Table 3.
Effect of inorganic salts and their mass fractions on the [C2mim]Cl/water/salt pretreatment and [C2mim]Cl recovery
| Inorganic salt | Mass fraction (%) | Solvent pH | Lignin removal (%) | Sugar yield (%)a | IL recovery (%) |
|---|---|---|---|---|---|
| KCl | 2 | 4.31 | 2.02 (± 0.04) | 17.13 (± 0.47) | – |
| K2SO4 | 2 | 5.36 | 2.44 (± 0.13) | 18.91 (± 1.11) | – |
| KH2PO4 | 2 | 5.88 | 2.20 (± 0.06) | 19.55 (± 0.54) | – |
| K2HPO4 | 2 | 9.91 | 13.94 (± 1.18) | 27.96 (± 0.98) | 71.25 (± 1.24) |
| K3PO4 | 2 | 13.60 | 45.76 (± 2.25) | 64.33 (± 2.64) | 98.14 (± 0.77) |
| K2CO3 | 2 | 12.86 | 72.38 (± 1.67) | 84.99 (± 0.51) | 88.53 (± 0.69) |
| K2CO3 | 1 | 12.16 | 70.49 (± 1.40) | 75.17 (± 2.20) | 95.95 (± 1.23) |
| K2CO3 | 3 | 12.97 | 78.94 (± 0.78) | 88.67 (± 1.28) | 96.28 (± 2.51) |
| K2CO3 | 5 | 13.22 | 81.45 (± 1.29) | 80.32 (± 1.37) | 92.67 (± 0.40) |
| K2CO3 | 7 | 13.46 | 93.70 (± 2.43) | 92.07 (± 1.66) | 94.32 (± 0.44) |
| K2CO3 | 9 | 13.69 | 85.39 (± 1.55) | 90.61 (± 0.72) | 94.54 (± 2.10) |
Mass fraction of [C2mim]Cl was 40%, pretreatment temperature was 110 °C, and pretreatment time was 1 h
aEnzymatic hydrolysis time was 72 h