Читать книгу Handbook of Biomass Valorization for Industrial Applications - Группа авторов - Страница 36

Alkaline chemicals like Na, K, Ca, and NH₄OH are much required for preliminary treatment of lignocellulosic biomass. Using an alkali allows the ester and the glycosidic side chain to degrade, resulting in structural lignin modification, swelling of cellulose, partial cellulose recrystallization [53–55] and partial hemicellulose solvation. NaOH has been widely researched for several years [56, 57], and the destruction of the biomass lignin structure has been shown to improve the user-friendliness of cellulose enzymes [51, 58, 59]. Lime is another alkali and has been used for biomass pre-treatment. Corn stover, turn grass, is a lignocellulosic feedstock, which has shown benefit from this pre-treatment process of straw bagasse, barley, and rice [60, 61–64].

The efficacy of multiple alkaline solutions by analyzing hemicellulose wheat straw delignification and dissolution. They observed that 1.5% NaOH for 144 h at 20 °C was the optimum state, resulting in 60% lignin release and 80% hemicellulose release. Alkaline pre-treatment conditions are generally less severe than most pre-treatments. It may be conducted at atmospheric temperature, but it needs longer pre-treatment periods compared to more temperatures. The alkaline method includes soaking biomass at a target temperature in alkaline solutions and mixing. The benefit of alkaline pre-treatment for specific period is that a given quantity of biomass lime cost needed is the less among alkaline treatment methods [65].