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The urgent need to address climate change and its environmental consequences demands innovative carbon capture technologies, given the relationship between rising global temperatures and increased atmospheric CO2levels. Here, we present a reversible photochemical carbon capture and release strategy and system utilizing photoactive pyranine in an aqueous bicarbonate buffer system. Control experiments suggested that the photoacid effect occurs at the surface which contributes to CO2release, complemented by the photothermal effect at the surface and in the bulk. A continuous flow setup employing a tube-in-tube configuration with a hollow fiber membrane demonstrates the efficiency and reliability of the visible light-driven carbon capture system, with the release of CO2captured from a 15% CO2feed in the dark, at a rate of 0.48 mmol CO2per hour to a nitrogen sweep stream under light irradiation at 200 W/m2, a level comparable to solar intensity of visible light (150 W/m2of blue light −250 W/m2of blue and green light). The robustness and scalability of the system has been demonstrated, with long-term operation over 7 days yielding 60 mmol (1.34 L CO2at STP) of cumulated CO2separation. Additionally, we explored the potential for direct air capture, yielding 3 μmol of CO2separation over 2 h of operation from a bicarbonate buffer solution saturated with ambient air (420 ppm). This work introduces the prospect of photoswing of carbon capture systems, which can avoid external energy input beyond solar irradiation, offering promising avenues for addressing the challenges associated with climate change.

The work introduces composite magnetic materials designed to capture uranium from wet-process phosphoric acid (WPA) containing 6 M H3PO4, 2% H2SO4, sodium fluoride, and metal salts of Fe(III) and Al(III). The materials include poly(vinyl chloride) (PVC) covalently modified with N,N-diethyldithiocarbamate (DEDTC) or O,O-diethyldithiophosphate (DEDTP) moieties by nucleophilic substitution of the >C–Cl bonds of PVC. To maintain the polymer processability, the maximum substitution degree was kept below 42%. The modified PVC formed stable organic gel (lyogel) materials with liquid uranium extractants such as di(2-ethylhexyl)phosphoric acid (DEHPA) or a liquid mixture of trialkylphosphine oxides, Cyanex 923. To impart the magnetic recoverability to the lyogels, iron nanoparticles (20–50 nm) coated by carbon for chemical stability were incorporated. The resulting magnetic lyogels contain variable contents of liquid extractants, maintain particle shape, exhibit very low leaching of the extractants, and are chemically stable in extremely corrosive acidic environments. Kinetics of uranium capture and equilibrium sorption capabilities of the magnetic lyogels have been evaluated. The lyogels are readily recovered by a magnet and recycled without any loss of the material. Efficient uranium stripping from the lyogels is enabled by 1 M aqueous ammonium carbonate. Lyogel recyclability and reuse were demonstrated in at least three cycles of the uranium loading and recovery.

Polymer substrates have been functionalized with a MOF material (MIL-47) synthesized directly on polyacrylonitrile using in situ microwave irradiation. The growth of MIL-47 on these substrates was studied as a function of microwave irradiation time using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The conversion of nitrile to carboxylic acid groups on the PAN surface was necessary for the growth of MIL-47 on the substrate. MIL-47 crystals grew over time at the expense of a related disordered precursor phase, which lacks the long-range order of MIL-47. This work paves the way for the development of a new class of hybrid MOF-polymer materials that will extend the applications of MOFs to fields such as membrane separations, filtration, and protective textiles.