Membrane distillation (MD) is an emerging technology for brine concentration, but plagued by scaling/fouling/wetting in realistic applications. There has been tremendous progress in the mitigation of scaling via chemical modification to reduce the surface energy and hydraulic operation to change flow state in feed channel. But there still lacks an undisputed cognition yet which approach outperforms the others. To address this issue, this study comprehensively investigates the impact of state-of-the-art technologies on scaling mitigation based on a surface corrugated hydrophobic PVDF membrane with high flux and potential for mass production. The technology selected include CF plasma modification, pulse flow, and negative feed pressure from both thermodynamic and hydraulic perspectives. CF plasma modification resulted in a low surface energy superhydrophobic surface, but the scaling resistance of the membranes was not significantly improved. Pulse flow effectively mitigated scaling, yet the intrusion of calcium sulfate into the membrane matrix still occurred. Negative pressure at the feed channel created a stable air layer, leading to excellent stable vapor flux and distillation conductivity. The results indicated that the hydraulic operation using negative pressure at feed was an efficient approach for scaling mitigation. This study further elucidated the mechanism underlying the scaling resistance of superhydrophobic membranes and underscored the importance of hydraulic factors in enhancing the scaling resistance in MD.

中文翻译：

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增强膜蒸馏中波纹聚偏二氟乙烯疏水膜的抗结垢性：CF4 等离子体改性、脉冲流和负压的影响


膜蒸馏（MD）是一种新兴的盐水浓缩技术，但在实际应用中受到结垢/结垢/润湿的困扰。通过化学改性来降低表面能和水力操作来改变进料通道中的流动状态，在缓解结垢方面取得了巨大进展。但目前还缺乏一个无可争议的认识，即哪种方法优于其他方法。为了解决这个问题，本研究基于具有高通量和大规模生产潜力的表面波纹疏水性 PVDF 膜，全面研究了最先进的技术对缓解结垢的影响。所选技术包括 CF 等离子体改性、脉冲流以及从热力学和水力角度考虑的负进给压力。 CF等离子体改性得到了低表面能的超疏水表面，但膜的抗结垢性能并未得到显着改善。脉冲流有效地减轻了结垢，但硫酸钙侵入膜基质的情况仍然发生。进料通道的负压形成了稳定的空气层，从而实现了优异的稳定蒸气通量和蒸馏电导率。结果表明，在进料时利用负压进行液压操作是一种有效的缓解结垢方法。这项研究进一步阐明了超疏水膜抗结垢的机制，并强调了水力因素在增强MD抗结垢能力方面的重要性。