Structures and Wettability Alterations of a Series of Bispyridinium Dibromides Exchanged with Reduced-Charge Montmorillonites

Capillary rise tests were performed to investigate the influences that the structure of the modifier and layer charge of clay had on wetting properties of organoclays, which were prepared by ion exchange using bispyridinium dibromides (BPs) with different spacer length and the reduced-charge montmorillonites (RCMs). Their structures were examined by Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), and nitrogen adsorption–desorption isotherms. The results indicated that BPs had been successfully intercalated into interlayers and lay in the monolayer. The d001 basal spacing of organo-RCMs increased with the spacer length of BPs increasing, whereas it decreased gradually as the layer charge of the RCMs was decreased, independent of the type of BPs. Whether the organic modification made the Brunauer–Emmett–Teller (BET) surface area increase or decrease depended upon the size of the organic cations and the layer charge of the clays. The wettability alterations of the organo-RCMs for d...