Table 2 Comparison between various physiochemical methods
Types | Temperature (T) and pressure (P) | %Yield of sugar | Advantage | Disadvantage | References |
|---|---|---|---|---|---|
Steam explosion | T: 180-280 ℃ P: 2.5–7 MPa | Glucose recovery 57–63% | Simple biomass pretreatment | - Generate toxically compounds - Disturb the sustainability of enzymes | |
Liquid hot water | T: 160-240 ℃ P: > 5 MPa | Glucose recovery 73.1% | Simple process Low capital Low maintenance costs Non-corrosion problem High sugar yields | Large amounts of energy are required due to high water consumption | |
CO2 explosion | T: 190 ℃ 20–60 bar CO2 pressure | Glucose yields 80.7% | Cheaper Higher yield Low-temperature requirement | Not relevant for biomass with less moisture amount | |
AFEX process | T: 60-100 ℃ P: 1.7–201 MPa 27% (w/w) ammonia concentration | 42% lignin reduction | Reduce crystallinity and amorphous structure of cellulose | High energy is required to maintain process temperature | [105] |
Wet air oxidation | T: 170-200 ℃ P: 10–20 MPa | 67% Cellulose content, 89% lignin removal, | Simple method Suitable for lignin-enriched biomass residues | High cost to maintain it, cellulose is less affected | [113] |