超疏水疏油改性PVDF膜用于膜蒸馏深度处理焦化废水

Modification of PVDF Membrane with Superhydrophobic and Oleophobic Properties for Advanced Treatment of Coking Wastewater by Membrane Distillation

采用纳米SiO_2粒子协同全氟硅烷(17-FAS)对PVDF平板膜进行表面改性,通过接触角仪、扫描电镜、X射线能谱及傅里叶变换红外光谱进行表征,并采用该材料用于膜蒸馏深度处理焦化废水。结果表明,改性后水和乙二醇的接触角分别为154.8°和137.0°,膜材料表现出了超疏水和疏油性;膜表面形成多级粗糙度结构且表面官能团发生变化,证明成功制备出SiO_2/17-FAS/PVDF复合膜材料。复合膜膜通量稳定,明显改善了原膜膜通量衰减(下降约41%)。复合膜出水中总有机碳的质量浓度从未改性前(10.0±1.3)mg/L降低至(2.0±0.3)mg/L,且色度、浊度、NH4+-N含量、UV254各指标均优于原膜出水水质。实验表明,该复合膜具有良好的抗污染性能,对膜蒸馏处理焦化废水有一定的应用潜力。

SiO2 nano-particles and perfluorodecyltriethoxy-silane（17-FAS） were used to modified the PVDF membrane, prepared membrane was characterized by contact angle instrument, scanning electron microscopy, X-ray energy spectrum and Fourier transform infrared spectroscopy, and used for advanced treatment of coking wastewater by membrane distillation. The results showed that, the contact angles of water and ethylene glycol of the modified membrane were 154.8° and 137.0°, respectively, and the membrane had good superhydrophobicity and oleophobicity. The membrane surface had multi-scale roughness and great alteration of chemical functional groups which proved SiO2/17-FAS/PVDF composite membrane was successfully prepared. The composite membrane demonstrated a stable membrane flux, which obviously improved the attenuation of raw membrane flux（decline for about 41%）. The mass concentration of TOC in the effluent of the composite membrane was reduced from（10.0±1.3） mg/L（unmodification） to（2.0±0.3）mg/L, and other parameters such as color, turbidity, NH4~＋-N content and UV254 were also improved notably. The modified PVDF membrane had a good anti-fouling performance and could be used in membrane distillation of coking wastewater.