Adsorption of carbon dioxide on montmorillonites of different ion exchange forms

Interlayer Cation-Controlled Adsorption of Carbon Dioxide in Anhydrous Montmorillonite Clay

“…A rather large |Δ H | on materials with more narrow micropores is also observed in simulations and on activated carbon , and can be attributed to the increased interactions of the adsorbing molecules due to the close presence of two surfaces at the same time (instead of one). The value found for the sorption enthalpy Δ H for TMA-MMT, where the interlayer spacing is large and hence simultaneous interactions with two surfaces are suppressed, is also in good agreement with the sorption enthalpy on the external surface of similar MMTs (20–21 kJ mol –1 ) …”

“…The value found for the sorption enthalpy ΔH for TMA-MMT, where the interlayer spacing is large and hence simultaneous interactions with two surfaces are suppressed, is also in good agreement with the sorption enthalpy on the external surface of similar MMTs (20−21 kJ mol −1 ). 31 The accessibility of the interlayer, b 0 , increases with increasing radius of the interlayer cation and varies almost 2 orders of magnitude between NH 4 -MMT and Cs-MMT and between Cs-MMT and TMA-MMT. Even small variations in the ionic radius (in particular NH 4 + to Cs + ) thus strongly affect the sorption characteristics of the respective MMTs.…”

“…Montmorillonite (MMT), a member of the layered aluminosilicate smectite clay mineral group, has attracted substantial attention for sorption purposes due to its natural abundance, thermal and mechanical stability, and large (interlayer) specific surface areas of up to ∼800 m 2 g –1 . In the absence of solvents sorbed in the interlayer space, its interlayer spacing isto a large extentset by exchangeable cations in the interlayer space compensating for negative charges in each MMT layer. , Due to the large interlayer surface area of MMT and smectites in general, their interlayer adsorption capacity for solvents (in particular water, − and also for CO 2 − and/or methane − ) can be significantly larger than their sorption capacity on the external surfaces only, provided that the interlayer space is accessible for the species to be sorbed.…”

In situ XRD study of Ca2+ saturated montmorillonite (STX-1) exposed to anhydrous and wet supercritical carbon dioxide

“…In contrast, other experimental work at low temperatures (Aylmore, 1977) indicated that CO 2 adsorbed to external surfaces and did not become intercalated within the montmorillonite structure, although the degree of adsorption was similarly influenced by the hydration energies of exchangeable cations. More recently and at higher temperatures (30-123 • C) and pressures (1-60 bar) Pribylov et al (2010) exposed Na + saturated montmorillonite to subcritical CO 2 and concluded that CO 2 adsorbed on external surfaces of the clay but not within the interlayers, although the initial hydration state of the clay was not given.…”

Experimental methods to study clay minerals and perspective applications of Fluorohectorite

“…Table 2, it is observed that the CO2 uptake by clays ranges from 0.2 mmol/g to 6.4 mmol/g. As illite (I) is harder to swell, its uptake is lower and varies from 0.2 mmol/g [79] to 0.4 mmol/g [80] , while Kaol [81] and Bent [82] have similar uptake. Mt is the most studied clay species and present the maximum CO2 uptake of 2 mmol/g [83] for the pure material [84,85,86,87] , and higher values for functionalized structures [80,88] , like 3.2 mmol/g for the polymer modified PEI-Mt [89] or 3.8 mmol/g for the nano-Mt [90] .…”