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| Pretreatment methods | Biomass | Required pretreatment condition | Changes after pretreatment | Ref. |
|
| Alkaline hydrogen peroxide | Wheat straw | 0.2 Mol/l NaOH at 30°C for 5 hr
20 mg H2O2/g biomass
50°C for 7 hrs | 42.7% of lignin removal | [17] |
| Hydrogen peroxide- acetic acid (75% HPAC) | Poplar | 30%, H2O2 & 99%, acetic acid in 1 : 1 ratio
100 mM H2SO4 as catalyst (1 : 10, w/v) 80°C, 2 hr | Decrease in lignin concentration from 28.2% to 3.1%
Glucan content increased from 40% to 67.2%, with 11.8% glucan removal | [19] |
| Alkaline hydrogen peroxide treatment | Bamboo | 3%, H2O2, 100°C, 2.2% NaOH | 76.5% of glucan, 56% of xylan recovered, & 79.25% of lignin removal | [20] |
| HPAC | Bamboo | 30% H2O2: CH3COOH (1 : 1, ) | Reducing sugar yield increases by more than 1.3-fold while cellulosic content increases by 1.7-fold | [22] |
| H2O2 + H3PO4 (PHP) | Wheat straw | 74.92 gm H3PO4 (85%, ) & 5.08 gm H2O2 (30%, ) | 54.1% of lignin removal with 92.4% of sugar conversion | [27] |
| HPAC | Maize straw, sugarcane bagasse, Eucalyptus bark | 10 ml HPAC (1 : 1, v/v), incubated at 80°C for 2 hr | Cellulose crystallinity increases from 34% to 53% | [39] |
| Combined process of acetic acid and H2O2 (AC-HPAC) | Poplar | 5%, acetic acid with solid to liquid ratio of 1 : 10
100 ml HPAC (80%, ) & 100 mM H2SO4 at 60°C for 2 hr. | Glucan content increased from 42.1% to 54.5% with 85.8% glucan content | [40] |
| Alkaline hydrogen peroxide+ supercritical CO2 + ultrasound | Sugarcane bagasse | Pressured CO2–20.6 Mpa, 453 K temperature for 1 hr, 0.6% H2O2 treatment for 9 hr and 4 hr ultrasound retention time | 97.8%, of glucose recovery | [41] |
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