Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, R.O.C.
Environ Sci Technol. 2010 Oct 15;44(20):7914-20. doi: 10.1021/es101964y.
Perfluorinated compounds (PFCs) are negatively charged and have low pK(a) values in water; therefore, a laboratory-scale electro-microfiltration (EMF) unit that applies a direct-current electrical field across its membrane can greatly enhance their removal from aqueous systems. We examined the effects of an aqueous inorganic matrix (pH: 4, 7, or 10; ionic strength: 0.4-4.8 mM; ionic composition: Na(2)SO(4), NaCl, NH(4)Cl or CaCl(2)) and an organic matrix such as dissolved organic matter (DOM) on the ability of EMF to remove perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Decreased removal of PFOX (X = A or S) was observed when the proton concentration and the ionic strength increased. When the applied electrical field strength was less than the critical electrical field strength (E(critical, HA)), PFOX removal was lower in the presence of DOM. We hypothesize that these matrices affect PFOX rejection by altering membrane zeta potential during filtration in the presence of an electrical field. In addition, EMF was found to remove three other PFCs effectively (perfluorodecanoic acid, perfluorohexane sulfonate, and perfluorohexanoic acid), and was also able to remove 70% PFOX and 80% DOC from real industrial wastewaters.
全氟化合物（PFCs）带负电荷，在水中的 pK(a) 值较低；因此，应用直流电场的实验室规模电微滤（EMF）单元可以大大提高它们从水系统中的去除率。我们研究了水无机基质（pH：4、7 或 10；离子强度：0.4-4.8 mM；离子组成：Na2SO4、NaCl、NH4Cl 或 CaCl2）和有机基质（如溶解有机物（DOM））对 EMF 去除全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS）的能力的影响。当质子浓度和离子强度增加时，观察到 PFOX（X = A 或 S）的去除率降低。当施加的电场强度小于临界电场强度（E(critical, HA)）时，在 DOM 存在下，PFOX 的去除率较低。我们假设这些基质通过在电场存在下过滤时改变膜 ζ 电位来影响 PFOX 的排斥。此外，EMF 被发现可以有效地去除另外三种 PFCs（全氟癸酸、全氟己烷磺酸和全氟己酸），并且还能够从实际工业废水中去除 70%的 PFOX 和 80%的 DOC。
