title: A comparative study of linear and non-linear regression analysis for ammonium exchange by clinoptilolite zeolite.
abstract: Ammonium ion exchange from aqueous solution using clinoptilolite zeolite was investigated at laboratory scale. Batch experimental studies were conducted to evaluate the effect of various parameters such as pH, zeolite dosage, contact time, initial ammonium concentration and temperature. Freundlich and Langmuir isotherm models and pseudo-second-order model were fitted to experimental data. Linear and non-linear regression methods were compared to determine the best fitting of isotherm and kinetic model to experimental data. The rate limiting mechanism of ammonium uptake by zeolite was determined as chemical exchange. Non-linear regression has better performance for analyzing experimental data and Freundlich model was better than Langmuir to represent equilibrium data.
authors.affiliation: Yildiz Technical University, Department of Environmental Engineering, 34669 Besiktas, Istanbul, Turkey. dkaradag@yildiz.edu.tr
authors.forename: Dogan
authors.initials: D
authors.lastname: Karadag
authors.forename: Yunus
authors.initials: Y
authors.lastname: Koc
authors.forename: Mustafa
authors.initials: M
authors.lastname: Turan
authors.forename: Mustafa
authors.initials: M
authors.lastname: Ozturk
mesh_terms: D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012044:Regression Analysis; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D017641:Zeolites / Q000737:chemistry*
chemical_list: D000644:Quaternary Ammonium Compounds; D014874:Water Pollutants, Chemical; C083175:clinoptilolite; D017641:Zeolites