Production and characterization of microporous activated carbon from cherry laurel (Prunus laurocrasus L.) stone: application of H2 and CH4 adsorption

Abstract

In this study, a series of activated carbons with high surface area and micropore volume were obtained by KOH activation of cherry laurel (Prunus laurocrasus L.) stone in several temperatures (500–850 °C). The physical properties of the obtained activated carbons were characterized by SEM, XRD, N2 (77 K), and CO2 (273 K). The relation between CH4 (298 K) and H2 (77 K) adsorption capacities of activated carbons in low pressures with surface area and micropore volumes was determined. Based on the results, it was found that all the activated carbons match the type I (Langmuir) isotherm; in other words, they show a characterization of micropore. The maximum BET surface area was found out as 1928 m2/g in the sample of AC850. The maximum adsorption capacity of H2 (77 K) and CH4 (298 K) in low pressure (1 atm) was found out in the sample of AC800 with 2.90 wt% and 1.47 mmol/g, respectively. It was determined that narrow micropore has a significant contribution to CH4 and H2 adsorption in low pressures, while BET surface area and total pore volume do not have a direct relation with adsorption. However, it was identified that the pores between 5 and 7 A have a significant contribution to CH4 adsorption of activated carbons, while the pores between 5 and 10 A have a similar effect on H2 adsorption.