Fig. 4: DAC tests and Joule heating regeneration.
From: Capturing carbon dioxide from air with charged-sorbents
a, Cycling capacities of DAC for ten adsorption–desorption cycles for PCS-OH from TGA measurements. Adsorption 30 °C, 60 min, 400 ppm CO2 in dry air; Desorption 130 °C, 60 min, 100% N2. The cycled capacity (difference) is shown. b, DAC measurements in a sealed box filled with air at 37% RH. The mass of PCS-OH is 120 mg. c, Schematic of Joule heating for CO2 release (scale bar, 0.5 cm, sample dimensions 2 × 1 cm). d, 13C solid-state NMR spectra of sorbents with 13CO2 gas dosing at 0.9 bar: after exposure to the air for 20 min without Joule heating (control sample, red curve) and after 20 min of Joule heating around 90 °C in air (blue curve). MAS rate of 12.5 kHz. e, Proposed mechanism for CO2 release from positively (hydroxide) charged-sorbent by means of Joule heating. Schematic adapted from ref. 33, Springer Nature America. f, DAC experiments for PCS-OH, with 20 min of Joule heating regeneration under nitrogen between cycles. PCS-OH was added into the box at a time of 25 min (dashed line) for each cycle. The mass of PCS-OH in f is 33 mg.
