| Summary: | 碩士 === 國立臺灣師範大學 === 化學系 === 106 === Herein, this study has discovered mesophase pitch (MP) carbonaceous material derived from petroleum waste, can be modified with high surface coverage of acid functional groups on the edges of layered structure, which could be further used as hydrolytic catalysts for hydrolyzing cellulose. This close proximity of acid moiety on aforementioned carbon materials resembles the center of hydrolysis enzymes, which composes of two close carboxylate groups, such as glycosidase. Chemical modification on carbon materials was listed as following: (1) sulfonic acid modification (MP-SO3H), (2) hydrothermal treatments of MP-SO3H (MP-SO3H-HT), (3) nitric acid modification (MP-COOH), and (4) sodium hypochlorite modification (MP-Oxy) and surface properties were characterized both qualitatively and quantitatively. Quantification of acid functionality was determined by the acid-base back-titration and the distance between layered structure was calculated from the powder X-ray diffraction pattern, and surface area can be characterized from nitrogen sorption study. Furthermore, acid groups were observed to be mainly modified on the edge of the graphitic nanostructure for MP structure owing to the diminishing of aliphatic carbon in spectra of 13C DP/MAS solid-state NMR analysis. In addition, hydrolytic performance was carried out by using MP-SO3H with a catalytic ratio of 4.8 mol% (acid groups/cellulose) for hydrolyzing cellulosic polymer of peak molecular weight (7,374 Da) and the results have shown the glucose yield can reach up to 44 mol%. On the other hand, only lower than 3 mol% of glucose yield could be observed during the hydrolytic reaction of leaching sulfonic groups and it further suggested that MP-based catalysts with acidic functionalities exhibited hydrolytically stable, which could lead the entire catalytic processes more effectively and eco-friendly.
In addition, we serendipitously discovered that MP-SO3H-HT exhibited high carbon dioxide uptake upto 28 wt% and it might be attributed to layered structure of carbonaceous material, which was different from the adsorption energetics of porous materials reported previously. Hence, it suggested that this aforementioned carbon material can be potentially employed for the capture and storage of carbon dioxide in the future.
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