Waste‐Fish‐Derived Nitrogen Self‐Doped Microporous Carbon as Effective Sorbent for CO 2 Capture

Protein‐rich waste fish was used to produce nitrogen self‐doped microporous carbon by KOH activation and studied for CO 2 adsorption application. The effect of a pre‐carbonization process of dried fish powder on the textural properties and yield of fish protein derived carbon ( FPDC) was also investigated. The textural properties of FPDC‐x–y were further optimized by varying KOH to Fish powder weight ratios (x) and activation temperatures (y) . Activated carbons with high specific surface area and pore volume were obtained using mild activation conditions ( x = 0.5 to 1.5, y = 550 to 650 °C). The nitrogen content (3.79 to 12.43 wt%) and carbon yield (2.3 to15 wt%) depended strongly on the KOH to Fish powder weight ratio and activation temperature. Highest surface area (2565 m 2 g −1 ) and total pore volume (1.32 cm 3 g −1 ) were exhibited by FPDC‐1‐650 whereas FPDC‐1‐550 exhibited the highest micropore volume (0.33 cm 3 g −1 ). The synergistic effect of microporosity and nitrogen functionality had a positive influence on CO 2 uptake in the FPDC . The FPDC‐0.5‐600 shows a maximum CO 2 adsorption capacity of 4.03 and 6.07 mmol g −1 at 25 and 0 o C, respectively, at 1 bar. CO 2 adsorption on FPDC‐x–y shows excellent recyclability and CO 2 /N 2 selectivity in the range of 23 to 47 at 0 o C.