title: Sodium, ammonium, calcium, and magnesium forms of zeolite Y for the adsorption of glucose and fructose from aqueous solutions.
abstract: The kinetics of adsorption by sodium, ammonium, calcium and magnesium forms of zeolite Y from aqueous solutions containing 25% w/v of either one or an equimolar mixture of glucose (G) and fructose (F) have been studied batch-wise at 50 degrees C. The adsorption of aqueous pure G was fast, while that of aqueous pure F depended on the cationic form, approaching that of G on the Mg-Y, and slowing down in the sequence of Mg2+ > NH4+ > Ca2+ > Na+ of the cations. The adsorption behavior from solutions containing both G and F indicated significant hindering effects of F on G on Na-Y. Na-Y and Mg-Y did not exhibit rate-based selectivity, while Ca-Y an NH4-Y adsorbed G faster than F. Addition of CaCl2 to the mixture of Ca-Y and aqueous solution of G and F improved the separation, by hindering the adsorption of F. Addition of NH4Cl to the mixture of the sugar solution and NH4-Y, on the other hand, had a negative effect on the separation. NH4-Y was found to be desorbing about 30% of the adsorbed sugars and this value was found to be around 50% for Ca-Y. Re-adsorption experiments resulted in similar or somewhat higher percentages of amounts adsorbed compared to adsorption on fresh samples. Both NH4-Y and Ca-Y were found to be re-adsorbing around 50% of the sugars they adsorbed on fresh samples.
authors.affiliation: Middle East Technical University, Department of Chemical Engineering, Ankara, 06531, Turkey.
authors.forename: Misket
authors.initials: M
authors.lastname: Heper
authors.forename: Lemi
authors.initials: L
authors.lastname: Türker
authors.forename: N Suzan
authors.initials: NS
authors.lastname: Kincal
mesh_terms: D000327:Adsorption; D017610:Calcium Compounds; D005632:Fructose / Q000493:pharmacokinetics*; D005947:Glucose / Q000493:pharmacokinetics*; D017616:Magnesium Compounds; D000644:Quaternary Ammonium Compounds; D017670:Sodium Compounds; D012996:Solutions; D014867:Water; D017641:Zeolites
chemical_list: D017610:Calcium Compounds; D017616:Magnesium Compounds; D000644:Quaternary Ammonium Compounds; D017670:Sodium Compounds; D012996:Solutions; D014867:Water; D017641:Zeolites; D005632:Fructose; D005947:Glucose