Radiation-initiated high strength chitosan/lithium sulfonate double network hydrogel/aerogel with porosity and stability for efficient CO2 capture

Developing efficient and inexpensive CO₂ capture technologies is a significant way to reduce carbon emissions. In this work, a novel chitosan/lithium sulfonate double network high strength hydrogel is synthesized by electron beam radiation. Due to the electron beam having a wide radiation area and certain penetrating power, the free radical polymerization can be initiated more uniformly and quickly in the hydrogel. The network structure of the hydrogel prepared by radiation-initiated polymerization is more uniform than that prepared by conventional chemical initiator-initiated polymerization. Meanwhile, the introduction of the second network to construct the double network structure does not reduce the surface area of the aerogel, which is different from the conventional method of grafting or impregnation modified porous materials. Moreover, the synthesized aerogels have good physical and chemical stability. The freeze-dried aerogels possess a porous structure and CO₂ capture ability due to the CO₂-philic double network structure. Because of the inexpensive raw material and convenient radiation process, this work can reduce the cost of CO₂ adsorbents and has prospects of application in the field of CO₂ solid adsorbents.

Chitosan hydrogel is regenerated from alkali/urea aqueous solution and the lithium sulfonate second network is introduced by electron beam radiation-initiated in situ free radical polymerization. The freeze-dried aerogel has CO₂ capture capacity.