Scalable Biomass-Derived Hydrogels for Sustainable Carbon Dioxide Capture

Carbon capture and sequestration is a promising emissions mitigation technology to counteract ongoing climate change. The century-old amine scrubbing process is industrially mature but suffers from low energy efficiency, corrosion of facilities, and inferior stability of aqueous solutions. State-of-the-art solid sorbent-based carbon capture systems present a potentially advantageous alternative. However, practical implementation remains challenging due to limited CO₂ uptake at dilute concentrations and difficulty in regeneration of the sorbents. Here, we develop sustainable carbon-capture hydrogels (SCCH) with excellent CO₂ uptake (400 ppm) at room temperature. The rationally designed biomass gel network consists of glucomannan and cellulose, facilitating hierarchically porous structures for active CO₂ transport and capture. Pre-captured moisture significantly enhances CO₂ binding by forming water molecule-stabilized zwitterions to improve the amine utilization efficiency. In addition, the SCCH exhibits a notable advantage of low regeneration temperature at 60 °C. With rapid sorption-desorption kinetics, SCCH is capable of operating multiple cycles per day with, e.g., solar-powered regeneration. Prepared via a simple and scalable casting method with environmentally viable raw materials, SCCH highlights the potential for sustainable carbon capture from a wide range of point sources to meet global decarbonization targets.