Substantial volumes of hazardous shale gas produced water (SGPW) generated in unconventional natural gas exploration. Membrane distillation (MD) is a promising approach for SGPW desalination, while membrane fouling, wetting, and permeate deterioration restrict MD application. The integration of gravity-driven membrane (GDM) with MD process was proposed to improve MD performance, and different pretreatment methods (i.e., oxidation, coagulation, and granular filtration) were systematically investigated. Results showed that pretreatment released GDM fouling and improved permeate quality by enrich certain microbes’ community (e.g., Proteobacteria and Nitrosomonadaceae), greatly ensured the efficient desalination of MD. Pretreatment greatly influences GDM fouling layer morphology, leading to different flux performance. Thick/rough/hydrophilic fouling layer formed after coagulation, and thin/loose fouling layer formed after silica sand filtration improved GDM flux by 2.92 and 1.9 times, respectively. Moreover, the beneficial utilization of adsorption-biodegradation effects significantly enhanced GDM permeate quality. 100 % of ammonia and 53.99 % of UV254 were efficiently removed after zeolite filtration-GDM and granular activated carbon filtration-GDM, respectively. Compared to the surged conductivity (41.29 μS/cm) and severe flux decline (>82 %) under water recovery rate of 75 % observed in single MD for SGPW treatment, GDM economically controlled permeate conductivity (1.39-19.9 μS/cm) and MD fouling (flux decline=8.3 %-27.5 %). Exploring the mechanisms, the GDM-MD process has similarity with Janus MD membrane in SGPW treatment, significantly reduced MD fouling and wetting.

中文翻译：

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重力驱动膜与膜蒸馏集成在一起，用于高效的页岩气采出水处理


非常规天然气勘探中产生大量有害页岩气采出水 （SGPW）。膜蒸馏 （MD） 是一种很有前途的 SGPW 海水淡化方法，而膜污染、润湿和渗透液变质限制了 MD 的应用。提出了重力驱动膜 （GDM） 与 MD 工艺的整合以提高 MD 性能，并系统研究了不同的预处理方法 （即氧化、混凝和颗粒过滤）。结果表明，预处理通过富集某些微生物群落（如变形菌门和亚硝化单胞菌科）释放了 GDM 污垢并提高了渗透质量，极大地保证了 MD 的高效脱盐。预处理会极大地影响 GDM 结垢层的形态，从而导致不同的助焊剂性能。混凝后形成的厚/粗糙/亲水污垢层和硅砂过滤后形成的薄/松散污垢层分别使 GDM 通量提高了 2.92 倍和 1.9 倍。此外，吸附-生物降解效应的有益利用显著提高了 GDM 渗透质量。沸石过滤-GDM 和颗粒活性炭过滤-GDM 分别有效去除 100% 的氨和 53.99% 的 UV254。与在SGPW处理的单个MD的75%水回收率下观察到的浪涌电导率（41.29 μS/cm）和严重的磁通量下降（>82 %）相比，GDM经济地控制了渗透电导率（1.39-19.9 μS/cm）和MD结垢（磁通量下降=8.3 %-27.5 %）。探索机制，GDM-MD 工艺与 SGPW 处理中的 Janus MD 膜相似，显着减少了 MD 结垢和润湿。