title: Use of beta-cyclodextrin and starch based polymers for sorption of Congo red from aqueous solutions.
abstract: Two starch-based and a beta-cyclodextrin (beta-CD)-based polymers were synthesized using 4,4'-methylene-bis-phenyldiisocyanate (MDI) or hexamethylenediisocyanate (HMDI) as a cross linking agent in dry dimethylformamide and used as a sorbent for the removal of Congo red from aqueous solutions. The cross-linked polymers were characterized by Fourier transform infrared spectroscopy, thermogravimetric and differential scanning calorimetric analysis. The dye adsorption experiments were carried out by using batch and recycling column procedure. The effects of initial pH (pH(0)), the contact time and the initial dye concentration were changed to obtain the best experimental conditions. The pH(0) of the dye solution strongly affected the chemistry of both the dye molecules and polymer 3 in an aqueous solution. The effective pH(0) was 7.0 for adsorption on polymer 3. The equilibrium adsorption data were interpreted using Langmuir and Freundlich models. The adsorption of Congo red was better represented by the Freundlich equation.
authors.affiliation: Selçuk University, Department of Chemistry, 42031 Konya, Turkey. myilmaz@selcuk.edu.tr
authors.forename: Elif Yilmaz
authors.initials: EY
authors.lastname: Ozmen
authors.forename: Mustafa
authors.initials: M
authors.lastname: Yilmaz
mesh_terms: D000327:Adsorption; D002623:Chemistry Techniques, Analytical / Q000379:methods; D003224:Congo Red / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000138:chemical synthesis*; D013213:Starch / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D011108:Polymers; D014874:Water Pollutants, Chemical; D047392:beta-Cyclodextrins; D003224:Congo Red; D013213:Starch