High Specific Interaction of Polymers with the Pores of Hydrophobic Zeolites

Abstract

Poly(ethylene oxide) (PEO), poly(acrylic acid) (PA), dextran, and some oligomeric saccharides were found to be adsorbed from the aqueous phase on a dealuminated FAU-type zeolite (Si/Al = 110). PEO was also adsorbed on a MFI-type zeolite (Si/Al > 1000), but dextran was not. Inulin and levan were excluded from the FAU-type zeolite. Addition of ethanol (dextran) or increase of pH (PA) caused a strong decrease of the adsorption equilibrium. The Fickian diffusity D of the trimer of dextran (isomaltotriose, M w = 504) related to that in the aqueous bulk phase D 0 was D/ D 0 = 10-3 and decreased to D/D 0 = 10-8 at M w = 40 000. D/D 0 values for PEO (M w = 9000, 20 000, and 40 000) in the FAU zeolite were situated between 2 and 5 × 10-7. The high specific interaction indicates that the polymer not only is deposited on the surface of the zeolite crystal but must penetrate to some extent into the pores. The FAU zeolite can selectively adsorb oligomers and polymers containing α(1−6) glycosidic linkages (raffinose, stachyose, isomaltotriose, dextran) while those built up by β(1−6) or α,β(1−4) bonds are sterically excluded.

Adsorption of polypropylene from dilute solutions on a zeolite column packing

“…We assume that the retention of polypropylene is connected only with a partial penetration of polymer chains in approximately linear conformation into narrow pores of zeolites. The penetration of polymer chains into zeolites was also assumed by Buttersack et al [24], although the hydrodynamic diameters of the polymers in the mobile phase were up to 32 times larger than the pore diameter of the used zeolite. This assumption was recently supported by theoretical simulations performed by Hermsen et al [34].…”

“…Buttersack et al [24] have described total adsorption of polyethylene oxide, dextran, and poly(acrylic acid) on zeolites from water and Matsui et al [25] have observed adsorption of proteins and nucleic acids on zeolites. Matsui et al [25] supposed interactions of the biopolymers only with the external surface of the zeolite crystals, while Buttersack et al [24] assumed that the extent of pore penetration may range from docking to inclusion of the whole polymer chain.…”

Adsorption properties of BEA zeolites and their aluminum phosphate extrudates for purification of isomaltose

“…This could also explain the strength of interaction and slow desorption rate in zeolite crystals. Buttersack et al (1996) discuss this phenomena on FAU zeolites and observed a difference between ad-and desorption kinetics.…”

“…Buttersack et al (1996) interpreted slow diffusion in FAU zeolites as a method of docking and pore penetration. But he also suggested another mechanism, the docking and surface attachment.…”

Synthesis and properties of methacrylic acid based hydrogels modified with zeolites

“…Eksperimentalni rezultati (visok sorpcioni kapacitet, selektivnost i spora difuzija) pokazuju da postoji mogudnost da su specifične hidrofobne interakcije kompenzovale entropijski nepovoljnije, izdužene, konformacije lanaca, koje mogu da se potpuno ili delimično smeste u pore zeolita. U prilog tome idu i slededi rezultati: prvi, da se poli(akrilna kiselina) čiji je prečnik ispruženog lanca 0.7 nm, adsorbovala na FAU zeolitu sa veličinom pora od 0.74 nm, a nije na MFI zeolitu sa porama od oko 0.55 nm, i drugi da je adsorpcija favorizovana u kiseloj sredini kada PAA nije u disosovanom obliku, dok se u baznoj sredini dešava potpuna desorpcija [172].…”