微絮凝-金属膜净水组合工艺中膜污染机理探析

Fouling Mechanism in Water Treated by Microcoagulation Filtration with Metallic Membranes

采用微絮凝-金属微滤膜组合工艺处理微污染水,借助X射线能谱、电镜扫描等微观表征以及动态膜污染数学模型等方法,对微絮凝-金属膜组合工艺运行方式与膜污染机理进行研究.试验结果表明组合工艺对微污染水的浑浊度、UV254以及CODMn平均去除效率分别为97.6%、80.0%和63.1%.选用0.3μm金属膜滤芯时,采用恒通量过滤模式,膜比通量随着通量的增加逐渐从44.44L·(m2·h·kPa)-1增至58.33L·(m2·h·kPa)-1;采用恒压过滤模式,膜比通量随着压力的增加逐渐从47.91L·(m2·h·kPa)-1降至17.63L·(m2·h·kPa)-1,金属膜在恒通量运行时的膜比通量高于恒压运行,说明恒通量运行时膜阻力增长较为缓慢.通过X射线能谱分析膜表面污染物中含有O、Al和Si等元素,推断膜表面主要污染物是硅酸铝盐;通过电镜扫描与动态膜污染数学模型模拟的结果表明,金属膜膜污染的主要形式为滤饼层污染.

Micro-polluted water was treated by microcoagulation filtration with metallic membranes.The operation and fouling mechanism of micro-coagulation filtration with metallic membranes were investigated by electronic differential system(EDS),scanning transmission electro(SEM)and membrane fouling model. The highest removal rates in turbidity,UV254 and CODMnwere 97.4%、80.9%and 64.6%respectively by using 0.3μm metallic film.The specific flux(S)was increased gradually from44.44 L·(m2·h·kPa)-1to 58.33 L·(m2·h·kPa)-1 with constant flux operation and S was decreased from 47.91 L·(m2·h·kPa)-1 to17.63 L·(m2·h·kPa)-1 with constant pressure operation.The result shows S of constant flux operation is higher than that of the constant pressure operation,indicating lower membrane fouling in constant flux operation.O,Al and Si increase obviously in polluted metallic membrane,suggesting that the main component of the contaminant may be aluminum silicate.The main fouling is cake layer pollution in metallic membrane by SEM and fouling model.