Carbon dioxide capture from flue gas using tri-sodium phosphate as an effective sorbent

Fossil fuels are dominant as an energy source, typically producing carbon dioxide (CO₂) and enhancing global climate change. The present work reports the application of low-cost tri-sodium phosphate (TSP) to capture CO₂ from model flue gas (CO₂ + N₂) mixture, in a batch mode and fixed-bed setup. It is observed that TSP has a high CO₂ capture capacity as well as high CO₂ selectivity. At ambient temperature, TSP shows a maximum CO₂ capture capacity of 198 mg CO₂/g of TSP. Furthermore, the CO₂ capture efficiency of TSP over a flue gas mixture was found to be more than 90%. Fresh and spent materials were characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and Fourier transformed infrared spectroscopy (FTIR). Preliminary experiments were also conducted to evaluate the performance of regenerated TSP. The spent TSP was regenerated using sodium hydroxide (NaOH) and its recyclability was tested for three consecutive cycles. A conceptual prototype for post-combustion CO₂ capture based on TSP material has also been discussed.