Preparation of activated carbon from peanut shell with KOH activation and its application for H₂S adsorption in confined space

Hydrogen sulfide (H₂S), as a major air pollutant, poses a serious threat to people's health, especially in confined spaces. In this study, a porous carbon filter was developed by impregnating a copper on activated carbon derived from peanut shell biomass. The carbonization temperature can significantly affect the texture properties of activated carbon, and the optimized temperature was 450 °C. The optimal activated carbon sample (S_BET = 1523.2 m²/g, V_micro = 0.533 cm³/g) was prepared at a carbonization temperature of 450℃and KOH activation at 750 °C. The best adsorption performance was obtained with a copper impregnated optimal activated carbon (Cu/PAC-450) filter, and the maximum adsorption capacity was found to be 97.63 mg/g. As the initial concentration of H₂S increased, the adsorption efficiency decreased. Adsorption isotherm and kinetic studies showed that Langmuir isotherm model was the best-fitted model for the adsorption of H₂S on Cu/PAC-450 filter, with a correlation coefficient of 0.9627. The adsorption kinetic process followed the pseudo first order model, and the adsorption mechanism was controlled by intraparticle diffusion along with film diffusion model. The used Cu/PAC-450 filter can be successfully regenerated, which showed good reusability. The Cu/PAC-450 has a very broad prospect for use in household appliances (such as refrigerator, air conditioner, microwave oven, etc.) for indoor air purification. Therefore, this study is expected to expand the utilization of agriculture waste for the indoor air purification.