Doctoral Dissertations


Xiaomin Zhang

Keywords and Phrases

Concentration overshoot phenomena; Charge distribution


"An analysis based on a macroscopic continuum rigorous model of the conditions necessary for the development of an overshoot in the concentration of a charged bioactive macromolecule in the adsorbed phase of charged adsorbent particles is presented, and the parametric sensitivity of the concentration overshoot phenomenon with respect to its enhancement or suppression is studied. Practical implications of this phenomenon on operational policies and configurations of ion-exchange chromatography (IEC) systems for the separation of bioactive macromolecules are indicated.

Molecular dynamics (MD) modeling and simulation studies are performed and their results indicate the physical mechanisms that are relevant and actively involved in the transport and adsorption of charged macromolecules in IEC systems, as well as their relative importance. The results obtained from the MD simulations show that when a charged macromolecule is adsorbed, it is restrained by a strong dominant Coulombic interaction and is trapped by a hydration layer adjacent to the surface and these lead to zero lateral displacement of the adsorbed macromolecule. It is shown through the development of a novel method of analysis that from MD modeling and simulation studies the values of the pore radius and length that could provide efficient separation of macromolecules could be estimated, and could then be used to guide the design and construction of porous adsorbent particles whose pore surf aces are charged.

Also, dextran polymer porous layers attached on a base matrix are constructed by MD modeling and simulation studies and these polymer porous layers significantly increase the surface area in porous matrices for the attachment of affinity groups/ligands, as well as the adsorption capacity of the adsorbent particles employed in IEC systems"--Abstract, page iv.


Liapis, Athanasios I.

Committee Member(s)

Wang, Jee C.
Crosser, Orrin K.
Neogi, P. (Partho), 1951-
Hale, Barbara N.


Chemical and Biochemical Engineering

Degree Name

Ph. D. in Chemical and Biological Engineering


University of Missouri--Rolla. Department of Chemical and Biological Engineering


Accompanying CD-ROM, available at Missouri S&T Library, contains Appendix B, which contains the FORTRAN CODE of all the projects studied in this work. The programs are of *.f file format and can be opened in any text editor.


University of Missouri--Rolla

Publication Date

Summer 2005

Journal article titles appearing in thesis/dissertation

  • Analysis and parametric sensitivity of the behavior of overshoots in the concentration of a charged adsorbate in the adsorbed phase of charged adsorbent particles: Practical implications for separations of charged solutes
  • Molecular dynamics simulation studies of the transport and adsorption of a charged macromolecule onto a charged adsorbent solid surface immersed in an electrolytic solution
  • Molecular dynamics simulation studies of the conformation and lateral mobility of a charged adsorbate biomolecule: Implications for estimating the critical value of the radius of a pore in porous media
  • Construction by molecular dynamics modeling and simulations of the porous structures formed by dextran polymer chains attached on the surface of the pores of a matrix: Characterization of porous structures


xiii, 196 pages; CD-ROM

Note about bibliography

Includes bibliographical references.


© 2005 Xiaomin Zhang, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type




Subject Headings

Ion exchange chromatography
Molecular dynamics

Thesis Number

T 8825

Print OCLC #


Electronic OCLC #


Link to Catalog Record

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