Table 6.

Proposed lignin-based dispersants for various fields.

Lignin Type	Application	Charge Density (meq/g)	Molecular Weight (g/mol)	Modification	References
Hardwood kraft lignin	Cement admixture	−1.60	53,360	Sulfomethylation	[94]
Softwood kraft lignin	Stellar clay, cement, calcium carbonate and titanium dioxide	N/A	N/A	Ozone oxidation	[95]
Softwood kraft lignin	Kaolin suspension	−2.2	14,825	Oxidation	[96]
Lignin N/A	Carbon nanotubes nanofluids	N/A	N/A	As is	[97]
Straw alkali lignin	Dispersant for graphite suspension	N/A	N/A	Carboxymethylation	[98]
Softwood kraft lignin	Dispersant for cement admixture	−3.8	18,299	Oxidation and sulfomethylation	[44]
Hardwood lignin	Kaolin suspension	(−)1.2–3.62	26,700–83,543	Oxidation	[99]
Hardwood kraft lignin	Kaolin suspension	1.80	29,960	Carboxymethylation	[94]
Kraft lignin	Dimethomorph suspension	N/A	18,061–29,201	Grafting poly(ethylene glycol) functionalized with epichlorohydrin using BF3-Et2O	[100]
Wheat straw kraft lignin	Cement admixture	N/A	25,700	Sulfonation	[101]
Wheat straw alkali lignin	Cement admixture	N/A	9688	Hydroxymethylation and sulfonation	[102]
Pinewood alkali lignin	Dye suspension	N/A	11,020	Hydroxypropylation and sulfonation	[103]
Spruce alkali lignin	Multiwalled carbon nanotubes	N/A	14,000	As is	[104]
Softwood kraft lignin	Multiwalled carbon nanotubes	N/A	6500–7000 and 34,000–36,000	Fractionization	[105]
Wheat straw alkali lignin	TiO2 slurry	N/A	17,400–35,700	Sulfomethylation, horseradish peroxide utilization	[106]
Esparto grass lignin	Cement admixture	N/A	10,000	Sulfonation	[107]
Acid precipitated lignin	Cement admixture	N/A	N/A	Sulfonation	[108]

N/A: not available.