不同相对分子质量对接枝磺化木质素水煤浆分散剂吸附分散性能的影响

Effects of molecular weight of grafted sulfonated lignin on its dispersion and adsorption properties as a dispersant for coal water slurries

采用接枝磺化缩聚法制备了不同相对分子质量碱木质素系水煤浆分散剂(GCL3J系列),研究相对分子质量对水煤浆吸附分散性能的影响。流变学研究结果表明,具有三维空间网络结构的GCL3J分散降黏性能均优于具有线性结构的萘系分散剂。等温吸附和Zeta电位测试结果表明,GCL3J在煤粒表面的吸附特征属于Langmuir型单分子层吸附,随着相对分子质量的增加,其在煤粒上的吸附量逐渐减少,吸附作用力逐渐增强,并逐渐以疏水作用吸附为主。中等相对分子质量的GCL3J-3(Mw为31500 Da,特性黏度为8.06 mL/g)在煤粒表面吸附后,具有适宜的吸附量和吸附强度,且负电性最高,对水煤浆具有最优的分散降黏作用。

A series of grafted sulfonated lignin-based dispersants, GCL3J series with different molecular weight, were prepared by graft copolymerization, sulfonation and polycondensation reactions using alkali lignin as the main raw material. The effects of molecular weight of GCL3J on its adsorption behaviors and dispersion properties in coal water slurry were investigated. Rheological property investigations show that GCL3J series are better than FDN in reducing the viscosities of coal water slurry, especially for GCL3J-3 which Mw and inherent viscosity are 31 500 Da and 8.06 mL/g, respectively. Adsorption results show that all the adsorption isotherms of GCL3J on coal surface are belonging to Langmuir monolayer adsorption. With the increase of molecular weight, the adsorption amounts on coal surface decrease. Zeta potential results show that the adsorption forces between GCL3J and coal surface increase with the increase of molecular weight.