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Adsorption of sodium dodecyl sulphate on cassiterite surface
Author(s) -
GonzálezMartín M. L.,
Janczuk B.,
Bruque J. M.,
DoradoCalasanz C.
Publication year - 1994
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450720323
Subject(s) - adsorption , cassiterite , chemistry , sodium dodecyl sulfate , monolayer , ion , critical micelle concentration , inorganic chemistry , micelle , sodium , inflection point , molecule , chromatography , aqueous solution , organic chemistry , biochemistry , tin , geometry , mathematics
Measurements of the adsorption of sodium dodecyl sulphate (SDS) onto cassiterite were made. It was found that at SDS concentrations below 10 −3 mol/L the adsorption depended on the manner of preparation of the cassiterite and the pH of solution. However, the adsorption isotherms showed a point of inflection at l0 −3 mol/L corresponding to an occupied area per molecule of about 0.8 nm 2 . This value is close to the surface area covered by one dodecyl sulphate ion (DS − ) as evaluated from the molecular structure of SDS. Near the critical micelle concentration (cmc), a plateau was found which corresponded to the adsorption of two statistical monolayers of DS − ions vertically oriented to the surface.