Tailoring Sepiolite for Efficient CO₂ Desorption: A Sustainable Approach Utilizing Acid Activation for Amine Regeneration Optimization

Abstract

In the context of industrial CO2 capture, the need for efficient solvent regeneration at lower temperatures poses a significant challenge. Catalyst-assisted enhancement of the CO2 desorption kinetics has emerged as a potential solution. This study introduces a series of cost-effective and readily available sepiolite clay-based catalysts activated via simple acid treatments. This activation significantly enhances both the surface area and surface acidity, laying the foundation for more effective catalysts. Experimental results at a moderate temperature of 88 °C demonstrate the effectiveness of the prepared catalysts, resulting in remarkable improvements: up to a 163.6% increase in the CO2 desorption rate, an up to 83.6% increase in the desorbed CO2 quantity, and a reduction of up to 45.6% in heat duty compared with the baseline amine solution. Furthermore, the prepared catalysts exhibit facile separability through filtration and sustained stability over 10 cycles. To shed light on the underlying chemical processes, we also present a plausible reaction mechanism for the acid-activated sepiolite-catalyzed CO2 desorption reaction. This research holds promise for environmentally friendly and cost-effective amine regeneration processes in CO2 capture applications.