title: The sorption of sulfamethazine on soil samples: isotherms and error analysis.
abstract: In this paper, batch sorption of sulfamethazine on eight soil samples (six from Croatia and two from Bosnia and Hercegovina) with different organic matter contents ranging from 1.52 to 12.8% was investigated. The effects of various parameters such as agitation time, initial concentration, and ionic strength on the sulfamethazine sorption were studied. The experimental data were analysed using a one-parameter model, Linear isotherm, and two two-parameter models, the Freundlich and Dubinin-Radushkevich isotherms. The goodness of fit was measured using the linear regression and the determination coefficient (R(2)) value. Also, the equilibrium data of the two-parameter models were analysed using the residual root mean square error (RMSE), the sum of squares of errors (ERRSQ), and a composite fractional error function (HYBRID). Non-linear regression has better characteristics for analysing experimental data. The obtained sorption coefficients Kd (from 0.25 to 8.10 mL/g) and the Freundlich sorption coefficients KF (from 1.16 to 7.99 (μg/g)(mL/μg)(1/n)) exhibited quite low values, which indicated that sulfamethazine is weakly adsorbed on the evaluated soils, is highly mobile, and has a great potential to penetrate and pollute the ground water. The Dubinin-Radushkevich isotherm was used to estimate the apparent free energy of sorption.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, Croatia. Electronic address: dmutavdz@fkit.hr.
authors.forename: Dragana
authors.initials: D
authors.lastname: Mutavdžić Pavlović
authors.affiliation: Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 1, 10000 Zagreb, Croatia.
authors.forename: Lidija
authors.initials: L
authors.lastname: Ćurković
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, Croatia.
authors.forename: Dijana
authors.initials: D
authors.lastname: Blažek
authors.affiliation: Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 1, 10000 Zagreb, Croatia.
authors.forename: Josip
authors.initials: J
authors.lastname: Župan
mesh_terms: D000327:Adsorption; D007700:Kinetics; D008956:Models, Chemical; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D013418:Sulfamethazine / Q000032:analysis / Q000737:chemistry*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D013418:Sulfamethazine
keywords: Isotherms; Modelling; Soil; Sorption; Sulfamethazine