XDLVO理论解析钙离子对腐殖酸反渗透膜污染的影响机制
首发时间:2011-10-11
摘要:以extended Derjaguin-Landau-Verwey-Overbeek(XDLVO)理论定量解析腐殖酸反渗透(reverse osmosis, RO)膜污染过程中的界面相互作用,分析三种界面相互作用力在膜污染过程中扮演的角色,重点探究不同溶液pH条件下钙离子对腐殖酸RO膜污染的影响。研究结果表明:无论钙离子是否存在,对膜污染起促进作用的范德华力在pH3时为主导作用力,而减缓膜污染的极性作用力在pH7及pH10时成为主控因素。静电力在所有测试条件下作用微弱,因此对膜污染贡献很小。钙离子主要通过改变极性作用力影响腐殖酸RO膜污染行为,且其影响随溶液pH值的降低而凸显,多数情况下钙离子会促进腐殖酸RO膜污染。界面自由能与膜污染程度相关性分析表明,XDLVO理论可以合理预测不同溶液条件下腐殖酸RO膜污染行为。
关键词: 反渗透膜 界面相互作用 腐殖酸 XDLVO理论 钙离子
For information in English, please click here
Understanding reverse osmosis membrane fouling by humic acid using XDLVO approach:Effect of calcium ions
Abstract:Interfacial interactions involved in reverse osmosis (RO) membrane fouling by humic acid were quantitatively evaluated using the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) approach. The role of each individual interfacial interaction during membrane fouling was elucidated with special emphasis devoted into the influence of Ca2+ under different solution pHs. The results showed that, regardless of the presence of Ca2+, van der waals interaction favoring fouling contributed the most to the interfacial interactions at pH3, whereas the polar interaction inhibiting fouling played a dominant role at pH7 and pH10. Electrostatic double layer interaction appeared to be the weakest in all cases, thus contributing the least to membrane fouling. It was the changing of polar interaction that gave rise to the influence of Ca2+ on membrane fouling, which turned out to be more significant at lower pH. Ca2+ would accelerate humic acid RO membrane fouling at most cases. Correlation analysis between interfacial free energy and fouling extent revealed that XDLVO approach could reasonably predict humic acid RO membrane fouling behaviors under different solution conditions.
Keywords: reverse osmosis membrane interfacial interactions humic acid XDLVO approach calcium ions
论文图表:
引用
No.****
同行评议
共计0人参与
勘误表
XDLVO理论解析钙离子对腐殖酸反渗透膜污染的影响机制
评论
全部评论0/1000