The study aimed to reveal the reason why carboxymethylated lignin (CML) had better dispersion properties than sulfomethylated lignin (SAL). It was found that hydrophilic property of CML was weaker than that of SAL by measuring the amount of hydrophilic group of CML and SAL

relative molecular weight and pure water contact angle on lignin coating. The measured adsorption isotherms of two lignin dispersants on carbendazim particles showed that the adsorption capacity of CML was higher than that of SAL

indicating that CML was easier to be absorbed on carbendazim particles than SAL. It was also found that the adsorption ability of CML was larger than that of SAL under the application of the Langmuir and Freundlich adsorption isotherm equations. It indicated that the adsorption affinity between weak hydrophilic CML and pesticides was stronger

and the adsorption between lignin and pesticides may be based hydrophobic adsorption. Further more

through simulate calculating the π-π force between lignin dispersants and carbendazim

it was found that the CML was easier to form a stable π-π effect with pesticides and to promote the adsorption. Due to the stronger adsorption affinity between CML and pesticides

the absorption capacity of weaker hydrophilic CML was higher

and thus CML can improve the Zeta potential of carbendazim particles

showing better dispersion properties.