Effects of inorganic electrolytes on zeta potentials of ceramic microfiltration membranes
Effects of inorganic electrolytes on zeta potentials of ceramic microfiltration membranes
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DOI：
10.1016/j.seppur.2004.06.011
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发表时间：
2005-03
影响因子：
8.6
通讯作者：
Yijiang Zhao;W. Xing;N. Xu;F. Wong
中科院分区：
文献类型：
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作者：
Yijiang Zhao;W. Xing;N. Xu;F. Wong
膜材料表面电学性质的表征是理解和预测膜过滤性能的关键。本文研究了氧化铝基陶瓷微滤膜的电学性能。膜的Zeta电位是在无机盐工业中常见的各种电解液，包括氯化钠、氯化铵、氯化钙、氯化铁、三氯化铝、硫酸钠、硫酸钠、磷酸三钠、硫酸亚铁和铝(Al2(SO4)3)3存在的情况下，通过电渗透测量来测定的。当离子强度为0.01m时，Zeta电位可在较宽的pH值范围(2-12)内获得。在NaC l溶液中，Zeta电位随离子强度的增加而降低，等电点与离子强度的关系不大，表明Cl、−和Na+离子不存在特定的吸附。在FeCl2、CaCl2和AlCl3溶液中，膜的等电点向较高的pH值移动，显示出对阳离子的特定吸附，而S2−、[公式：见文本]、[公式：见文本]离子的特定吸附将等电点移动到较低的pH值。FeSO4和Al2(SO4)3溶液中的Zeta电位很低，表明阳离子和阴离子在膜表面的络合共吸附降低了膜表面的电荷密度。
The characterization of surface electrical properties of membrane materials is critical for understanding and predicting filtration performances of membranes. In this paper, electrical properties of alumina-based ceramic microfiltration membrane were studied. Zeta potential of the membranes itself is determined using electro-osmosis measurements in the presence of various electrolytes, including NaCl, NH4Cl, CaCl2, FeCl2, AlCl3, Na2SO4, Na2S, Na3PO4, FeSO4and Al2(SO4)3, which are commonly encountered in inorganic salt industry. The zeta potential is obtained over a wide range of pH values (2–12) at ionic strengths of 0.01M. The zeta potential decreases with increase of ionic strength in the NaCl solution and isoelectric point (IEP) shows little dependence on the ionic strength indicating the absence of a specific adsorption of Cl−and Na+ions. The shifting of the IEP of the membrane to a higher pH value in FeCl2, CaCl2and AlCl3solutions shows specific adsorption of the cations, and specific adsorption of the S2−, [Formula: see text] , [Formula: see text] ions shifts the IEP to a lower pH value. The zeta potential in FeSO4and Al2(SO4)3solutions were very low, indicating a decrease of charge density on the membrane surface due to the complex co-adsorption of the cations and the anions on the membrane surface.