Reduced-charge montmorillonite (RCM, cation exchange capacity (CEC)=7.5 cmol c kg −1 ) prepared by heating Li + -montmorillonite (CEC=98.1 cmol c kg −1 ) at 400°C for 2 h could be finely dispersed in a mixture of water, dimethylformamide, and ammonia, as confirmed by particle size distribution and atomic force microscopy measurements. Upon dispersion, the CEC of RCM increased to 51.8 cmol c kg −1 , and about 50% of fixed Li + ions was converted into exchangeable ones.