Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA.
Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.
J Colloid Interface Sci. 2020 May 1;567:316-327. doi: 10.1016/j.jcis.2020.02.001. Epub 2020 Feb 4.
Flocculation performance using polyelectrolytes is influenced by critical design parameters including molecular weight, amount and sign of the ionic charge, and polymer architecture. It is expected that systematic variation of these characteristics will impact not only flocculation efficiency (FE) achieved but that charge density and architecture, specifically, can alter the flocculation mechanism. Therefore, it should be possible to tune these design parameters for a desired flocculation application.
Cationic-neutral and polyampholytic copolymers, exhibiting a range of molecular weights (10-10 g/mol), varying charge levels (0-100% cationic, neutral and anionic), and random or block copolymer architecture, were applied to dilute suspensions of silica microparticles (control) and Chlorella vulgaris. FE and zeta potential values were determined over a range of flocculant doses to evaluate effectiveness and mechanism achieved.
These different classes of copolymers provide specific benefits for flocculation, with many achieving >95% flocculation. Block copolymer flocculants exhibit a proposed, dominant bridging mechanism, therefore reducing flocculant dosage required for effective flocculation when compared to analogous random copolymer flocculants. Polyampholytic copolymers applied to C. vulgaris generally exhibited a bridging mechanism and increased FE compared to equivalent cationic-neutral copolymers, indicating a benefit of the anionic component on a more, complex, diversely charged suspension.
使用聚电解质的絮凝性能受关键设计参数的影响，包括分子量、离子电荷的数量和符号以及聚合物结构。预计这些特性的系统变化不仅会影响达到的絮凝效率（FE），而且电荷密度和结构，特别是，可以改变絮凝机制。因此，应该可以针对所需的絮凝应用调整这些设计参数。
阳离子-中性和聚两性共聚物，表现出一系列分子量（10-10 g/mol），变化的电荷水平（0-100%阳离子、中性和阴离子），以及随机或嵌段共聚物结构，应用于稀释的硅胶微粒子（对照）和普通小球藻悬浮液中。在一系列絮凝剂剂量下测定 FE 和 ζ 电位值，以评估达到的有效性和机制。
这些不同类别的共聚物为絮凝提供了特定的益处，许多共聚物的絮凝效率超过 95%。嵌段共聚物絮凝剂表现出一种提议的主导桥联机制，因此与类似的随机共聚物絮凝剂相比，减少了有效絮凝所需的絮凝剂剂量。聚两性共聚物应用于普通小球藻通常表现出桥联机制和增加的 FE，与等效的阳离子-中性共聚物相比，表明在更复杂、更多样化电荷的悬浮液中阴离子成分的益处。
