“…Due to isomorphous substitution effect, Mt layers contain negative charges, which are counterbalanced by inorganic cations (e.g., Na + , Ca 2+ ) (Brigatti et al, 2006). These inorganic cations are exchangeable, making Mt efficient adsorbent for various cationic contaminants, such as heavy metals (Bailey et al, 1999;Bhattacharyya and Gupta, 2008;Krishna and Susmita, 2006), cationic dyes (Eren and Afsin, 2008;Gupta and Suhas, 2009;Rytwo and Ruiz-Hitzky, 2003), and cationic surfactants (Li and Rosen, 2000;Li et al, 2006;Ma and Zhu, 2007). After the adsorption of organic cations, interlayer space of Mt can change from hydrophilic to hydrophobic, and the resulting materials, also known as organoclays, have been used as efficient adsorbents for hydrophobic organic contaminants (HOC) (Chen et al, 2005;Ramesh et al, 2007;Rytwo and Gonen, 2006;Shen, 2002Shen, , 2004Zhu et al, 2007).…”