From fish scales to highly porous N-doped carbon: a low cost material solution for CO2 capture

This article reports a strategy to use fish scales as raw materials for synthesizing CO2 capture materials. The synthesis employs thermal and chemical treatment to convert fish scales into N-rich porous carbons. The proteins in the fish scales are the major source of carbon and nitrogen. By varying the reaction conditions, the porosity and N content can be controlled in the produced porous carbons. It was found that the porosity first increases and then decreases with an increase in thermal treatment temperature; the N content decreases with an increase in the temperature. The capture capacity of the as-synthesized carbon (NFPC-750) for CO2 can be up to 171 mg g(-1) at 25 degrees C, 1 bar. This high capacity is attributable to its porous structure with a high specific surface area (up to 3206 m(2) g(-1)) and large pore volume (micropore volume up to 0.76 cm(3) g(-1) and total pore volume up to 2.29 cm(3) g(-1)). More attractively, quaternary nitrogen is effectively preserved (2.90% N), which should be another contributor to enhance the CO2 capture capacity through the chemical adsorption between nitrogen groups and CO2. In addition, the sorbent preliminarily exhibits high cycle stability with retention of 91.8% of its initial CO2 capacity after 10 cycles. This highly porous N-doped porous carbon obtained from fish scales is thus considered a promising material for CO2 capture.