Destabilization of Titania Nanosheet Suspensions by Inorganic Salts: Hofmeister Series and Schulze-Hardy Rule.
Destabilization of Titania Nanosheet Suspensions by Inorganic Salts: Hofmeister Series and Schulze-Hardy Rule.
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DOI：
10.1021/acs.jpcb.7b04286
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发表时间：
2017-06
期刊：
影响因子：
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通讯作者：
Paul Rouster;M. Pavlović;I. Szilágyi
中科院分区：
文献类型：
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作者：
Paul Rouster;M. Pavlović;I. Szilágyi
研究了离子选择性对二氧化钛纳米片（TNS）胶体稳定性的影响。粒子的电荷随溶液pH值的变化而变化，因此可以研究单价和多价阴离子作为反离子或共离子存在于体系中时对荷电和聚集行为的影响。在无机盐存在下的聚集过程主要是由静电起源的粒子间力驱动的，然而，更复杂的离子和表面之间的化学相互作用导致额外的吸引力。阴离子的吸附显着改变了表面电荷的性质，因此，对盐诱导的聚集TNS的电阻。基于它们使分散体不稳定的能力，一价离子可以根据Hofmeister系列在酸性溶液中排序，其中它们充当抗衡离子。然而，磷酸氢根阴离子的行为是非典型的，其吸附诱导的颗粒的电荷反转。多价阴离子更有效地使带相反电荷的TNS不稳定，聚集过程遵循Schulze-Hardy规则。只有弱或可忽略不计的相互作用之间的阴离子和颗粒在碱性悬浮液中，其中TNS具有负电荷。
Ion specific effects on colloidal stability of titania nanosheets (TNS) were investigated in aqueous suspensions. The charge of the particles was varied by the pH of the solutions, therefore, the influence of mono- and multivalent anions on the charging and aggregation behavior could be studied when they were present either as counter or co-ions in the systems. The aggregation processes in the presence of inorganic salts were mainly driven by interparticle forces of electrostatic origin, however, chemical interactions between more complex ions and the surface led to additional attractive forces. The adsorption of anions significantly changed the surface charge properties and hence, the resistance of the TNS against salt-induced aggregation. On the basis of their ability in destabilization of the dispersions, the monovalent ions could be ordered according to the Hofmeister series in acidic solutions, where they act as counterions. However, the behavior of the biphosphate anion was atypical and its adsorption induced charge reversal of the particles. The multivalent anions destabilized the oppositely charged TNS more effectively and the aggregation processes followed the Schulze-Hardy rule. Only weak or negligible interactions were observed between the anions and the particles in alkaline suspensions, where the TNS possessed negative charge.