Degree Type

Dissertation

Date of Award

2006

Degree Name

Doctor of Philosophy

Department

Chemical and Biological Engineering

First Advisor

Brent H. Shanks

Abstract

This research has provided a fundamental analysis of the use of novel separation and catalyst techniques for saccharification of lignocellulosic tissues. Separation techniques focused on providing a feedstock that was more amenable to hydrolysis. Catalyst development focused on solid acid materials that would provide processing advantages, cost reductions, and waste reduction. A mechanical separation technique was used on corn stover to separate the parent material into two streams with improved processing characteristics. The desire was to produce a material that was easier to hydrolyze in addition to producing a material with enhanced fiber character. The separation technique was effective; however, the material streams did not have significantly different hydrolysis characteristics, which made further development of this technique unattractive. A second separation process that was evaluated was the hydrothermal treatment of distiller's dry grain (performed at Purdue University). This treatment was effective in producing a stream of soluble oligosaccharides that were amenable to hydrolysis to monosaccharides. Acid-functionalized mesoporous silica was synthesized and tested in a model system as a cellobiose hydrolysis catalyst, as well as a catalyst for the hydrolysis of solubilized oligosaccharides generated from distiller's dry grain hydrothermal treatment. These materials were also evaluated with monosaccharides to determine the catalyst activity towards undesirable degradations reactions. The acid-functionalized silica materials were effective catalyst materials with performance similar to homogeneous catalyst materials. These materials were robust enough to be utilized in real systems without severe reduction in catalyst activity. Acid-functionalized silicas were particularly attractive due to low degradation rates of desirable products. Distinct pH controlled kinetic regimes were shown to be responsible for the low degradation rates and these materials produced ideal pH for desirable degradation kinetics. The chemistry of aqueous phase systems was discussed and several key attributes (leveling, proton mobility, and the ion product) were identified as critical considerations for future catalyst development for use in aqueous systems.

DOI

https://doi.org/10.31274/rtd-180813-10979

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu

Copyright Owner

Jason Alan Bootsma

Language

en

Proquest ID

AAI3229053

File Format

application/pdf

File Size

115 pages

Share

COinS