Table 1. Comparison of Different LMNPs Isolation Methods (See Also Beisl et al., 2017).23.
| technology | lignin precursor | reported yield | advantages | disadvantages |
|---|---|---|---|---|
| solvent shifting | AL, KL, OS, EHL | 33%–90.9% | · simple process; yields solid and hollow particles | · low solids content (∼1%) |
| pH shifting | AL,KL, EHL | 10% | · high solvent demand; low yields | |
| cross-linking/polymerization | KL, AL, LS, | · controlled size of particles45 | ||
| mechanical treatment | AL, KL | · process known in the pulp and paper industry; simple process; do not use hazardous solvents18 | · nonuniformity of particle size; broad particle distribution range | |
| ice segregation | AL | |||
| template-based synthesis | AL, other lignins | · controlled shape characteristics39,40 | ||
| electrospinning | KL, OS, LS, PL | · low solvent usage | ||
| CO2 antisolvent | KL, OS | 51–88% | · controllability of morphology, size and size distribution; CO2 is nonflammable and nontoxic | · high operating pressure |
| aerosol processing | AL, KL, OS | higher than 60% | · single step process; the absence of liquid byproducts; high yields | |
| dissolution followed by solvent evaporation and redispersion43 | KL | 85% | · possibility to scale-up; simple process | · several steps needed; final product is dispersed in water |
a
AL = alkali lignin, KL = kraft lignin, OS = organosolv lignin, EHL = enzymatic hydrolysis lignin, LS = lignosulfonate, and PL = pyrolytic lignin.