Cationic flocculants carrying hydrophobic functionalities: applications for solid/liquid separation.
Cationic flocculants carrying hydrophobic functionalities: applications for solid/liquid separation.
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DOI：
10.1021/jp070358i
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发表时间：
2007-07
期刊：
影响因子：
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通讯作者：
S. Schwarz;W. Jaeger;B. Paulke;S. Bratskaya;N. Smolka;J. Bohrisch
中科院分区：
文献类型：
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作者：
S. Schwarz;W. Jaeger;B. Paulke;S. Bratskaya;N. Smolka;J. Bohrisch
研究了主链上带有疏水取代基的3种窄分子量分布聚阳离子[聚（N-乙烯基苄基-N，N，N-三甲基氯化铵）、聚（N-乙烯基苄基-N，N-二甲基-N-丁基氯化铵）和聚（N-乙烯基苄基吡啶氯化物）]在单分散聚苯乙烯胶乳和高岭土中的絮凝行为。显然，聚阳离子的电荷密度随着取代基疏水性的增加和聚电解质分子量的增加而降低。在具有高基底表面电荷密度的分散体中进行相分离所需的絮凝剂的量随着絮凝剂的疏水性的增加而增加。然而，疏水官能团的引入是有益的，导致有效絮凝所需的絮凝剂的最小量和最大量之间的范围（絮凝窗口）显著加宽。离子强度的增加支持这种效应。当基质具有低电荷密度时，疏水相互作用在絮凝过程中发挥更重要的作用。在这里，最低有效剂量保持相同的所有三种聚电解质的调查，但絮凝窗口的宽度增加的聚阳离子的疏水性和分子量的增加。絮凝剂的必要量随着在分散体的恒定固体含量下的颗粒尺寸的增加而增加，以及随着在恒定颗粒尺寸下的颗粒数量的减少而增加。
The flocculation behaviors of three series of polycations with narrow molecular weight distributions carrying hydrophobic substituents on their backbones [poly(N-vinylbenzyl-N,N,N-trimethylammonium chloride), poly(N-vinylbenzyl-N,N-dimethyl-N-butylammonium chloride), and poly(N-vinylbenzylpyridinium chloride)] were investigated in dispersions of monodisperse polystyrene latexes and kaolin. Apparently, the charge density of the polycations decreases with increasing substituent hydrophobicity and increasing molecular weight of the polyelectrolytes. The necessary amount of flocculant for phase separation in dispersions with high substrate surface charge densities increases with increasing hydrophobicity of the polyelectrolyte. Nevertheless, the introduction of hydrophobic functionalities is beneficial, resulting in a substantial broadening of the range between the minimum and maximum amounts of flocculant necessary for efficient flocculation (flocculation window). An increase in ionic strength supports this effect. When the substrate has a low charge density, the hydrophobic interactions play a much more significant role in the flocculation process. Here, the minimum efficient doses remained the same for all three polyelectrolytes investigated, but the width of the flocculation window increased as the polycation hydrophobicity and the molecular weight increased. The necessary amount of flocculant increased with an increase in particle size at constant solid content of the dispersion, as well as with a decreasing number of particles at a constant particle size.