1-Adamantanamine implementation in surface engineering of biomimetic PVDF-based membranes for enhanced membrane distillation

Abstract: Membrane distillation (MD) stands at the forefront of desalination technology, harnessing the power of phase change to separate water vapor from saline using minimal energy resources efficiently. In response to this challenge, membranes with tuned pores morphology and surface chemistry with biomimetic 3D pine-like structures with improved affinity to water (desalination) and/or hazardous VOC (VOC removal) were developed and studied systematically. By implementing VIPS-PVDF membranes and a green modifier of 1-adamantanamine for the first time, membranes with a revolutionary network architecture were generated. The modifier was introduced either physically to the polymeric matrix or chemically through covalent attachment onto the surface and inside the porous structure. As a result, membranes that defy wetting under extreme hydrostatic pressures (>11.5 bar) were produced while preserving unparalleled vapor transport efficiency. The 1-adamantanamine promotes transport and enhances the affinity to the VOC, ensuring excellent membrane performance at different applications of the MD process. Transport was enhanced more than 3.6 times and separation factor beta changed from 3.48 to 15.22 for MTBE removal and from 2.0 to 3.46 for EtOH removal when comparing pristine PVDF with membrane chemically modified with 1-adamantanamine (PVDF_Ch02). The process separation index during the MTBE removal changed from 20 kg m-2 h-1 (PVDF) to 297 kg m-2 h-1 (PVDF_Ch02). All materials were highly stable and durable during the MD applications. This innovative approach not only revolutionizes desalination but also holds immense promise for diverse applications beyond, particularly in the realm of wastewater treatment. A study of the icing process on a cold plate with new membranes provided deeper insight into the icing mechanism and the role of membrane LEP in it.