Ultrathin graphene-based membrane with precise molecular sieving and ultrafast solvent permeation

Graphene oxide (GO) membranes continue to attract intense interest due to their unique molecular sieving properties combined with fast permeation. However, their use is limited to aqueous solutions because GO membranes appear impermeable to organic solvents, a phenomenon not yet fully understood. Here, we report efficient and fast filtration of organic solutions through GO laminates containing smooth two-dimensional (2D) capillaries made from large (10-20 μm) flakes. Without modification of sieving characteristics, these membranes can be made exceptionally thin, down to â 1/410 nm, which translates into fast water and organic solvent permeation. We attribute organic solvent permeation and sieving properties to randomly distributed pinholes interconnected by short graphene channels with a width of 1 nm. With increasing membrane thickness, organic solvent permeation rates decay exponentially but water continues to permeate quickly, in agreement with previous reports. The potential of ultrathin GO laminates for organic solvent nanofiltration is demonstrated by showing >99.9% rejection of small molecular weight organic dyes dissolved in methanol. Our work significantly expands possibilities for the use of GO membranes in purification and filtration technologies

Functionalized boron nitride membranes with ultrafast solvent transport performance for molecular separation

Pressure-driven, superfast organic solvent filtration membranes have significant practical applications. An excellent filtration membrane should exhibit high selectivity and permeation in aqueous and organic solvents to meet increasing industrial demand. Here, we report an amino functionalized boron nitride (FBN) based filtration membrane with a nanochannel network for molecular separation and permeation. This membrane is highly stable in water and in several organic solvents and shows high transport performance for solvents depending on the membranes' thickness. In addition, the FBN membrane is applicable for solute screening in water as well as in organic solvents. More importantly, the FBN membranes are very stable in acidic, alkaline and oxidative media for up to one month. The fast-flow rate and good separation performance of the FBN membranes can be attributed to their stable networks of nanochannels and thin laminar structure, which provide the membranes with beneficial properties for practical separation and purification processes

Production of overhanging structures in stainless steel with selective laser melting

status: publishe

Membrane-occluded gold-palladium nanoclusters as heterogeneous catalysts for the selective oxidation of alcohols to carbonyl compounds

Pre-formed polyvinylpyrrolidone-stabilized gold-palladium clusters, consisting of 80 mol% gold and with a mean size of 1.9 nm, were immobilized quantitatively in a porous polyimide membrane via the process of phase inversion, without loss of metal nanodispersion. The obtained goldpalladium/polyimide membrane emerged as a highly active heterogeneous metal catalyst for the amide-phase and solvent-free oxidation of aliphatic, allylic and benzylic alcohols with full selectivity to the corresponding aldehydes and ketones, and could be recycled with excellently preserved catalytic activity and product selectivity. Occlusion of the optimized bimetallic clusters in the polyimide structure proved beneficial in view of their superior catalytic performance compared to the analogous colloidal gold-palladium clusters

REMOVED: Development and Optimization of Supported PTMSP-Silica Nanohybrid Pervaporation Membranes for Alcohol/Water Separations

This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)