Continuous separation of amino acids from aqueous solution in a flow-type adsorber by molecular sieve adsorbents

Abstract

The separation of various amino acids from aqueous solutions using microporous and mesoporous molecular sieves is discussed on the basis of their adsorption isotherms and breakthrough curves. Characterization of the molecular sieves before and after the adsorption process reveals that the adsorbed amino acids are mainly located inside the pores, from where they can be extracted with water and mineral acids. While MCM-41 exhibits a low adsorption capacity for both amino acids, high amounts of phenylalanine and leucine are adsorbed on HBeta and HZSM-11. The preferential adsorption of leucine on the medium-pore zeolite HZSM-11 at low coverage can be used to separate leucine from a mixture of leucine and phenylalanine, while the large-pore zeolite HBeta can be employed to separate phenylalanine from the same mixture.