Novel polymer/surfactant modified montmorillonite hybrids and the implications for the treatment of hydrophobic organic compounds in wastewaters

Polydiallyldimethylammonium (PDADMA) and cationic surfactant cetyltrimethylammonium (CTMA) were applied simultaneously to modify montmorillonite, with the aim to synthesize novel organo montmorillonites with a high sorption capacity towards organic pollutants. The basal spacings of the resulting organo montmorillonites (C/P-Mt) were characterized with XRD, and their sorption characteristics for phenol were investigated. It showed that C/P-Mt had larger basal spacings than the corresponding CTMA modified montmorillonite (C-Mt), which indicated that both CTMA and PDADMA were intercalated into the interlayer spaces of the montmorillonite. C/P-Mt was shown to have much better sorption capacity towards phenol than the corresponding C-Mt, and the maximum increase of sorption coefficient (i.e., Kd) and the organic carbon normalized sorption coefficient (i.e., Koc) reached 45% and 20%, respectively. The possible reason for the enhanced sorption capacity is that the intercalation of PDADMA caused a change in the arrangement of the CTMA micelles, which might then lead to the increased affinity towards phenol. Results of this work showed that simultaneous intercalation of cationic polymers could be a possible method for increasing the sorption capacity of the traditional surfactant synthesized organo montmorillonites.