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Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Chemical Engineering

Year Degree Awarded

2016

Month Degree Awarded

February

First Advisor

Wei Fan

Subject Categories

Chemical Engineering

Abstract

The increasing demands for transportation fuels and commodity chemicals as well as concerns over diminishing fossil fuel resources have driven research efforts towards the efficient utilization of renewable feedstocks, such as naturally abundant lignocellulosic biomass. Co-impregnation of microcrystalline cellulose with dilute sulfuric acid and glucose catalyzed the formation of a(1→6) branches onto b(1→4) glucan prior to ball-milling and reduce the time needed for ball-milling 4-fold compared to impregnation with acid alone. A three dimensionally ordered mesoporous (3DOm) carbon-based catalyst was developed that rapidly hydrolyzed the water-soluble glucan oligomers to 91.2% glucose yield faster than conventional approaches.

A structure-property relationship was developed for adsorption of saccharides on the carbon catalyst. Van ’t Hoff relationships were derived from adsorption isotherms of glucose and cellobiose and revealed that the adsorption enthalpy increased with increasing chain-length due to the increasing number of CH-π interaction between the saccharides and the carbon surface. Adsorption entropy increased with increasing chain-length and with increasing surface hydrophobicity due to the release of solvated water molecules. The catalyst was optimized for glucose production by tuning the sulfonic to adsorption site ratio, which was easily tuned by controlling the precursors during the diazonium sulfonate functionalization step.

The structure-property relationship of carbon materials with key reaction intermediates has also be studied in an effort to develop a green approach to furan extraction. Formation of HMF from the dehydration of fructose over zeolite catalysts in aqueous phase was studied in a reactive adsorption system using carbon black (BP2000) as an adsorbent. The dehydration of fructose over zeolite beta catalyst in water revealed that selectivity to HMF is largely influenced by the formation of levulinic acid and formic acid as well as humins from HMF. Reactive adsorption with carbon adsorbents was used to increase selectivity by preventing further reaction of HMF. It was found that BP2000 exhibited high selectivity and capacity for the adsorption of HMF from aqueous phase and was similar to that obtained from the reaction system using MIBK as an extraction phase.. The unique adsorption performance of BP2000 is likely due to the large surface area, hydrophobic nature and micropore volume.

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