Background
Carbon dioxide removal (CDR) from atmospheric air, which includes direct air capture (DAC), is essential to limit global warming to 2°C, or ideally 1.5°C. Current DAC methods based on thermal and pressure swings remain too energy intensive. Moisture-driven DAC using strong-base anion exchange resins (AER) binds CO2 from ambient air at low humidity and releases it when exposed to moisture. Increasing relative humidity from 20% to near 100% at room temperature changes the equilibrium partial pressure over the sorbent five-hundred-fold, with energy paid through water evaporation.
Traditional DAC methods require significant energy, and extracting CO2 from sorbents often involves complex processes like immersion in alkaline water or applying vacuum pressure. Additionally, direct CO2 capture for biological conversion faces challenges due to the high pH and alkalinity conditions required for certain microalgae and cyanobacteria strains, along with inefficient CO2 delivery methods.
Invention Description
Researchers at Arizona State University have developed for a novel method and system for confining powdered or particle sorbents, including anion exchange resin (AER) particles, within elongated mesh tubes. This system cycles the powdered sorbents or sorbent sheets between CO2-depleted gas streams for capturing CO2 and CO2-replete gases, liquids, or vacuum to release concentrated CO2 streams upon exposure to moisture, heat, or vacuum pressure. The resulting concentrated CO2 is suitable for conversion by biological means, reacting with alkaline minerals to form stable carbonates for sequestering the captured CO2 from the environment, or further enriching to higher CO2 partial pressures suitable for CO2 electrolysis, thermochemical synthesis, or geologic storage.
Potential Applications
- Biological conversion
- Climate mitigation
- Industrial manufacturing
- Renewable energy sector
- Agriculture & horticulture
Benefits and Advantages
- Energy efficiency
- Enhanced CO2 capture and release
- Environmental impact
- Cost-effectiveness