Natural cotton-derived carbon aerogel as a binder-free CO2 adsorbent: Synthesis, characterization, and net carbon balance assessment

초록

Natural cotton-derived carbon aerogels were developed as binder-free CO2 adsorbents, and their synthesis, characterization, and thermodynamics were systematically investigated. Natural cotton was activated using H3PO4 to generate effective nanoporous structures. Various H3PO4 impregnation ratios and pyrolysis temperatures were investigated to optimize the yield and textural properties of the resulting carbon aerogels. The best-performing carbon aerogel, prepared with a 1:1 mass ratio of natural cotton to H3PO4 and pyrolyzed at 900 degrees C, exhibited a high CO2 adsorption uptake of 2.72 mol/kg at 25 degrees C and 1 bar, along with excellent cyclic stability. Beyond the laboratory performance evaluation, a comprehensive life cycle assessment was performed on an industrial-scale single-column temperature swing adsorption (TSA) process. The analysis quantified the carbon footprint of both the adsorbent synthesis and process operation and further determined the net carbon removal potential of the system. The results showed that one adsorption column with the optimized carbon aerogel required approximately 14.2 kg of CO2-equivalent emissions, and each TSA cycle enabled the net removal of CO2 after accounting for energy consumption. It was calculated that similar to 4200 cycles were required to reach net-zero emissions.

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