The Impact of Thermal History on Water Adsorption in a Synthetic Nanolayered Silicate with Intercalated Li+ or Na+
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The Impact of Thermal History on Water Adsorption in a Synthetic Nanolayered Silicate with Intercalated Li+ or Na+. / Michels, L.; da Fonseca, C. L. S.; Meheust, Y.; Altoe, M. A. S.; dos Santos, E. C.; Grassi, G.; Droppa, R.; Knudsen, K. D.; Cavalcanti, L. P.; Hunvik, K. W. B.; Fossum, J. O.; da Silva, G. J.; Bordallo, H. N.
In: Journal of Physical Chemistry C, Vol. 124, No. 45, 12.11.2020, p. 24690-24703.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The Impact of Thermal History on Water Adsorption in a Synthetic Nanolayered Silicate with Intercalated Li+ or Na+
AU - Michels, L.
AU - da Fonseca, C. L. S.
AU - Meheust, Y.
AU - Altoe, M. A. S.
AU - dos Santos, E. C.
AU - Grassi, G.
AU - Droppa, R.
AU - Knudsen, K. D.
AU - Cavalcanti, L. P.
AU - Hunvik, K. W. B.
AU - Fossum, J. O.
AU - da Silva, G. J.
AU - Bordallo, H. N.
PY - 2020/11/12
Y1 - 2020/11/12
N2 - For applications benefitting from the swelling properties of nanolayered silicates (clay minerals), it is of paramount importance to understand the hysteresis in the clay-water interaction. In this context, the present work investigates how the thermal history of Na+- and Li+-intercalated fluorohectorite affects the hydration process. By combining X-ray diffraction and thermogravimetric analysis, water adsorption of preheated and non-preheated fluorohectorite was measured and analyzed in terms of the characteristic interlayer distance. The number of water molecules per cation was also inferred. We find that some of the hydration states in preheated samples are suppressed, and transitions to higher hydration states are achieved at higher relative humidity values. This could be due to the initial water content that facilities crystalline swelling. However, the data for Li-fluorohectorite do not exclude the possibility of a low temperature Hofmann-Klemen effect at 150 degrees C. Our study also provides strong hints that the so-called 1.5 water layer state, observed in previous studies on smectites, is a metastable state. In addition, the impact of a hydrogenous structure in the interlayer space of Li-fluorohectorite on the clay's hydration behavior is demonstrated. The results, if generalized, would have strong implications on a wide range of applications, where the thermal history of smectites is important.
AB - For applications benefitting from the swelling properties of nanolayered silicates (clay minerals), it is of paramount importance to understand the hysteresis in the clay-water interaction. In this context, the present work investigates how the thermal history of Na+- and Li+-intercalated fluorohectorite affects the hydration process. By combining X-ray diffraction and thermogravimetric analysis, water adsorption of preheated and non-preheated fluorohectorite was measured and analyzed in terms of the characteristic interlayer distance. The number of water molecules per cation was also inferred. We find that some of the hydration states in preheated samples are suppressed, and transitions to higher hydration states are achieved at higher relative humidity values. This could be due to the initial water content that facilities crystalline swelling. However, the data for Li-fluorohectorite do not exclude the possibility of a low temperature Hofmann-Klemen effect at 150 degrees C. Our study also provides strong hints that the so-called 1.5 water layer state, observed in previous studies on smectites, is a metastable state. In addition, the impact of a hydrogenous structure in the interlayer space of Li-fluorohectorite on the clay's hydration behavior is demonstrated. The results, if generalized, would have strong implications on a wide range of applications, where the thermal history of smectites is important.
KW - MOLECULAR-DYNAMICS SIMULATION
KW - LAYER CHARGE
KW - MONTE-CARLO
KW - CLAY
KW - SMECTITE
KW - HYDRATION
KW - CATION
KW - MONTMORILLONITE
KW - CIPROFLOXACIN
KW - RELEASE
U2 - 10.1021/acs.jpcc.0c05847
DO - 10.1021/acs.jpcc.0c05847
M3 - Journal article
VL - 124
SP - 24690
EP - 24703
JO - The Journal of Physical Chemistry Part C
JF - The Journal of Physical Chemistry Part C
SN - 1932-7447
IS - 45
ER -
ID: 255043855