Physico-Chemical Characterizations of Tunisian Organophilic Bentonites

International audienceOrganoclays were prepared from two tunisian purified Na-bentonites using benzyltetradecyldimethylammonium chloride (C14) and benzyldodecyldimethylammonium chloride (C12). The added quantities of organic salts, expressed as a function of the clay's cationic exchange capacity (CEC), have been varied from 0.3 to 4 CEC. Two different methods were investigated in order to determine the influence of the preparation method on the adsorption properties: on one hand, dry powder clay (method I) and, on the other hand, aqueous clay suspensions (method II) were mixed with the organic salt solutions. The adsorption of organic cations on clays was studied by adsorption isotherms, FTIR spectroscopy and X-ray diffraction. It appears that more salts are adsorbed in the clay interlayer space when using method II. The arrangement of salts within clay is rather complicated. It depends on clay composition, nature of tensioactive molecules, CEC of the clay, and preparation method. According to these parameters, the inserted surfactants can be arranged in monolayer, paraffin, or admicelles structures