Interfacial electrochemical properties of a Moroccan bentonite in aqueous suspension

In this work,the interfacial electrochemical properties of a purified moroccan bentonite have been studied. the conductometric studies showed that the bentonite particles were stable in aqueous phase in the studied ph range (3-12). the potentiometric titration results obtained in the presence of various concentrations of non-specifically adsorbed electrolytes showed that the point of zero charge shifted to lower ph values by increasing electrolyte concentrations. this behavior was attributed to the combined effect of both variable charges and structural negative charges. the adsorption sequence's study carried out at various ionic strengths showed that the bentonite particles in aqueous phase behave as a water structure organizer at ph below to phpzc,while at ph range superior to phpzc they behave as a water structure disorganizer. the total number of surface sites,determined by using the graphical extrapolation method,was 7.4 oh/nm2. based on the obtained values of the complexation constants,it was concluded that the adsorption of non-specifically ions (li+,na+,cl- and br-) was exclusively electrostatic whereas that of specifically ions (cs+ and f-) was both electrostatic and specific nature. © 2017,university of mohammed premier oujda morocco.