A kinetic investigation of the flocculation of alumina with polyacrylic acid.
A kinetic investigation of the flocculation of alumina with polyacrylic acid.
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DOI：
10.1016/j.jcis.2003.11.010
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发表时间：
2004-03
影响因子：
9.9
通讯作者：
K. Das;P. Somasundaran
中科院分区：
文献类型：
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作者：
K. Das;P. Somasundaran
使用模型胶体系统的氧化铝和聚丙烯酸（PAA），絮凝的动力学进行了研究，在低聚合物浓度和短的持续时间（秒的顺序）。聚合物诱导的絮凝过程服从Von Smoluchowski双分子速率方程。聚合物浓度的增加导致絮凝过程的速率常数更高。在固定浓度下（例如50 ppb，十亿分之一），速率常数值显示250，000 gmol− 1聚丙烯酸的最大值。在此聚合物浓度下，不同分子量的PAA分子对氧化铝表面覆盖率的计算表明，在所有情况下，覆盖率几乎相同，均为10.1 ×10−3，但絮凝反应和速率明显不同。絮凝特性的这种趋势归因于有效絮凝的临界聚合物数密度要求（至少部分电荷中和和絮凝的引发）。超低浓度（50 ppb）下的絮凝机制是部分斑块中和和桥接的协同效应。
Using a model colloidal system of alumina and polyacrylic acid (PAA), the kinetics of flocculation was investigated at low polymer concentrations and short durations (on the order of seconds). The polymer-induced flocculation processes obeyed Von Smoluchowski's bimolecular rate equation. Increases in the concentration of the polymer resulted in higher rate constants for the flocculation process. At a fixed concentration (say 50 ppb, parts per billion), the rate constant values showed a maximum value for 250,000 gmol−1polyacrylic acid. At this polymer concentration, calculations of the surface coverage of alumina by PAA molecules of different molecular weights show that for all the cases the coverage is nearly the same, ∼1×10−3, but the flocculation response and the rates are significantly different. This trend in flocculation characteristics is attributed to the critical polymer number density requirement for effective flocculation (at least partial charge neutralization and initiation of flocculation). The mechanism governing the flocculation at ultralow concentrations (50 ppb) is the synergistic effect of partial patch neutralization and bridging.