Pervaporation (PV), a membrane process in which the feed is a liquid mixture and the permeate is removed as a vapour, offers an energy-efficient alternative to conventional separation processes such as distillation, and can be applied to mixtures that are difficult to separate, such as azeotropes. Here the principles of pervaporation and its industrial applications are outlined. Two classes of material that show promise for use in PV membranes are described: Polymers of intrinsic microporosity (PIMs) and 2D materials such as graphene. The literature regarding PV utilizing the prototypical PIM (PIM-1) and it hydrophilic hydrolysed form (cPIM-1) is reviewed. Self-standing PIM-1 membranes give competitive results compared to other membranes reported in the literature for the separation of alcohols and other volatile organic compounds from aqueous solution, and for organic/organic separations such as methanol/ethylene glycol and dimethyl carbonate/methanol mixtures. Blends of cPIM-1 with conventional polymers improve the flux for dehydration of alcohols. The incorporation of fillers, such as functionalised graphene-like fillers, into PIM-1 to form mixed matrix membranes can enhance the separation performance. Thin film composite (TFC) membranes enable very high fluxes to be achieved when a suitable support with high surface porosity is utilised. When functionalised graphene-like fillers are introduced into the selective layer of a TFC membrane, the lateral size of the flakes needs to be carefully controlled. There is a wide range of PIMs and 2D materials yet to be explored for PV applications, which offer potential to create bespoke membranes for a wide variety of organic/aqueous and organic/organic separations.
Novel, flexible ACEL lamps have been developed for innovative display applications. These lamps contain a single emissive layer comprising of ACEL phosphor, a binder, ferroelectric nanoparticles and optional dye. This architecture reduces fabrication costs and enables high luminances (ca. 200 cd/m2) to be achieved at 110 V and 400 Hz.
A spirobifluorene polymer of intrinsic microporosity (PIM-SBF) and polyphenylene networks based on triphenylbenzene (TPB), hexaphenylbenzene (HPB) and octaphenylquinquephenyl (OPQ) were synthesised and characterized. Uncrosslinked membranes of PIM-SBF proved suitable for the separation of a toluene/DMSO mixture (77:23 volume ratio) by pervaporation at 65°C, giving a separation factor of 3.9 and a flux of 2.0 kg m -2 h -1 . The addition of 5 wt% HPB network enhanced the separation factor, while OPQ and TPB networks increased the flux that could be achieved.
Composite membranes were prepared for nanofiltration of aromatic solvents. Cross-linking with AlCl3 was used to improve the stability of the PIM-1 selective layer in aromatic solvents like toluene, benzene and xylene. Nanofiltration performances of obtained membranes were tested with 4 different aromatic hydrocarbons and with 3 solvents from other classes of solvents. Obtained permeability for aromatic hydrocarbons was above 8,5 kg/m2·h·bar and retention of Remazol brilliant blue R dye with molecular mass 626 was up to 96 %. It was shown that permeability results correlated with Hansen solubility parameter and distance parameter between polymer and solvent. PIM-1 has higher permeability for non-polar hydrocarbons due to higher affinity between polymer and solvent.
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