Chemical and physical aspects of organic fouling of forward osmosis membranes
Chemical and physical aspects of organic fouling of forward osmosis membranes
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DOI：
10.1016/j.memsci.2008.04.036
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发表时间：
2008-07-15
影响因子：
9.5
通讯作者：
Elimelech, Menachem
中科院分区：
文献类型：
--
作者：
Mi, Baoxia;Elimelech, Menachem
随着各学科对正渗透（FO）膜过程的日益关注，对FO膜污染的系统研究提出了更高的要求。本研究探讨了各种物理和化学相互作用的作用，如分子间粘附力，钙结合，初始渗透通量，和膜取向，在有机污染的正渗透膜。以海藻酸钠、牛血清白蛋白（BSA）和奥德里奇腐殖酸（AHA）为模型有机污染物。原子力显微镜（AFM）被用来量化的污垢和清洁或污染的膜之间的分子间粘附力，以更好地了解污染机制。有机污染和分子间粘附之间的强相关性进行了观察，表明污垢-污垢相互作用起着重要的作用，在确定有机污染的速率和程度。污垢数据表明，FO污垢是由化学和流体动力学相互作用的耦合影响。钙离子结合、渗透阻力和流体动力学剪切力是膜表面污染层形成的主要因素。然而，控制膜污染的主要因素因污染物而异。随着分子间粘附力的增强，更容易获得有利于污垢沉积的流体动力学条件，从而导致滤饼形成。在形成致密的滤饼层之前，结垢速率受分子间粘附力和流体动力学条件的影响。然而，一旦形成滤饼层，所有三种结垢物具有非常相似的通量下降速率，并且流体动力学条件的进一步变化不影响结垢行为。(C)2008 Elsevier B. V.保留所有权利。
The growing attention to forward osmosis (FO) membrane processes from various disciplines raises the demand for systematic research on FO membrane fouling. This study investigates the role of various physical and chemical interactions, such as intermolecular adhesion forces, calcium binding, initial permeate flux, and membrane orientation, in organic fouling of forward osmosis membranes. Alginate, bovine serum albumin (BSA), and Aldrich humic acid (AHA) were chosen as model organic foulants. Atomic force microscopy (AFM) was used to quantify the intermolecular adhesion forces between the foulant and the clean or fouled membrane in order to better understand the fouling mechanisms. A strong correlation between organic fouling and intermolecular adhesion was observed, indicating that foulant-foulant interaction plays an important role in determining the rate and extent of organic fouling. The fouling data showed that FO fouling is governed by the coupled influence of chemical and hydrodynamic interactions. Calcium binding, permeation drag, and hydrodynamic shear force are the major factors governing the development of a fouling layer on the membrane surface. However, the dominating factors controlling membrane fouling vary from foulant to foulant. With stronger intermolecular adhesion forces, hydrodynamic conditions for favorable foulant deposition leading to cake formation are more readily attained. Before a compact cake layer is formed, the fouling rate is affected by both the intermolecular adhesion forces and hydrodynamic conditions. However, once the cake layer forms, all three foulants have very similar flux decline rates, and further changes in hydrodynamic conditions do not influence fouling behavior. (C) 2008 Elsevier B.V. All rights reserved.