title: Removal of C.I. Reactive Red 2 from aqueous solutions by chitin: an insight into kinetics, equilibrium, and thermodynamics.
abstract: In this study, C.I. Reactive Red 2 (RR2) was removed from aqueous solutions by chitin. Exactly how the RR2 concentration, chitin dosage, pH, and temperature affected adsorption of RR2 by chitin was then determined. After reaction for 120 min, the amount of 10 and 20 mg/L RR2 absorbed onto chitin was 5.7 and 7.5 mg/g, respectively. The adsorption percentage increased from 56 to 94% when the chitin dosage was increased from 1.5 to 2.5 g/L. Experimental results indicated that the pseudo-second-order model best represents adsorption kinetics. Adsorption of RR2 increased as the temperature increased; however, it decreased with an increased pH. Experimental results further demonstrated that the Freundlich model is superior to the Langmuir model in fitting experimental isotherms. The ΔH° and ΔS° were 16.34 kJ/mol and 152.10 J/mol K, respectively. ΔH° suggested that adsorption of RR2 onto chitin was via physisorption.
authors.affiliation: Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chien Kung Road, Kaohsiung 807, Taiwan. wuch@kuas.edu.tw
authors.forename: C H
authors.initials: CH
authors.lastname: Wu
authors.forename: C Y
authors.initials: CY
authors.lastname: Kuo
authors.forename: C H
authors.initials: CH
authors.lastname: Yeh
authors.forename: M J
authors.initials: MJ
authors.lastname: Chen
mesh_terms: D002686:Chitin / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D007700:Kinetics; D009282:Naphthalenesulfonates / Q000737:chemistry*; D013816:Thermodynamics; D014227:Triazines / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical
chemical_list: D004396:Coloring Agents; D009282:Naphthalenesulfonates; D014227:Triazines; D014874:Water Pollutants, Chemical; C098610:reactive red 2; D014867:Water; D002686:Chitin