¹H NMR Investigations of Activated Carbon Loaded with Volatile Organic Compounds: Quantification, Mechanisms, and Diffusivity Determination

Abstract

Three volatile organic compounds (benzene, cyclohexane, dichloromethane) were adsorbed onto activated carbon fiber cloth.1 H (MAS and PFG) NMR techniques were carried out and the signals were analyzed in terms of peak surface areas and shifts. These techniques were shown to be very useful for determining i) the intrinsic quantification of adsorbed molecules (VOC and/or water) in the porosity of the materials; the adsorption capacities ranged from 0.2 to 4 mol.kg -1 , ii) the mechanisms of interactions between adsorbed organic molecules and the carbon walls;

Structures and Dynamics of Secondary and Tertiary Alkylphosphine Oxides Adsorbed on Silica

“…The impurity signal at 68.11 ppm (Figure ) most likely stems from THF, a ubiquitous solvent and volatile organic compound (VOC) that the silica support adsorbed while the sample was packed in a glovebox.…”

NMR relaxation and modelling study of the dynamics of SF6 and Xe in porous organic cages

“…1,2 They also provide promising opportunities to capture greenhouse gases by adsorption, 3 such as CO 2 , CH 4 , as well as noble gases 4,5 (Xe, Ar, Kr). Various extended porous networks have been developed for these applications, such as activated carbons, 6 zeolites, 7 metal organic frameworks (MOFs), 8 covalent organic frameworks (COFs) 9 and porous polymers. 10 Nuclear magnetic resonance (NMR) relaxation and diffusion experiments provide extraordinarily versatile information about dynamics of fluid molecules in porous media.…”

“…18 Several extended porous solids 19,20 have been utilised for the separation and adsorption of SF 6 . Moreover, cucurbituril in aqueous solution 21 has also been utilised for the reversible trapping of SF 6 .…”

“…Adsorbed xenon (with diameter of 4.3 Å) was shown to have fast exchange, on the order of 10 8 s À1 , between these cavities, 28 and even SF 6 with kinetic diameter of 5.5 Å can enter the cage through the window cavity because of thermal and vibrational motion of the porous organic crystals. 27 The fluorine atoms in SF 6 have an NMR active 19 F isotope with spin-1/2, high gyromagnetic ratio and 100% natural abundance. The presence of six magnetically equivalent 19 F atoms in each SF 6 molecule makes the spin density of the gas high.…”

Preparation of a Composite Material AC/Cu-BTC with Improved Water Stability and n-Hexane Vapor Adsorption

“…AC is one of the earliest and widest applied conventional adsorbents with stable performance and corrosion resistance. The AC is hydrophobic and it has a nonpolar surface with affinity for organic matter [24]. Traditional and new adsorbents have their own advantages and disadvantages and combing them together may produce unexpected results.…”