Calcium alginate gels are widely used in the biotechnology, food, and
pharmaceutical industries for cell immobilization, food additives, and controlling the
release of therapeutic agents. Different gelation conditions can lead to different gel
structures which affects the diffusion of solutes in gels, thus mathematical models were
developed to describe diffusion and calcium alginate gel formation.
This thesis on calcium alginate gel formation is divided into two parts, each
with a mathematical model and corresponding experimental study. The objectives of
this thesis were to: 1) Determine the significance of mass transfer resistance and
estimate diffusion and mass transfer coefficients for calcium ions, glucose, and
acetaminophen diffusing into calcium alginate gel. 2) Develop a moving boundary
model of calcium alginate gel formation which predicts the rate of gelation.
To study the significance of mass transfer resistance and to estimate
coefficients, a mathematical model and limiting procedure were developed. This model
and experimental study indicated that mass transfer resistance is significant for calcium
ions and glucose, but not acetaminophen, diffusing into calcium alginate gel. The
limiting algorithm developed to simultaneously estimate the diffusion and mass transfer
coefficients is very sensitive to experimental error, but shows promise in situations with
small numbers of accurate data points taken from non-interacting homogeneous gel
systems.
The model of calcium alginate gel formation was based upon a moving
boundary problem, solved numerically using the implicit method of finite differences,
and programmed in FORTRAN. This study of the rate of calcium alginate gel
formation indicated that increasing the concentration of calcium ions and/or decreasing
the concentration of alginate increases the rate of gelation. The predicted gelation rates
from this mathematical model were in good agreement with the measured gelation rates
based upon stoichiometric binding coefficients, experimental initial concentrations of
calcium ions and alginate, and diffusion coefficients of Ca������ and alginate. / Graduation date: 1997
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34484 |
| Date | 28 April 1997 |
| Creators | Inoue, Shawna K. |
| Contributors | Hoag, Stephen W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
Page generated in 0.0028 seconds