ABSTRACT
Zeolites adsorb biopolymers on their surface and may be suitable as a new type of chromatographic carrier material for proteins, nucleic acids, and their conjugates. We report here various parameters that influence the adsorption of biopolymers on synthesized zeolites with regard to the Si/Al2 ratio and three-dimensional structure. There are three physicochemical principles that may underly the adsorption: 1) below the isoelectric point (pI), mainly Coulombic attraction similar to ion-exchange chromatography; 2) at pI, hydrophobic interactions (a kind of van der Waals attraction) plus the three-dimensional mesopore structure; and 3) above pI, the sum of the Coulombic repulsion and attraction forces, such as the hydrophobic interaction, and also substitution reaction of water on the Al molecule with a protein amino-base. At high Si/Al2 ratio in the presence of a small amount of Al and with mesopores between the zeolite particles, maximal adsorption was seen at pI and was suggested to be dependent on the number of hydrophobic interaction points on the mesopores, and their morphology. The application of zeolites to biochemistry and biotechnology is also discussed.
ABSTRACT
Organic structure-directing agents are necessary to the formation of defined zeolitic structures; doing without the organic component can simplfy the reaction immensely. Such a transformation, of protonated magadiite to a new layered silicate, is reported herein. The picture shows the XRD patterns of as-prepared protonated magadiite and the product after simple hydrothermal treatment at two different temparatures. After calcination (500 °C) the final material has a surface area of 457 m(2) g(-1).
