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Investigation of the effects of hydrochloric acidmodification on the structural of Algerian-bentonite clay

Bendou Samira, Amrani Moussa

The objective of this work is to determine changes of surface properties of a bentonite after acid activation, usinghydrochloric acid solutions (HCl) at roomtemperature.XRD, FX, FTIR,MEB, andBET analyses of the samples have been carried out to examine the structure of bentonite before and after acid activation. It is found that the rawbentonite is composed ofdioctahedralmontmorillonitewithpredominantquantity and certain amounts of quartz, orthodase, albiteandillite, etc.. It also has a CEC of 74.32meq/g which allowit to be characterized as typical sodium bentonite. Changes at low acid concentrations have resulted fromcations exchange (exchangeable cations withH+ ions).Differences of surface area at high acid concentrations (0.25 - 0.4M) have been caused by structural changes and partial decomposition of the samples. Surface areameasurements have showed that with the increase of concentration ofHCl solution the surface area has increased. the maximum value (837.11m2/g) has been reached bythe sample activated with 0.4MHCl.Activationwith higher concentration (0.6M) has caused a decrease in the surface area.