A preliminary investigation on the microwave methods for determining hot water solubles and Klason lignin in woodI
| Autor: | Wen-xuan Huang, 黃文宣 |
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| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 A microwave extraction method is proposed as an alternative to the conventional method for determining the hot water solubles and Klason lignin of wood. In this alternative method, experimental results indicate that 100 mL water can be heated to boiling point in only 75 seconds under the microwave radiation. Hence, only 15-20 minutes are required to complete the extraction procedure for Liquidambar formosana Hance, Swietenia macrophylla Jacq, Taiwania cryptomerioides and Cunninghamia lanceolata (Lamb) Hook at the same level. In general, a 15 min microwave heating has the potential to be an alternative to the conventional method in which requires 3 hours for the hot water solubles determination. For Klason lignin determination, a 20 min microwave heating in 3% sulfuric acid can speed up the acid hydrolysis, which leads to the similar Klason lignin contents. Due to the almost identical acid soluble lignins and color of Klason lignin powders presented, it is hopefully to use microwave method replacing the conventional method. Acid soluble lignin contents determined with UV spectroscopy demonstrated that no differences between conventional and microwave methods for two softwood species, and slight variations present between two hardwood species. Additionally, no significant difference can be seen for the appearance of 3% H2SO4 wood meal treated with conventional and microwave methods by the photomicrographs of scanning electron microscopy. In general, time-saving is the main advantage of microwave method for determining hot water solubilities and Klason lignin in 4 Taiwan wood species. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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