Structure-Adsorption Behavior-Dispersion Property Relationship of Alkyl Chain Cross-Linked Lignosulfonate with Different Molecular Weights.

Abstract

The structure–adsorption behavior–dispersion property relationship plays a key role in designing a dispersant or surfactant, such as a coal–water dispersant and a water-reducing agent. In this work, was classified into three fractions with narrow molecular weight distributions via the ultrafiltration method. The adsorption behavior of these three fractions was tested via a quartz crystal microbalance with dissipation monitoring, which showed that the adsorption amounts of the three fractions were far higher than that of sulfomethylated lignin. Fraction-1, with the lowest molecular weight, exhibited the greatest adsorption amount on a Au surface under salt-free conditions. This result illustrates that the alkyl chain is more effective for dispersants with low molecular weight to improve its adsorption amount. Fraction-3, with the highest molecular weight, exhibited the greatest adsorption amount on a Au surface under salt-added conditions. This result further illustrates that both the alkyl chain and salt are positive factors for improving the adsorption amount of dispersants. More importantly, the dispersion stabilization of the TiO2 slurry was significantly improved using the alkAL-S fractions, especially Fraction-3. Based on these results, the alkyl chain cross-linked of lignosulfonate is a promising approach for the industrial applications of lignin as an applicable dispersant.