Highly Cost-Effective Nitrogen-Doped Porous Coconut Shell-Based CO₂ Sorbent Synthesized by Combining Ammoxidation with KOH Activation

Abstract

The objective of this research is to develop a cost-effective carbonaceous CO2 sorbent. Highly nanoporous N-doped carbons were synthesized with coconut shell by combining ammoxidation with KOH activation. The resultant carbons have characteristics of highly developed porosities and large nitrogen loadings. The prepared carbons exhibit high CO2 adsorption capacities of 3.44-4.26 and 4.77-6.52 mmol/g at 25 and 0 °C under atmospheric pressure, respectively. Specifically, the sample NC-650-1 prepared under very mild conditions (650 °C and KOH/precursor ratio of 1) shows the CO2 uptake 4.26 mmol/g at 25 °C, which is among the best of the known nitrogen-doped porous carbons. The high CO2 capture capacity of the sorbent can be attributed to its high microporosity and nitrogen content. In addition, the CO2/N2 selectivity of the sorbent is as high as 29, higher than that of many reported CO2 sorbents. Finally, this N-doped carbon exhibits CO2 heats of adsorption as high as 42 kJ/mol. The multiple advantages of these cost-effective coconut shell-based carbons demonstrate that they are excellent candidates for CO2 capture.

Imine-Linked Polymer Based Nitrogen-Doped Porous Activated Carbon for Efficient and Selective CO2 Capture

“…As expected, at zero-loading, NAC-800 shows an heat of adsorption (Qst) of 42.6 kJ mol −1 , comparatively higher than that of NAC-600 and NAC-700 (40.1 and 37.6 kJ mol −1 ) respectively. However, the Qst values are obviously bigger than those mentioned previously for typical carbonaceous adsorbents182932. The high Qst value of NAC-800 is in consistent with the steep curve of the CO 2 .…”

Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO2 Uptake at Low Pressures

“…Moreover, MOPs with tunable chemical composition allow the avoidance of undesired complex treatment with toxic and corrosive ammonia or liquid acid to introduce basic sites 31,32 in the activation process. Hence, the development of HPCs derived from MOPs appears to be worthy of enormous efforts.…”

Porous carbons from hydrothermal carbonization of corn stover for highly efficient CO2 capture

“…A 2:1 KOH:HC ratio was found to give the highest CO 2 uptake amount for the range of KOH:HC ratios examined. Sevilla and Yang et al reported that activated carbon prepared from at a KOH: HC ratio of 2 exhibited better adsorption capacity than the other ratios [12,25]. Although AC 800-1-2 had a lower BET surface area, total pore volume and even micropore volume than AC 800-4-2 , its capacity for CO 2 adsorption was higher (Table 1), which can probably be explained by its higher N content and narrow micropore volume of less than 0.7 nm ( Table 1).…”

“…Compared with these conventional precursors, biomass is a more suitable feedstock in terms of cost, availability and its renewability [10,11].Various biomass feedstocks such as coconut shells [12], peanut shells [13], bamboo [2], and empty fruit brunch [14] have been applied as carbon precursors to produce porous carbons for CO 2 sorption, by either direct chemical activation with KOH or by physical activation with CO 2 as the activation agent. However, these methods have some disadvantages such as waste stream emission and low carbon yield.…”