BALANCING THE FUTURE BY CAPTURING THE PAST AND PRESENT: DESIGN AND CONSTRUCTION OF A DIRECT AIR CAPTURE SYSTEM BASED ON MEMBRANE AND ABSORPTION TECHNOLOGIES
In 2024, global surface temperatures exceeded the 1.5°C threshold relative to preindustrial levels for the first time, highlighting the urgency of achieving net-zero CO2 emissions. Direct Air Capture (DAC) has been identified as a promising Carbon Dioxide Removal (CDR) technology for climate mitigation, while also offering benefits for indoor air quality improvement. However, despite atmospheric CO2 being considered extremely elevated, DAC faces significant challenges due to the low concentration of CO2 in the air compared to other capture methods.
This doctoral research, conducted within the CaptaCO2 project, focuses on the design and construction of a compact and energy-efficient ambient CO2 capture device based on membrane contactor technology. The system employs a functionally modified polysulfone membrane that allows CO2 to pass through its pores, facilitating its absorption into a selective solution containing carbonic anhydrase, an enzyme that catalyses its conversion into bicarbonate. The resulting solid bicarbonate can be collected and reused, providing a sustainable pathway for CO2 capture and utilization.
Given the industrial framework of this research, the study prioritizes commercial viability. To achieve this, it optimizes the manufacturing and performance of the membranes and the absorbent solution, as well as validating the system’s CO2 capture efficiency. A novel approach enabling a reversible, light-driven pH change for DAC has been developed and patented.
Finally, the thesis assesses the commercial feasibility of the CaptaCO2 system through market analysis, sustainability evaluations, and regulatory considerations, ensuring its potential for real-world implementation.
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