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James B. Falabella B.S. Chemical Engineering
2001 Northeastern University
M.S. Chemical Engineering
2003 Northeastern University
jfalabella@chbe.gatech.edu |
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Projects:
1. Partitioning of VOCs in aqueous salt solutions and other dilute systems.
The partitioning of
volatile organic compounds between a vapor phase (air) and an aqueous phase is
of interest in a number of applications, including the control of unwanted
releases from wood pulping operations, and the removal of organic pollutants
from contaminated sites. We are using
headspace gas chromatography to measure Henry’s constants of VOCs in water
containing salts and polymers (such as lignin). Our past work has shown that
simple systems containing a salt and a VOC (methanol) can yield Henry constants
that are of the same magnitude as those measured in real black liquor samples
from a pulping process. We are currently extending these measurements to
aqueous systems containing other VOCs from the pulping process, such as acetone
and methyl ethyl ketone. We hope to provide accurate and reliable data for the
design of closed-loop systems for the paper industry, and also provide data for
atmospheric pollution models.
We have also
developed a dilute solution model for the calculation of Henry’s constants of
systems containing a VOC, water and a salt over a range of temperatures from
ambient temperature to the critical temperature of water. Further refinements of the model and its
limitations are being investigated.
2. Prediction of amino acid crystal purity
The solubility of mixtures of amino acids in water is of interest in the design of crystallization processes for the recovery of amino acids from fermentation broths. However, there have been very few studies involving two or more amino acids in water and, in addition, these studies have often relied on obtaining the liquidus curve by the addition of an excess amount of one amino acid to a solution containing the other amino acid until no more of the added amino acid dissolved. Only the liquid phase was then sampled. We have shown that this method does not yield equilibrium data, especially when the solutes have similar structure and/or functionality. In this case, the two solutes may deposit simultaneously in the crystal lattice, and recrystallization can lead to the formation of solid solutions.
We have also developed a model for the estimation of the solidus curve (and hence the crystal purity) when solid solutions are formed. An interesting observation is that the solid phase is highly nonideal, even when the two amino acids are very similar. We are currently attempting to extend this model to other isomorphic systems, including those related to wax depositon.
Publications:
- Chai, X-S, Falabella, J.B., Teja, A.S., A Relative headspace method for Henry's constants of volatile organic compounds, Fluid Phase Equilibria, 231, 2005, 253-259
- Falabella, J.B., Kizzie, A.C., Teja, A.S., Henry’s constants of gases and volatile organic compounds in aqueous solution, Fluid Phase Equilibria (John Prausnitz Edition), 241, 2006, 96-102.
- Falabella, J.B., Nair, A, Teja, A.S., Henry's constants of 1-alkanols and 2-ketones in salt solutions, Journal of Chemical and Engineering Data, 51, 1940 - 1945.
Last Modified: July 7, 2005