Wind-based 'rock candy' process offers simpler route to carbon capture

A research team at the University of Toronto has developed a novel carbon capture method called evaporative carbonate crystallization, which promises to reduce the capital costs of capturing CO2 from the air by up to 40%. This passive system uses long polypropylene fibers dipped in potassium hydroxide solution; capillary action draws the liquid upward, and wind-driven evaporation concentrates the solution, accelerating its reaction with atmospheric CO2. The resulting potassium carbonate forms solid crystals on the fibers, resembling “rock candy,” which can be easily washed off, bypassing the complex and costly chemical separation steps typical of existing carbon capture technologies. The captured solid potassium carbonate is then subjected to an electrochemical process that regenerates the potassium hydroxide solution and releases pure CO2 gas ready for storage or conversion into valuable chemicals like methanol and ethanol. While operating costs remain comparable to current methods, the elimination of large air contactors and chemical regeneration plants significantly lowers upfront expenses. Challenges remain, particularly regarding the system’s lower efficiency in humid conditions and the