1 Introduction Bentonite is a valuable industrial material, which is composed mainly of montmorillonite. Due to many particular characteristics such as strong water sorbility, dilatability, stickiness, high ion-exchangeable capacity, Bentonite has been used widely in many fields of application, including petroleum, metallurgy and chemical industry, textile industry, medical application, construction, mining, agriculture, environment (Koch, 2002; Wang and Wu, 2002; Wagner and Schnatmeyer, 20…