Sequential modification of cationic and anionic nanoclays with ionic liquids

exchange of a cationic nanoclay from a solution containing phosphonium cations that remained after an anionic nanoclay exchange reaction with an ionic liquid (IL) was successful in increasing the cationic nanoclay basal spacing for nanocomposite applications requiring improved filler dispersion. This modification method minimizes through their reuse, the formation of waste, toxic solutions that are to be discarded. The results are compared with data from the direct modification of the cationic clay with a solution of the same IL. To verify the intercalation of residual cations, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, and X-ray diffraction were used. All these results show that the residual cation after anion exchange modification successfully intercalated into the clay gallery to the same degree as the original IL. The sequential clay modification approach in this communication conforms to established green chemistry principles from the viewpoints of waste prevention (recycle, reuse) and minimization of toxic chemicals in the environment.