Isotherm, kinetic, and thermodynamic study of ciprofloxacin sorption on sediments.
In this study, equilibrium isotherms, kinetics and thermodynamics of ciprofloxacin on seven sediments in a batch sorption process were examined. The effects of contact time, initial ciprofloxacin concentration, temperature and ionic strength on the sorption process were studied. The Kdparameter from linear sorption model was determined by linear regression analysis, while the Freundlich and Dubinin-Radushkevich (D-R) sorption models were applied to describe the equilibrium isotherms by linear and nonlinear methods. The estimated Kdvalues varied from 171 to 37,347 mL/g. The obtained values of E (free energy estimated from D-R isotherm model) were between 3.51 and 8.64 kJ/mol, which indicated a physical nature of ciprofloxacin sorption on studied sediments. According to obtained n values as measure of intensity of sorption estimate from Freundlich isotherm model (from 0.69 to 1.442), ciprofloxacin sorption on sediments can be categorized from poor to moderately difficult sorption characteristics. Kinetics data were best fitted by the pseudo-second-order model (R2> 0.999). Thermodynamic parameters including the Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were calculated to estimate the nature of ciprofloxacin sorption. Results suggested that sorption on sediments was a spontaneous exothermic process.
Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000, Zagreb, Croatia. dmutavdz@fkit.hr.
Dragana
D
Mutavdžić Pavlović
Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 1, 10000, Zagreb, Croatia.
Lidija
L
Ćurković
Department of Polymer Engineering and Organic Chemical Technology, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000, Zagreb, Croatia.
Ivana
I
Grčić
Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000, Zagreb, Croatia.
Iva
I
Šimić
Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 1, 10000, Zagreb, Croatia.
Josip
J
Župan
D000327:Adsorption; D002939:Ciprofloxacin; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013696:Temperature; D013816:Thermodynamics
D002939:Ciprofloxacin
Ciprofloxacin; Ionic strength; Isotherm; Kinetic and thermodynamic study; Sediment; Sorption; Temperature