Impact Of CaO₂ Synergy HCL Pretreatment On Hydrolysis Of Wheat Straw

Currently, straw pretreatment methods of straw-to-ethanol conversion neither need hightemperature, nor are inefficient, nor cost too much money. Based on this, this paper usedCaO2 as the regent of pretreatment. And the aim of this paper was researching the impact ofCaO2 or CaO2+HCl pretreatment on hydrolysis of wheat straw at low-middle temperature.The results showed that, a higher delignification rate of CaO2 pretreatment was reachedwhen raise pretreatment temperature or regent. The delignification rate was 79.52% whenthe conditions were 8 %( w/w) CaO2 at 126℃ for 120 min. At this point, lignin content inpretreated wheat straw was 2.74 g/100gDM. And reducing sugar recovery yield was 28.35g/100DM. When pretreatment time was 180 min, contents of cellulose, hemicellulose, andlignin in wheat straw were 21.53 g/100gDM、8.27 g/100gDM、5.44 g/100gDM bypretreatment at 120℃with 4% CaO2. 59.34% of lignin was removed. Total reducing sugaryield in hydrolysate was 5.97g/100 GDM, and glucose recovery rate in wheat straw was65.39%. Compared with H2O2 pretreatment at the same conditions, delignification rates ofCaO2 pretreatment were 13.75% higher at 60℃ , 37.74% higher at 80℃ and 20.33% at120℃. It proved that at low-middle temperature the delignification effect of CaO2 was betterthan that of H2O2. Compared with CaO2 pretreatment, hydrolysis rate of hemicellulose,reducing sugar yield in hydrolysate and and glucose recovery rate by two-step pretreatmentwith CaO2+HCl were better. When the first step conditions were 4%(w/w) CaO2 at120℃ for 180 min and the second step conditions were 1.5%(w/w) HCl at 120℃ for30min，the hydrolysis results were the best. Contents of cellulose, hemicellulose, and ligninafter pretreatment were 24.97 g / 100 gDM, 5.52 g / 100 gDM, 6.54 g / 100 gDM. Rates ofdelignification and hemicellulose hydrolysis were 51.12% and 67.14%. Total reducingsugar yield in hydrolysate was 14.65g/100 GDM, and glucose recovery rate in wheat strawwas 75.86%. Compared CaO2 pretreatment with CaO2+HCl pretreatment, effect ofhydrolysis of latter is better, considering reducing sugar yield in hydrolysate and glucoserecovery.