Solventimpregnatedresinsarepromisingfortheremovalofpolarorganiccompoundsfromaqueous streams, buthavelowmass-transferrates. Athoroughunderstandingofthephenomenaoccurringinside the oresofthesolventimpregnatedresinisthereforerequired.Inthisstudyamathematicalmodelwas developed todescribethesimultaneousdiffusionandreaction.Thediffusionwasdescribedusingthe Maxwell¿Stefanapproachtowardsmulti-componentdiffusionandincludedthevolume-expansionof the organicphase.Themodelwasvalidatedusingexperimentaldatafromtheliteratureonthe extractionofphenolbyCyanex923impregnatedinmacro-porouspolypropylene.Themodeldescribed the experimentaldataasfunctionoftemperatureandinitialconcentrationaccuratelywithan R240.96 and aregressedreactionrateconstantwithaconfidence intervalof 76%. Analysisofthemodelresults revealedthatmulti-componenteffectsasdescribedbytheMaxwell¿Stefanmodelwereoflimited importance whereasthevolumeexpansionwasessentialtoaccuratelydescribetheexperimentaldata.@en

Solvent impregnated resins (SIRs) were evaluated for the recovery of pyridine derivatives from an aqueous waste-stream containing also acetic acid and succinonitrile. For this purpose, a new solvent was developed, synthesized and impregnated in Amberlite XAD4. Sorption studies were used to determine the capacity, selectivity and the mass-transfer rate. A high capacity of 21 g 4-yanopyridine (CP) per kg SIR was found, with very high selectivity toward CP over the other solutes of at least 570. A modified Langmuir equation could describe the equilibrium sorption isotherm. Both the linear driving force model and a Fickian diffusion model were evaluated. The Fick-model described both regeneration and loading best. The CP-diffusivity through the solvent phase was estimated at 6.53 10 13 ± 2.5% m2 s 1. The model was validated using fixed-bed column experiments. The R2 values for this model ranged between 0.94 at a flow rate of 5 mL/min and 0.99 at a flow rate of 1 mL/min during the loading cycle. Due to mass-transfer limitations the breakthrough profiles were broad and breakthrough occurred after 5 or 23 bed volumes, for flow rates of 5 and 1 mL/min, respectively. Both acetic acid and succinonitrile broke through immediately due to the very high CP-selectivity of the SIR.@en