title: Evaluation of sugar sorption isotherm measurement by frontal analysis under industrial processing conditions.
abstract: This paper evaluates frontal analysis for routine sugar isotherm measurements at industrial conditions, that is concentrations up to 400 kg/m3 and a temperature of 60 degrees C. Sugar isotherms for a gel type cation-exchange resin loaded with metal ions were measured in a HPLC setup equipped with a UV detector. It is shown experimentally that isotherms obtained with large concentration steps (step series method) underestimated the isotherm. The underestimation is larger for larger resin particle size. In contrast, isotherms obtained with small concentration steps (staircase method) yielded correct isotherms. The seldom-mentioned change of the sorbent volume during the course of an isotherm measurement is discussed. It is shown that shrinking of 4% cross-linked resin at high sugar concentration has a negligible effect on the isotherm. Furthermore, the isotherms obtained with staircase frontal analysis agreed very well with those obtained with the independent, though more laborious and time-consuming, adsorption-desorption method. Staircase frontal analysis is shown to be convenient and accurate and is therefore recommended for isotherm measurements covering large concentration ranges.
authors.affiliation: Separation Technology Group, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands. johan.mirjam@tiscali.nl
authors.forename: Johan A
authors.initials: JA
authors.lastname: Vente
authors.forename: Hans
authors.initials: H
authors.lastname: Bosch
authors.forename: André B
authors.initials: AB
authors.lastname: de Haan
authors.forename: Paul J T
authors.initials: PJ
authors.lastname: Bussmann
mesh_terms: D000327:Adsorption; D002241:Carbohydrates / Q000737:chemistry*; D002411:Cation Exchange Resins; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D007221:Industry; D015203:Reproducibility of Results; D013816:Thermodynamics
chemical_list: D002241:Carbohydrates; D002411:Cation Exchange Resins