“…The catalytic effects of PAHs in acidic reactions depends on three factors: acidity, heteropolianion structure and the type of reaction. On the other hand, clays may be used as catalyst support [9,13,16,20,25,26,34,41,44], or act as acid catalysts [7,8,38,39], redox catalysts and in removing heavy metals from the environment from modifications [45,46]. Both the modified-bentonite and bentonite are promising supports due to their common fascinating features, such as their inherent acidity, excellent thermal stability, and easily controlled structure and morphology.…”