The characterisation and use of polycation-exchanged bentonites

The interaction of polymers with clays is considered with particular emphasis on the adsorption of polycations of the type [CH2CHOHCH2N(CH3)(2)](n)(n+) onto a low iron Texas bentonite, Westone-L (WL). The influence of clay type, particle size and resident cation on the amount of adsorbed polycation is reported along with variable temperature X-ray diffraction of the resulting complexes. The information obtained from Cs+- and Na+-WL suspensions using Cs-133 and Na-23 solution phase NMR is summarised and used to show that this technique can provide quantitative information regarding the displacement of Cs+-ions from the exchange sites by polycation in suspension and reflect subtle in situ changes intimated from Zeta potential measurements. The use of polycation-exchanged clays as scavengers of p-nitrophenol from water is described as is the significant activity of acid-treated polycation-exchanged clays for the catalytic isomersion of alpha-pinene to camphene and limonene. (C) 1999 Published by Elsevier Science B.V. All rights reserved