title: Mechanism of sorption of phenols from aqueous solutions onto surfactant-modified montmorillonite.
abstract: Equilibrium and kinetic studies on the sorption of phenol, m-nitrophenol (m-NP), and o-cresol from water onto montmorillonite modified with cetyltrimethylammounium bromide (CTAB) were conducted. Experiments were carried out as a function of solution pH, sorbate concentration, and temperature (25-55 degrees C). It was shown that the sorption capacity decreased in the order phenol>o-cresol>m-NP. The Langmuir, dual-mode sorption, and Redlich-Peterson models were tested to fit the sorption isotherms of single-solute systems, whereas the Langmuir competitive model was used to describe bisolute sorption equilibria. Thermodynamic parameters (DeltaH degrees and DeltaS degrees ) and the mean free energy (E) for the sorption of phenols were determined from the temperature dependence of the distribution constant and the Dubinin-Radushkevick equation, respectively. A simplified kinetic model was proposed to confirm the sorption mechanism.
authors.affiliation: Department of Chemical Engineering, Yuan Ze University, Chung-Li, 320, Taiwan. cejuang@ce.yzu.edu.tw
authors.forename: Ruey Shin
authors.initials: RS
authors.lastname: Juang
authors.forename: Su Hsia
authors.initials: SH
authors.lastname: Lin
authors.forename: Kung Hsuen
authors.initials: KH
authors.lastname: Tsao