对含铁料液的减压膜蒸馏处理

摘要

The self-made PVDF hydrophobic hollow fiber membrane module is used to treat wastewater which contains iron by vacuum membrane distillation, and the orthogonal experiments of three factors three levels are designed to study the influence of iron concentration, pH value and salt ratio on membrane distillation process. By monitoring the surface morphology, element compositions and the contact angle changes of membrane before and after the membrane distillation experiment, the membrane pollution and water-logging phenomenon in the process of membrane distillation is discussed. The experimental result shows that: The iron concentration, pH value and salt rate all have significant effects on the decline of flux, the influence of pH factor is the largest, iron concentration is the second smallest, and salt ratio the last; after the experiment, there is a fouling layer on membrane surface, new elements of Na and Fe are found, their element composition are respectively 3.6% and 7%, and the contact angle has obvious change from 82°to 72° , which shows that there is a downward trend on hydrophobic performance.%采用自制PVDF疏水性中空纤维膜组件对模拟含铁废水进行减压膜蒸馏处理,设计三因素三水平正交实验,研究料液中铁离子浓度、pH值以及含盐率对膜蒸馏过程的影响.通过监测膜蒸馏实验前后膜丝内表面形貌、元素组成及接触角变化,对膜蒸馏过程中的膜污染及膜亲水化现象进行初步探讨.实验结果表明:铁浓度、pH值及含盐率对膜通量的衰减均有显著影响,pH值影响最大,铁浓度次之,含盐率最小；膜蒸馏实验后膜丝表面有污染物聚集,XPS结果显示出现了新元素Na和Fe,其质量分数分别占到了36％和7.0％,而且膜丝内壁的接触角从实验前82°降到72°,说明疏水性能有下降趋势.