Rubik’s cube-shaped Linde type A zeolite synthesized from biomass for carbon dioxide capture

Materials with tunable properties are crucial for mitigating CO2 emissions. Here, uniform and well-structured porous Rubik's cube-shaped Linde type A (LTA) zeolites are synthesized for CO2 capture, representing advancement in eco-friendly and cost-effective materials. The synthesis procedure extracts melting silicon from silicon-rich biomass ashes, followed by template-free hydrothermal synthesis. The melting approach is proposed to collect silicon for high hydroxide anion concentration and outstanding flowability, accelerating reaction kinetics and yielding alkaline silicon-containing solutions to promote crystallization of zeolites. These zeolites possess CO2 sorption capacity (2.97 mmol/g at 1 bar and 298 K) and selectivity for CO2/N2 (around 255.1), influenced by ultramicropores with heterogeneous surfaces containing metal ions. Cyclic robustness during vacuum temperature swing cycles displays a low attenuation rate (approximately 7.7% over 20 cycles). Thus, Rubik's cube-shaped LTA zeolites are a promising and cost-effective approach to addressing CO2 capture challenges by leveraging readily available biomass materials.