GO-PTFE复合膜强化膜蒸馏深度处理焦化废水

为了提高膜的抗污染抗润湿性能,采用表面涂覆法将氧化石墨烯(GO)结合在聚四氟乙烯(PTFE)膜表面,制备亲水-疏水复合膜用于膜蒸馏深度处理焦化废水,并对比了改性复合膜与未改性原膜的表面特性和膜蒸馏效果,分析了GO表面改性对膜蒸馏效果的强化机制。结果表明,膜表面经过GO改性后接触角由144.2°下降至103.9°,且表面出现羟基、羧基等亲水性官能团,说明膜表面亲水改性成功。GO-PTFE复合膜相比原膜通量提高了36.6%,产水电导率保持在25μS/cm,出水的荧光峰强度明显减弱,说明GO-PTFE复合膜能有效截留焦化废水中的无机盐和有机物,相比原膜的抗污染抗润湿性能显著提高。这种强化过程主要归因于GO良好的亲水性、导热性和特有的纳米孔道对污染物的截留效应。

Advanced Treatment of Coking Wastewater by GO/PTFE Composite Membrane in Membrane Distillation

In order to improve the membrane resistance to fouling and wetting, a novel hydrophilic-hydrophobic composite membrane was fabricated by coating graphene oxide(GO) on the polytetrafluoroethylene(PTFE) substrate. The prepared membrane was used for advanced treatment of coking wastewater in membrane distillation(MD), the surface characteristics and MD performance of modified and un-modified membrane were compared, and the enhancement mechanism of GO surface modification to MD performance was analyzed. Results showed that the water contact angle of membrane decreased from 144.2° to 103.9° after GO surface modification, hydrophilic functional groups such as hydroxyl and carboxyl were detected on the surface of composite membrane, indicating hydrophilic modification of membrane surface was successful. The permeate flux of GO/PTFE composite membrane increased 36.6% compared with original membrane, the permeate conductivity maintained at 25 μS/cm, and without significant fluorescence peaks detected in the distillate.This demonstrated the GO/PTFE composite membrane could effectively reject salts and organics in coking wastewater, the membrane resistance to fouling and wetting improved significantly compared to original membrane, which might be ascribed to the presence of hydrophilic functional groups, higher thermal conductivity and nanocapillary for pollutant rejection.