Zeolite pellet fabrication for biogas purification: Characterization and CO2 adsorption performance

• Optimized zeolite pellet fabrication augments carbon dioxide adsorption performance • Optimal pellet yield of 75.97±0.70% achieved at 50 mesh, 200 ○ C, 2 hours • Maximum carbon dioxide removal of 92.5±0.75% at 140 mesh, 400 ○ C, 4-hour conditions • Crystallite size reduced from 53.31 to 37.41 nanometers post-activation • Surface area of 283.01 m 2 /g with oxygen content increase to 58.30% The escalating urgency for renewable energy solutions and sustainable waste management strategies has intensified research into biogas purification technologies, particularly addressing the critical need for efficient CO 2 removal to enhance methane concentration. This study optimized zeolite pellet fabrication and evaluated their CO 2 adsorption performance for biogas purification. Zeolite samples were systematically processed through pelletization and calcination procedures, with experimental parameters encompassing particle sizes (50-140 mesh), calcination temperatures (200-400 ○ C), and durations (2-4 hours). The pelletization process achieved optimal yield performance of 75.97±0.70% under conditions of 50 mesh particle size, 200 ○ C calcination temperature, and 2-hour duration, corresponding to maximum pellet density of 1.94±0.03 g/cm 3 . Water adsorption capacity reached its peak at 3.35±0.11% utilizing 140 mesh zeolite calcined at 400 ○ C for 4 hours. Most significantly, CO 2 removal efficiency achieved 92.5±0.75% under optimal conditions of 140 mesh particle size, 400 ○ C calcination temperature, and 4-hour calcination duration. Comprehensive characterization revealed crystallite size reduction from 53.31 nm to 37.41 nm following activation, while scanning electron microscopy confirmed heterogeneous pore structure with grain-like surface morphology. Energy dispersive X-ray spectroscopy analysis indicated substantial oxygen content increase from 31.31% to 58.30% post-CO 2 adsorption, accompanied by carbon content decrease from 30.59% to 5.54%. N 2 adsorption quantified surface area, pore volume, and pore diameter as 283.01 m 2 /g, 0.292 cc/g, and 2.569 Å, respectively. These findings establish zeolite pellets as highly effective CO 2 adsorbents with substantial potential for industrial-scale biogas purification implementation.