SYNTHESIS AND CHARACTERIZATION OF AL-PILLARED AND CATIONIC SURFACTANTMODIFIED AL-PILLARED ALGERIAN BENTONITE

Al-pillared and a cationic surfactant modified Al-pillared montmorillo nite were prepared by reacting a purified bentonite from deposits in M aghnia and Mostaghanem (in the West of Algeria), with a solution of al uminum chlorohydrate alone or with both Al-chlorohydrate and cetyl tri methyl ammonium bromide (CTAB) solutions. The most favorable condition s for producing the Al-pillared and the CTAB-modified Al-pillared mont morillonite were established as follows: an OH/Al molar ratio of 1.8; an Al/bentonite ratio of 4 mmol/g; a CTAB/bentonite ratio of 2 (w/w). The Al-pillared clays have a basal spacing of about 1.8 nm and a surfa ce area between 250 and 300 m(2)/g. A good thermal stability was found at 500 degrees C. The CTAB modified Al-montmorillonite showed a great er basal spacing of about 2.1 nm, but it was reduced down to 1.4 nm up on heating to 500 degrees C when the CTAB was adsorbed on the Al-hydro xy-montmorillonite prior the calcination and to 1.8 nm when it was ads orbed on the calcined pillared solid. The BET surface area of CTAB mod ified Al-montmorillonite was much lower than that of Al-pillared clays .