Water Transport with Ultralow Friction through Partially Exfoliated g‐C3N4 Nanosheet Membranes with Self‐Supporting Spacers

Two‐dimensional (2D) graphitic carbon nitride (g‐C₃N₄) nanosheets show brilliant application potential in numerous fields. Herein, a membrane with artificial nanopores and self‐supporting spacers was fabricated by assembly of 2D g‐C₃N₄ nanosheets in a stack with elaborate structures. In water purification the g‐C₃N₄ membrane shows a better separation performance than commercial membranes. The g‐C₃N₄ membrane has a water permeance of 29 L m⁻² h⁻¹ bar⁻¹ and a rejection rate of 87 % for 3 nm molecules with a membrane thickness of 160 nm. The artificial nanopores in the g‐C₃N₄ nanosheets and the spacers between the partially exfoliated g‐C₃N₄ nanosheets provide nanochannels for water transport while bigger molecules are retained. The self‐supported nanochannels in the g‐C₃N₄ membrane are very stable and rigid enough to resist environmental challenges, such as changes to pH and pressure conditions. Permeation experiments and molecular dynamics simulations indicate that a novel nanofluidics phenomenon takes place, whereby water transport through the g‐C₃N₄ nanosheet membrane occurs with ultralow friction. The findings provide new understanding of fluidics in nanochannels and illuminate a fabrication method by which rigid nanochannels may be obtained for applications in complex or harsh environments.     

Large‐Area,Freestanding MOF Films of Planar,Curvilinear, or Micropatterned Topographies

Freestanding MOF films up to six‐inches across and replicating various surface (micro)patterns are prepared via a templated growth method. When grown on copper supports, these films have preferred orientation of the constituent crystallites, translating into markedly different wetting properties of the film's two surfaces (water‐pinning vs. water repellant). In addition, the films exhibit differential sorption of various organic solvents, can recover oil spills from seawater, and can also act as active layers of chemical sensors.     

Bestimmung des Harnstoffgehaltes von Schwimmbadw?ssern

Ohne Zusammenfassung

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Determination of the urea content of the water of swimming pools

     

Sorting of C4 Olefins with Interpenetrated Hybrid Ultramicroporous Materials by Combining Molecular Recognition and Size‐Sieving

C₄ olefin separations present one of the great challenges in hydrocarbon purifications owing to their similar structures, thus a single separation mechanism often met with limited success. Herein we report a series of anion‐pillared interpenetrated copper coordination for which the cavity and functional site disposition can be varied in 0.2 Å scale increments by altering the anion pillars and organic linkers (GeFSIX‐2‐Cu‐i (ZU‐32), NbFSIX‐2‐Cu‐i (ZU‐52), GeFSIX‐14‐Cu‐i (ZU‐33)), which enable selective recognition of different C₄ olefins. In these materials the rotation of the organic linkers is controlled to create a contracted flexible pore window that enables the size‐exclusion of specific C₄ olefins, while still adsorbing significant amounts of 1,3‐butadiene (C₄H₆) or 1‐butene (n‐C₄H₈). Combining the molecular recognition and size‐sieving effect, these materials unexpectedly realized the sieving of C₄H₆/n‐C₄H₈, C₄H₆/iso‐C₄H₈, and n‐C₄H₈/iso‐C₄H₈ with high capacity.