Table 1.

Preparation of Lignin Nanoparticles by Using Water as Anti-solvent.

Lignin Source	Solvent	Diameter (nm)	Zeta Potential (mV)	Morphology	Mechanism	Advantage	Disadvantage	References
kraft lignin, enzymatic hydrolysis lignin	THF	200–500 190–590 ---	−60 --- ---	spherical, hollow nanosphere	self-assembly π–π interaction	more stable, simple method	uncontrollable size, toxic solvent	[47,48,49]
soft wood kraft lignin	mixtureof THF/ EtOH/ H2O	around 200	−40	colloidal spherical	self-assembly	large scale production, solvent recyclable	energy consumption, complexity, incoherence	[50]
alkaline lignin	pTsONa solution	80–230	−28.6	quasi- spherical	self-assembly	high solubility, no organic solvents	irregular morphology, instability	[51]
kraft lignin	ethanol	63.35	---	hollow sphere	self-assembly π–π interaction	green solvents, simple operation	no research on stability	[52]
corn biomass, softwood alkali lignin, high purity lignin	acetone/water	50–250 80–104 40–200	--- --- −18.1	spherical	self-assembly	valorization of corn biomass, tunable surface properties	complex process, non-green solvent	[53,54,55]
kraft lignin	dioxane	200–400	---	hollow sphere	self-assembly π–π interaction	more uniform size	toxic organic solvent	[56]