Sieving Separation of D2 from H2–D2 Mixture with Nanoporous Materials

Quantum molecular sieving separability of D(2) from an H(2)-D(2) mixture was measured at 77 K for activated carbon fiber, carbon molecular sieve, zeolite and single wall carbon nanotube using a flow method. The amount of adsorbed D(2) was evidently larger than H(2) for all samples. The maximum adsorption ratio difference between D(2) and H(2) was 40% for zeolite (MS13X), yielding a selectivity for D(2) with respect to H(2) of 3.05.

Aqueous nanosilica dispersants for carbon nanotube.

Nanosilicas can disperse single-wall carbon nanotube (SWCNT) in aqueous solution efficiently; SWCNTs are stably dispersed in aqueous media for more than 6 months. The SWCNT dispersing solution with nanosilica can produce highly conductive transparent films which satisfy the requirements for application to touch panels. Even multiwall carbon nanotube can be dispersed easily in aqueous solution. The highly stable dispersion of SWCNTs in the presence of nanosilica is associated with charge transfer interaction which generates effective charges on the SWCNT particles, giving rise to electrostatic repulsion between the SWCNTs in the aqueous solution. Adhesion of charged nanosilicas on SWCNTs in the aqueous solution and a marked depression of the S11 peak of optical absorption spectrum of the SWCNT with nanosilicas suggest charge transfer interaction of nanosilicas with SWCNT. Thus-formed isolated SWCNTs are fixed on the flexible three-dimensional silica jelly structure in the aqueous solution, leading to the uniform and stable dispersion of SWCNTs.

Enhanced CO 2 adsorptivity of SWCNT by polycyclic aromatic hydrocarbon intercalation

We tuned the electronic properties of single wall carbon nanotube (SWCNT) with intercalation of naphthalene derivatives (NDs) having different electron donor or acceptor property in the SWCNT bundles. Characterization of the adsorbed SWCNT with Raman spectroscopy and electrical conductivity measurement clearly indicate the charge transfer interaction of ND molecules with SWCNT. Also X-ray diffraction supports the intercalation of ND molecules in the interstitial spaces and groove sites of SWCNT bundle. Intercalation of ND molecules enhances remarkably the CO2 adsorptivity, which can be ascribed to the key importance of the interaction of the quadrupole moment of CO2 with the local electrical field on the SWCNT induced by the charge transfer interaction.

Noticeable Reverse Shift in the Melting Temperatures of Benzene and Carbon Tetrachloride Confined within the Micropores and Mesopores of Hydrophobic Carbons

Carbon aerogels contain both mesopores and micropores. In this study, benzene/CCl4 was adsorbed in the pores of carbon aerogels (both mesopores and micropores) and their phase behaviours were examined using differential scanning calorimetry. The bulk solid benzene melted at 278 K and the melting temperatures of benzene confined inside the mesopores and micropores of carbon aerogels were 258 and 293 K, respectively. Although the melting temperature depression of condensates in mesopores is well known, the observed elevation of the melting temperature for micropores is very limited in the strongly interacted system. Similar melting behaviours were observed for the confined CCl4; depression by 45 K in mesopores and elevation by 48 K in micropores showed about two times the change as compared with that of confined benzene.