xDLVO理论解析微滤膜海藻酸钠污染中pH值影响机制  

The impact of pH on microfiltration membrane fouling by sodium alginate: mechanism analysis using xDLVO theory.

作　　者：高欣玉[1] 纵瑞强 王平[1,3] 梁爽[1] 

机构地区：[1]山东大学环境科学与工程学院,山东济南250100 [2]天茁生物科技有限公司,上海201321 [3]江苏省苏州市张家港市环境保护局,江苏苏州215600

出　　处：《中国环境科学》2014年第4期958-965,共8页China Environmental Science

基　　金：高等学校博士学科点专项科研基金资助课题(200804221035);国家自然科学基金项目(50908133);留学回国人员科研启动基金项目(教外司留[2010]1561号)

摘　　要：用extended Derjaguin-Laudau-Verwey-Overbeek（xDLVO）理论定量解析不同pH值下海藻酸钠微滤膜污染过程中的界面相互作用,评价范德华力（LW）、双电层作用力（EL）、极性力（AB）对海藻酸钠微滤膜污染的相对贡献.结果表明,在pH5-9范围内,AB相互作用能起着关键作用,决定了总界面相互作用能的性质与强度.不同pH值下海藻酸钠微滤膜污染趋势（K）为pH 5〉 pH 7〉 pH 8〉 pH 9.由于与海藻酸钠之间的界面作用为引力,疏水性膜在过滤初期膜污染更为严重；污染后期亲、疏水性膜污染行为差异不明显,因为此时海藻酸钠之间的排斥性界面作用为主导.初始、后期阶段 K 值分别与膜-海藻酸钠界面自由能、海藻酸钠-海藻酸钠界面自由能有较强的线性相关性,说明xDLVO理论可以有效预测不同pH值下海藻酸钠微滤膜污染行为.Extended Derjaguin-Landau-Verwey-Overbeek （xDLVO） theory was used to quantitatively evaluate the role of interfacial interactions, i.e. Lifshitz van der Waals （LW）, acid-base （AB） and electrostatic （EL） interactions, involved in microfiltration （MF） membrane fouling by sodium alginate （SA） at various pH. In the pH range of 5-9, the AB interaction energy played a dominant role and determined the nature and magnitude of the total interaction energy. As pH increased from 5to 9, fouling potential （K） for SA fouling of MF membrane decreased in the order of pH 5 〉 pH 7 〉 pH 8 〉 pH 9. During initial filtration stage, the hydrophobic membrane was subject to more severe fouling due to its attractive total interfacial interaction with SA. During subsequent fouling stage, no significant difference was found between fouling behaviors of hydrophobic and hydrophilic membranes because of the identical repulsive interfacial interaction between SA themselves for both membranes. Fouling potentials of initial and subsequent fouling stages correlated well with the interfacial free energies of membrane-SA and SA-SA combinations, respectively. This indicated that the xDLVO theory could effectively predict SA fouling behavior of MF membrane at different solution pH.

关 键 词：PH值 微滤膜 界面相互作用 海藻酸钠 xDLVO理论 

分 类 号：X131.2[环境科学与工程—环境科学]