Surface thermodynamic properties of micas and related layer silicate minerals
Surface thermodynamic properties of micas and related layer silicate minerals
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DOI:
10.1080/01932699808913214
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发表时间:
1998-01-01
影响因子:
2.2
通讯作者:
van Oss, CJ
中科院分区:
文献类型:
--
作者:
Giese, RF;Wu, W;van Oss, CJ
The surface tension values for a series of 2:1 phyllosilicate minerals with different structural characteristics and layer charges ranging from 0 to 2 per O-10 group have been examined. The average Lifshitz-van der Waals component (gamma(LW))value is 40.3 +/- 1.9 mJ/m(2), and the average Lewis acid (gamma(+)) parameter is 1.2 +/- 0.6 mJ/m(2) for those minerals with a layer charge greater than zero. In contrast, the Lewis base parameter (gamma(-)) varied greatly from a maximum of 59.7 mJ/m(2) to a minimum of 23.7 mJ/m(2). Those minerals with a layer charge of zero (three samples) had smaller gamma(LW) values of 32.0 +/- 1.6 mJ/m(2), slightly larger gamma(+) values of 2.0 +/- 0.4 mJ/m(2) and significantly smaller values of gamma(-) of 4.5 +/- 1.6 mJ/m(2). The hydrophobic versus hydrophilic character of these materials is largely governed by the value of gamma(-) which is strongly related to the value of the layer charge.Thus, the hydrophilicity of a smectite is determined by the charge unbalancing ionic substitutions which attract hydrophilic interlayer cations and render adjacent oxygen atoms of the particle surface hydrophilic.