Adsorption of methane with the presence of water on oxide, polymer and carbon adsorbents studied using 1H NMR spectroscopy at low temperatures

Co-adsorption of water and methane onto polymeric adsorbent LiChrolut EN, activated carbon adsorbent, fumed alumina and Silochrome modified by 3-aminopropylmethyldimethoxy silane was studied using 1H NMR spectroscopy with layer-by-layer freezing out of bulk and bound adsorbates. At a certain amount of adsorbed water the adsorption of methane can increase. Bound water can be in strongly (changes in Gibbs free energy ΔG < −1 kJ/mol) and weakly (ΔG > −1 kJ/mol) bound and strongly (chemical shift of the proton resonance δH = 3–6 ppm) and weakly (δH = 1–2 ppm) associated states. With the presence of adsorbed methane contribution of weakly associated water increases.