title: The removal of phenolic compounds from aqueous solutions by organophilic bentonite.
abstract: The adsorption of p-chlorophenol (p-CP) and p-nitrophenol (p-NP) on organophilic bentonite (dodecylammonium bentonite, DDAB) was studied as a function of solution concentration and temperature. The observed adsorption rates were found to be equal to the first-order kinetics. The rate constants were calculated for temperatures ranging between 25.0-35.0 degrees C at constant concentration. The adsorption energies, E and adsorption capacity, (qm), for phenolic compounds adsorbed to organophilic bentonite were estimated by using the Dubinin-Radushkevic equation. Thermodynamic parameters from the adsorption isotherms of p-CP and p-NP on organophilic bentonite were determined. These isotherms were modeled according to Freundlich and Dubinin-Radushkevic adsorption isotherms and followed the V-shaped isotherm category with two steps. The amount of adsorption was found to be dependent on the relative energies of adsorbent-adsorbate, adsorbate-solvent and adsorbate-adsorbate interaction.
authors.affiliation: Department of Chemistry, Faculty of Science a a related to sorption energynd Art, University of Dicle, TR 21280, Diyarbakir, Turkey. makcay@dicle.edu.tr
authors.forename: Mehmet
authors.initials: M
authors.lastname: Akçay
authors.forename: Gülten
authors.initials: G
authors.lastname: Akçay
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D002733:Chlorophenols / Q000302:isolation & purification*; D007700:Kinetics; D009596:Nitrophenols / Q000302:isolation & purification*; D012996:Solutions; D014867:Water / Q000737:chemistry*
chemical_list: D002733:Chlorophenols; D009596:Nitrophenols; D012996:Solutions; D014867:Water; D001546:Bentonite; C029107:4-chlorophenol; C024836:4-nitrophenol