Designing and preparing high-performance lignin-based dispersants are crucial steps in realizing the value-added utilization of lignin on an industrial scale. Such process depends heavily on an understanding of the dispersion mechanism of lignin-based dispersants. Here, atomic force microscopy (AFM) is employed to quantitatively investigate the dispersion mechanism of a lignosulfonate/silica (LS/SiO₂) system under different pH conditions. The results show that the repulsive force between SiO₂ particles in LS solution is stronger than it is in water, resulting in better dispersion stability. The Derjaguin–Landau–Verwey–Overbeek (DLVO) formula as well as the DLVO formula combined with steric repulsion is utilized for the fitting of the AFM force/distance (F/D) curves between the SiO₂ probe and substrate in water and in LS solution. Based on these fitting results, electrostatic and steric repulsive forces are respectively calculated, yielding further evidence that LS provides strong steric repulsion between SiO₂ particles. Further studies indicate that the adsorbance of LS on SiO₂ (Q), the normalized interaction constant (A), and the characteristic length (L) are the three critical factors affecting steric repulsion in the LS/SiO₂ system. Based on the above conclusions, a novel quaternized grafted-sulfonation lignin (QAGSL) dispersant is designed and prepared. The QAGSL dispersant exhibits good dispersing performance for SiO₂ and real cement particles. This work provides a fundamental and quantitative understanding of the dispersion mechanism in the LS/inorganic particle system and provides important guidance for the development of high-performance lignin-based dispersants.

设计和制备高性能木质素基分散剂是实现木质素工业规模增值利用的关键步骤。该过程在很大程度上取决于对木质素基分散剂的分散机制的理解。在这里，原子力显微镜 (AFM) 用于定量研究木质素磺酸盐/二氧化硅 (LS/SiO ₂ ) 系统在不同 pH 条件下的分散机制。结果表明，LS溶液中SiO ₂颗粒之间的排斥力比在水中强，分散稳定性更好。Derjaguin-Landau-Verwey-Overbeek (DLVO) 公式以及结合空间排斥的 DLVO 公式用于拟合 AFM 力/距离 ( F /D ) SiO ₂探针和基板在水中和 LS 溶液中的曲线。基于这些拟合结果，分别计算静电排斥力和空间排斥力，进一步证明LS在SiO ₂颗粒之间提供强空间排斥。进一步研究表明，LS对SiO ₂的吸附量( Q )、归一化相互作用常数( A )和特征长度( L )是影响LS/SiO ₂空间位阻的三个关键因素。系统。基于上述结论，设计并制备了一种新型季铵化接枝磺化木质素（QAGSL）分散剂。QAGSL分散剂对SiO ₂和真实水泥颗粒表现出良好的分散性能。这项工作提供了对 LS/无机颗粒体系中分散机制的基本和定量理解，并为开发高性能木质素基分散剂提供了重要指导。