Table 4 Comparison of CNCs preparation methods used in literature and in this study
Treatment methods | Raw material | Characteristics of prepared CNCs | Process overview | References |
|---|---|---|---|---|
Sulfuric acid hydrolysis | BEKP | CrI: 73%; length: over 200 nm; Shape: nanofibril-like | Yield 70%; treatment: H2SO4 50–64 wt% at 35–80 °C; requiring acid corrosion resistant equipment; great quantity of acid wastewater | Chen et al. (2015) |
Sulfuric acid hydrolysis | BEKP | CrI: 66.1–81.9%; width: < 50 nm; length: different size; Shape: rod-like | Highest yield 53.9%; treatment: H2SO4 44.1 wt% at 80 °C; requiring acid corrosion resistant equipment, great quantity of acid wastewater | Aguayo et al. (2020) |
TEMPO treatment | BSKP | CrI: 81–83%; width: 3.5 nm–3.6 nm; Length: 185 nm–292 nm | Treatment: TEMPO/NaBr/NaClO system in water at pH 10; requiring alkali corrosion resistance equipment; alkaline wastewater containing TEMPO | Zhou et al. (2018) |
Cellulase treatment, then sulfuric acid hydrolysis | BSKP | CrI: 75.3%; Particle size distribution: 80 nm–500 nm; Shape: needle-like | Yield 35.3%; treatment: cellulase at 55 °C for 6 h, then H2SO4 30–50 wt%; requiring acid corrosion resistant equipment; sugar solution and acid wastewater | An et al. (2016) |
Endoglucanase; sulfuric acid | Wood Pulp | CrI: 81–83%; Particle size distribution: 125.2 nm–147.7 nm; Shape: needle | Yield 13.2–16.9%; treatment: cellulase at 50 °C for 72 h and H2SO4 64 wt% at 45 °C; requiring acid corrosion resistant equipment; sugar solution and acid wastewater | Dai et al. (2018) |
Endoglucanase | BEKP | width: 6 nm–10 nm; length: 400 nm–600 nm | Treatment: cellulase at 50 °C, 72 h; commercia EG-GH5-BA and EG-GH7-TL; sugar solution | Siqueira et al. (2019) |
Glycerin; cellulase; xylanase | EP | Size: 30 nm Shape: spherical | Yield 13.6%; optimal reaction conditions: 50 °C, 72 h; commercial cellulase and xylanase; sugar solution | Chen et al. (2018) |
cEES cellulase system | EDP | CrI: 87.3–93.4%; Length: < 500 nm Shape: fusiform | Yield 15.7%; reaction conditions: 50 °C, 72 h; engineered cellulase cEES; sugar solution | This study |