دانلود رایگان مقاله ساختارشکنی چوب ذرت توسط بخار قبل انفجار

ABSTRACT

In this work, acid-catalyzed steam explosion was carried out as a pretreatment to hydrolyze hemicellulose and increase the enzymatic digestibility of corncob. Pretreatment conditions were varied to achieve structural alterations in a wide range: type of acids (sulfuric acid and oxalic acid), acid concentration (0.1–1.5 wt.%) and pressure (1.0–1.8 MPa). The pretreated residues were analyzed by chemical analysis, surface area measurement and x-ray diffraction. Biomass and cellulose crystallinity, lignin content and specific surface area were obtained and their correlations with sugar conversion were compared. The results suggested that these parameters were coupled together and they explained in part the diversity of the literature data that improves understanding of steam explosion pretreatment.

4. Conclusions

Acid-catalyzed steam explosion pretreatment decreases cellulose crystallinity. However, biomass crystallinity instead of cellulose crystallinity is correlated with sugar conversion at 72 h. While removal of hemicellulose exposes more cellulose fibers to enzymes, the enrichment of lignin in the solid residues inhibit hydrolysis. With similar specific surface areas, oxalic acidimpregnated samples show lower sugar conversions than sulfuric acid-impregnated ones due to their higher biomass crystallinity and lignin content. By applying correlation curves between biomass recalcitrant parameters and enzymatic hydrolysis, the interactive nature between these parameters are revealed that deepens understanding of steam explosion pretreatment.