A Novel Process for the Preparation of Binder-Free Zeolite Beads (Lta-5a) via Photopolymerization Applied in Co₂ Adsorption Field

The increasing CO2 concentration in the atmosphere has a severe influence on both the environment and human health, resulting in global warming. According to the high adsorption capacity for CO2 removal, zeolites play an important role for CO2 capture and sequestration. However, its powdery form limits their use in adsorption applications. When binding agents are used, the zeolite porosity is partially occluded that compromises the CO2 adsorption capacity severely. How to prepare binder-free zeolite beads with a certain structure strength and how to keep the high surface area and porosity are a great challenge. In this work, LTA-5A beads composites (80 wt.%) are prepared via cationic photopolymerization and then calcination is performed to remove organic part to obtain LTA-5A beads with different sizes (<1.0 mm, 1.0-2.0 mm, and 2.0-3.0 mm). These beads (0.1 g) are characterized by good mechanical strength without any binder (partial bead fragmentation under 200 g-load) with a preserved zeolite porosity. This method allows to exploit the zeolite beads reaching a high specific surface area (586 688 m(2) g(-1)) and good CO2 adsorption capacity (4.5-4.9 mmol g(-1)). These values are higher than those of commercial LTA-5A beads (515 m(2) g(-1) and 3.8 mmol g(-1), respectively), which is in agreement with their binder-free structure.