US EPA

3579948 

Journal Article 

Fractional separation of hemicelluloses and lignin in high yield and purity from mild ball-milled Periploca sepium 

Xu, F; Sun, RunC; Zhai, MeiZhi; Sun, JinXia; She, D; Geng, ZC; Lu, Qi 

2008 

1 

Separation Science and Technology
ISSN: 0149-6395
EISSN: 1520-5754 

43 

11-12 

3351-3375 

10.1080/01496390802063721 

WOS:000258689100020 

A novel three-step procedure for separation of hemicelluloses and lignin with high yield and purity was proposed in this study, where wood is mildly milled and successively extracted to produce three hemicellulosic and lignin fractions representing the total hemicelluloses and lignin in wood. The sequential treatments of the mild ball-milled Periploca sepium with 80% aqueous dioxane containing 0.05 M HCl at 85 degrees C for 4 h, DMSO at 85 degrees C for 4 h, and 8% NaOH at 50 degrees C for 3 h resulted in a total release of over 85% of the original hemicelluloses and 86% of the original lignin. In particular, approximately 36% of the original hemicelluloses and 50% of the original lignin were separated during the first mild acidolytic hydrolysis process after low intensity milling. The structure of the acidic dioxane-, DMSO-, and alkali-soluble hemicellulosic and lignin fractions were elucidated using wet chemical analysis, FT-IR, and solution-state (1)H, (13)C, and (31)P NMR techniques. Results showed that both the mild ball milling and the mild acidolysis under the conditions given did not affect the separated lignin macromolecular structure. On the other hand, the mild acidolytic hydrolysis condition did cause substantial hemicellulosic depolymerization exception for a significant cleavage the ether linkages between lignin and hemicelluloses. The acidic dioxane-soluble lignin fraction was structurally different from the DMSO- and alkali-soluble lignin preparations and may originate mainly from the primary wall, while the alkali-soluble lignin preparation was mainly released from the secondary wall of Periploca sepium. Furthermore, it was found that the acidic dioxane-soluble hemicelluloses mainly contained more branched and less acidic arabinoxylans, and the 8% NaOH-soluble hemicellulosic fraction H(3) was both less branched and less acidic in structure, whereas the DMSO-soluble hemicelluloses were more acidic but less branched and consisted mainly of 4-O-methylglucuronoarabinoxylan. 

ball millings; hemicelluloses; mild acidolysis; native lignin; Periploca sepiums; (1)H; (13)C; (31)P NMR