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Many hydrofluorocarbon refrigerants used in air-conditioning and refrigeration equipment are being phased out based on international restrictions to reduce global warming. Over 1 billion kilograms of hydrofluorocarbons are in use, and recycling is imperative to preventing the release of these greenhouse gases into the atmosphere. We report on composite hollow fiber membranes that can efficiently separate a mixture of difluoromethane and pentafluoroethane that is used worldwide in air conditioners. Selective hollow fiber membranes have been fabricated with a single submicrometer coating of a copolymer of 70 mol % perfluoro(butenyl vinyl ether) and 30 mol % perfluoro(2,2-dimethyl-1,3-dioxole) that separates the azeotropic mixture into a permeate stream with a difluoromethane purity of >95 mol %. Rather than incinerating these valuable materials, this technology can be used to recycle nonregulated difluoromethane for future products and recover pentafluoroethane for use as a chemical feedstock, creating a circular economy.
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http://dx.doi.org/10.1126/sciadv.adp7414 | DOI Listing |
J Am Chem Soc
September 2025
Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Incorporating atomically thin two-dimensional (2D) materials with optical fibers expands their potential for optoelectronic applications. Recent advancements in chemical vapor deposition have enabled the batch production of these hybrid fibers, paving the way for practical implementation. However, their functionality remains constrained by the integration of a single 2D material, restricting their versatile performance.
View Article and Find Full Text PDFAnalyst
September 2025
School of Information Science and Technology, Fudan University, 220 Handan Rd, Shanghai 200433, China.
Mercury(II) ions (Hg) are one of the most common and highly toxic heavy metal ions, which can contaminate the environment and damage the human health. Therefore, the precise detection of trace Hg concentration is particularly important. Herein, gold nanoparticles-enhanced silver-coated hollow fiber (HF) surface plasmon resonance (SPR) sensor was developed for the highly sensitive detection of Hg ions.
View Article and Find Full Text PDFInd Eng Chem Res
August 2025
School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Pervaporation, combined with other separation processes, can effectively remove water from fermentation product streams, making it highly suitable for purifying alcohols like 2,3-butanediol (BDO). In this study, a dense poly-(vinylidene fluoride) (PVDF) hollow fiber membrane module prototype was fabricated for BDO dehydration, achieving >0.2 LMH total flux and >95% BDO rejection.
View Article and Find Full Text PDFMaterials (Basel)
August 2025
Department of Mechanical Engineering, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, QC J1K 2R1, Canada.
This study investigates the use of a local fiber, specifically milkweed that grows in Quebec, Canada, for nonwoven building applications. Milkweed is a natural fiber with an ultra-lightweight hollow structure that provides excellent acoustic and thermal insulation properties. To provide three-dimensional stability to nonwovens, milkweed fibers were blended with a low-melt fiber composed of a polyethylene terephthalate core and a polyolefin sheath (LM 2.
View Article and Find Full Text PDFWe present an optical hydrogen sensor based on photothermal spectroscopy with a hollow-core fiber, specifically targeting the 2121.8-nm quadrupole absorption line of hydrogen. Our experiments demonstrate the sensor's capability for detecting hydrogen gas at concentrations as low as 77 ppm, with a lock-in time constant of 1 second.
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