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The electromagnetic and microwave absorbing properties of nickel ferrite nanocrystals were investigated for the first time. There were two frequencies corresponding to the maximum reflection loss in a wide thickness range from 3.0 to 5.0 mm, which may be bought by the nanosize effect and the good crystallization of the nanocrystals.

Fouling of ultrafiltration (UF) membranes in oil/water separation is a long‐standing issue and a major economic barrier to their use in a broad range of applications. Currently reported membranes typically show severe fouling, resulting from the strong oil adhesion on the membrane surface and/or oil penetration inside the membranes. This greatly degrades their performance and shortens service lifetime. Here, the use of graphene oxide (GO) as a novel coating material for the fabrication of fully recoverable, UF membranes with desired hierarchical surface roughness is accomplished by a facile vacuum filtration method for antifouling oil/water separation. The combination of ultrathin, “water‐locking” GO coatings with the optimized hierarchical surface roughness, provided by the inherent roughness of the porous supports and the corrugation of the GO coatings, minimizes underwater oil adhesion on the membrane surface. Cyclic membrane performance evaluation tests revealed approximately 100% membrane recovery by facile surface water flushing, establishing their excellent easy‐to‐recover capability. The novel GO functional coatings with optimized hierarchical structures may have broad applications in oil‐polluted environments.

In this study, molecular layer deposition (MLD) was used as a novel and highly controllable method to prepare TiO 2 nanofiltration membranes with approximately 1 nm pores for water purification. Number of deposition cycles and precursors (TiCl 4 and ethylene glycol) were used to control membrane quality and final pore sizes, respectively. Optimized TiO 2 nanofiltration membranes had a pure water permeability as high as ~48 L/(m 2 •h•bar). Salt and dye rejection measurements showed moderate rejection of Na 2 SO 4 (43%) and MgSO 4 (35%) and high rejection of methylene blue (~96%). In addition, natural organic matter (NOM) removal testing showed high rejection (~99%) as well as significantly improved antifouling performance and recovery capability. MLD, as a new TiO 2 nanofiltration membrane preparation technique, has great potential to realize excellent control of membrane composition, thickness, and potentially pore sizes in a scalable way.

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