title: Removal of catechol from aqueous solutions by adsorption onto organophilic-bentonite.
abstract: Organophilic-bentonite, produced by exchange of cetyltrimethylammonium cation for metal cations on the bentonite, was exploited as adsorbent for removal of catechol from aqueous solutions using batch technique. The dependence of removal on various physico-chemical parameters, such as contact time (1-250 min), concentration (0.8-15.3 mmol L(-1)), temperature (30, 40, 50+/-1 degrees C) and pH (5-12) of the adsorptive solution were investigated. Obtained results show that catechol could be removed efficiently ( approximately 100%) at pH values > or =9.9. The uptake process follows first-order rate kinetics and the equilibrium data fit well into the Langmuir and Freundlich adsorption isotherms over a wide range of concentration (1-10 mmol L(-1)). The magnitude of change of free energy (DeltaG degrees ), enthalpy (DeltaH degrees ) and entropy (DeltaS degrees ) were determined.
authors.affiliation: Nuclear Chemistry Department, Hot Laboratories Center, Atomic Energy Authority Post 13759, Cairo, Egypt. kshakir@lycos.com
authors.forename: K
authors.initials: K
authors.lastname: Shakir
authors.forename: H F
authors.initials: HF
authors.lastname: Ghoneimy
authors.forename: A F
authors.initials: AF
authors.lastname: Elkafrawy
authors.forename: Sh G
authors.initials: ShG
authors.lastname: Beheir
authors.forename: M
authors.initials: M
authors.lastname: Refaat
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D002396:Catechols / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012996:Solutions; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D002396:Catechols; D002593:Cetrimonium Compounds; D012996:Solutions; D014874:Water Pollutants, Chemical; D001546:Bentonite; C034221:catechol; D000077286:Cetrimonium