DFT method nanosilica нанокремнезем DFT метод Surface chemistry of silica and related sorbents ab initio and DFT methods activated carbon models adsorption models alumina/silica/titania atom charge distribution function binary nanooxides bound aqueous solutions bound water organization carbon adsorbents charged sorbates confined space effect cryoscopic effect electronic structure fumed silica high-pressure cryogelation hydrophobized nanosilica interfacial phenomena kefir grains low-temperature 1H NMR spectroscopy methane adsorption mixed phases morphological and textural characteristics nanoalumina neutral sorbates organic solvent adsorption