Direct Air Capture: Recyclability and Exceptional CO2 Uptake Using a Superbase
Gorji et al. https://pubs.acs.org/doi/10.1021/acs.est.5c13908
Abstract:
Direct air capture (DAC) of CO2 presents challenges owing to its low concentration and the high humidity of ambient air. In this study, efficient and reversible CO2 capture from humid air was achieved using a liquid absorbent derived from a deep eutectic solvent (DES), composed of 1,5,7-triazabicyclo [4.3.0] non-6-ene (TBN) and benzyl alcohol. Unlike conventional superbases, TBN-containing DES exhibits an exceptional absorption capacity of 0.154 gCO2/gDES (3.5 mmol/g, 1.25 mol/mol) from untreated ambient air (humidity above 90%). The DES underwent 100 absorption–desorption cycles, retaining 74% of its CO2 capture capacity after 50 cycles and 50% after 100 cycles. High stability, low toxicity, very high capture capacity, recyclability, and moisture insensitivity characterize this outstanding sorbent, making it suitable for DAC. This absorbent desorbs CO2 at just 70 °C within 30 min, effectively addressing one of the most challenging steps in DAC. According to the literature survey, this unique DES outperforms all previously reported liquid absorbents for DAC in terms of recyclability, efficiency, and practicality.
The most efficient way to capture CO2 is from the exhaust gas from a gas fired boiler. Cool to remove water vapor. If air is used, you get a mixture of CO2 and nitrogen and CO2 should be condensable as dry ice. Or burn w oxygen to get higher purity.
According to climate scenarios outlined in the latest Assessment Report from the Intergovernmental Panel on Climate Change (IPCC), the world will also need technologies capable of removing and storing hundreds of billions of tons of carbon dioxide (CO2) already in the atmosphere…
In a study published in PNAS, a team led by materials scientist Raffaele Mezzenga, a professor in ETH Zurich’s Department of Health Sciences and Technology, describes a method that uses whey and byproducts from tofu production to absorb CO2…
When exposed to air, the potassium hydroxide inside the beads reacts with CO2, producing hydrogen carbonate, a salt of carbonic acid. This reaction effectively removes carbon dioxide from the atmosphere…
He estimates that one kilogram of the protein beads could theoretically capture and isolate about 100 grams of CO2 during a single operating cycle…Laboratory tests showed that the material maintained its performance through 30 cycles of carbon capture and release, with no major loss of efficiency. Over time, the adsorption capacity would eventually decline. Mezzenga estimates that replacement might be necessary after several thousand cycles.
Potassium hydroxide and CO2 makes potassium carbonate.
Potassium hydroxide does not occur in nature. Usually energy is required to make it. Key question is what is the energy source in the whey products described. Biological? Baking?
Traditionally pioneers made soap with potassium hydroxide leached from wood ashes. Potash required by plants becomes potassium hydroxide when burned. Energy comes from the fire.
Commercially potassium hydroxide is usually made by electrolysis of potassium chloride. Chlorine is the other product. Chloe-alkali process. The energy source is electricity.
Potassium is usually mined from salt deposits. In the U.S. potassium magnesium sulfate in Carlsbad, NM or potassium chloride from Sask in Canada. Most used for fertilizer.