title: Adsorption of basic dyes onto montmorillonite.
abstract: Ca-montmorillonite (Ca-Mont) was exchanged with titanium cations and the adsorption equilibrium and kinetics of Basic Green 5 (BG5) and Basic Violet 10 (BV10) on these montmorillonites were measured to examine the ion-exchange effects on the basic dyes adsorption. The relationship between the dye adsorption and the alteration of pore structures of montmorillonite induced by ion-exchange processes was discussed. Moreover, the changes in the surface and pore structure of montmorillonites during adsorption were characterized based on classical and fractal analyses of the nitrogen adsorption isotherms as well as the XRD patterns. The decrease in BET surface area of montmorillonites after adsorption of dyes was interpreted in terms of both the coverage of some surface roughness (surface screening effect) and the inhibition of the movement of nitrogen molecule into some pores (pore blocking effect). The surface fractal dimension D was used to examine whether or not the surface screening effect exists and the pore blocking effect was examined with the changes of mean pore size before and after adsorbing basic dyes.
authors.affiliation: Green Environment R&D Center and Department of Environmental Engineering, Van-Nung Institute of Technology, Chung-Li 320, Taiwan, Republic of China.
authors.forename: Cheng-Cai
authors.initials: CC
authors.lastname: Wang
authors.forename: Lain-Chuen
authors.initials: LC
authors.lastname: Juang
authors.forename: Ting-Chu
authors.initials: TC
authors.lastname: Hsu
authors.forename: Chung-Kung
authors.initials: CK
authors.lastname: Lee
authors.forename: Jiunn-Fwu
authors.initials: JF
authors.lastname: Lee
authors.forename: Fu-Chuang
authors.initials: FC
authors.lastname: Huang