Synthesis of chabazite zeolite: a dual-function material for high-performance carbon capture and para-nitrophenol removal from synthetic wastewater with comprehensive characterization and modeling

In this study, chabazite (CHA) zeolite was synthesized via an organic structure-directing agent (OSDA)-free hydrothermal method, offering a cost-effective and environmentally friendly alternative to conventional synthesis routes. The characterization confirmed its highly crystalline framework, hierarchical porosity, and thermal stability. The material was employed in a dual application for carbon capture and para-nitrophenol (PNP) removal from synthetic wastewater. CHA exhibited a high CO₂ uptake of 7.05 mmol/g at 273 K with strong selectivity over N₂, supported by an exothermic heat of adsorption (67.73 vs. 23.51 KJ/mol) and Langmuir isotherm fitting. For PNP removal, response surface methodology (RSM) optimized the process, with an R² of 0.9681. Kinetics followed a pseudo-second-order model (R² = 0.8556), and isotherm results aligned with the Freundlich model (R² = 0.9762), with a maximum adsorption capacity of 334.13 mg/g. These results demonstrate the effectiveness of OSDA-free chabazite as a sustainable adsorbent for combined CO₂ capture and wastewater treatment.