Waste‐Fish‐Derived Nitrogen Self‐Doped Microporous Carbon as Effective Sorbent for CO₂ Capture

Abstract

Protein‐rich waste fish was used to produce nitrogen self‐doped microporous carbon by KOH activation and studied for CO2 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 m2 g−1) and total pore volume (1.32 cm3 g−1) were exhibited by FPDC‐1‐650 whereas FPDC‐1‐550 exhibited the highest micropore volume (0.33 cm3 g−1). The synergistic effect of microporosity and nitrogen functionality had a positive influence on CO2 uptake in the FPDC. The FPDC‐0.5‐600 shows a maximum CO2 adsorption capacity of 4.03 and 6.07 mmol g−1 at 25 and 0 oC, respectively, at 1 bar. CO2 adsorption on FPDC‐x–y shows excellent recyclability and CO2/N2 selectivity in the range of 23 to 47 at 0 oC.

The Synergistic Character of Highly N‐Doped Coconut–Shell Activated Carbon for Efficient CO2 Capture

“…The presence of a sharp peak at ∼ 1610 cm À 1 is attributed to the backbone carbon C=C bond. [22] The small peak at ∼ 1740 cm À 1 confirms the stretching of C=O bond in carboxylic acid, aldehydes, ketones, or lactones, [29] whereas the stretching modes of OÀ H bending of attached aromatic carbon and deformation in carboxylic groups were attributed from 1340 to 1420 cm À 1 range. The symmetric and asymmetric vibration modes of À CÀ H were observed at ∼ 2850 and 2920 cm À 1 , respectively, which confirms the presence of TEPA on carbon surface.…”

“…The intensity ratio (R = I D /I G ) of two first-order bands (D and G) is the deciding factor of the carbon structure. The intensity of D peak (1335 cm À 1 ) is considered as I D and intensity of G peak (1585 cm À 1 ) as I G , which represents the degree of graphitization of carbon material, [22,31] Table 3, displays the Raman shift, peak intensities, and R values of parental, acid, and TEPA-treated carbon. The R values of parental and TEPA treated activated carbons were 1.12 and 1.09, respectively, and a smaller R-value represents the degree of graphitization.…”

“…[20] The AC containing enriched nitrogen on its surface enhances their basic nature [21] and increases CO 2 adsorption capacities. [22] . [23] The acid-base properties of carbon are an essential factor that resolves the activity of carbon material.…”