Unusual properties of water at hydrophilic/hydrophobic interfaces

Impact of mineral micropores on transport and fate of organic contaminants: A review

“…An approach based on measuring the gas phase sorption and desorption of a VOC on microporous minerals under dry (without water vapor) and wet (in the presence of saturated water vapor) conditions has been recently proposed to quantify the hydrophobic properties of their micropores Reinhard, 2006a, 2010). Spectroscopic techniques, such as nuclear magnetic resonance (NMR) and infrared spectroscopy (IR), can probe the behaviors of water and organic molecules shielded in mineral micropores (e.g., Farmer, 1993, 1995;Aochi et al, 1992Aochi et al, , 2003Chang et al, 2003;Gun'ko et al, 2005;Kustanovich and Goldfarb, 1991;Vittadini et al, 2003). Improvement and refinement in these techniques are necessary to gain more insights on the physical and chemical behaviors of molecules sorbed in mineral micropores.…”

High-pressure cryogelation of nanosilica and surface properties of cryosilicas

“…This technique has been applied to a variety of adsorbates and solid and polymeric adsorbents, biomaterials, cryogels, etc. ; and methods have been described in detail elsewhere [5,16,17].…”

“…The function f(C H2O ) was determined by measurements of the total integral intensity of the 1 H NMR spectra after known amounts of water were added to the materials at T > 273 K. The low-temperature 1 H NMR spectroscopy provides structural information on interfacial water, pore structure (with cryoporometry and relaxometry), and thermodynamic characteristics of bound water or other liquids [16,17]. These characteristics include changes in Gibbs free energy caused by the adsorption (G) of strongly bound water (SBW), G s < 0.5 kJ/mol, and weakly bound water (WBW), G w > 0.5 kJ/mol.…”

“…Repeated measurements of samples gave identical spectra, within experimental error, at the same temperature. To prevent supercooling, spectra were recorded at T = 200 K (for samples precooled to this temperature for 10 min), then heated to 290 K at a rate of 5 K/min with steps T = 10 K or 5 K (with a heating rate of 5 K/min for 2 min), and maintained at a fixed temperature for 8 min [16,17] for data acquisition at each temperature.…”

“…where Т = 273.16 T at T  273.15 K. Equation (1) was used to estimate the G(T) function for bound water [16]. The area under the G(C uw ) curve (the temperature dependence of G(T) and amounts of unfrozen pore water C uw (T) can be transformed into the relationship G(C uw )) which determines overall changes in the Gibbs free energy of interfacial water as shown in Eq.…”