Functionalization of montmorillonite with ionic liquids based on 1-alkyl-3-methylimidazolium: Effect of anion and length chain

In this work a series of ionic liquids based on 1-alkyl-3-methylimidazolium cations with Br−, OH− and BF4− anions were synthesized and characterized by FT-IR, 1HRMN and TGA. The alkylic chain length was modified by using butyl, octyl and hexadecyl substituents. These ionic liquids were used as functionalizing agents of sodium montmorillonite and the final material were characterized by means of XRD, FT-IR and TGA. The results show a significant increase in the interlayer space for the montmorillonite as the length carbon chain increases. In all cases it was possible an ionic liquid incorporation on montmorillonite more than 10% w/w. The presence of BF4− anion promotes thermal stability of the material whereas OH− ion increases the ionic liquid amount that can be incorporated into the clay due to its favorable interactions with the phyllosilicate structure. The final organo-clay minerals are promising materials for removing organic composes from water.