Production and characterization of activated carbons from asphaltene by carbon dioxide and steam for ibuprofen adsorption

This study explores the utilization of asphaltene an undesirable and abundant waste from an Algerian crude oil well, for activated carbon production via physical activation methods using two distinct activating agents: carbon dioxide and steam, at 780 °C, with varying degrees of burn-off. The carbons produced at different burn-off levels were characterized based on their nitrogen and carbon dioxide adsorption isotherms at 77 K and 273 K. The results indicate that the choice of gasification agent significantly influences the development of activated carbon porosity. Specifically, steam demonstrates higher reactivity and generally yields activated carbons with superior nitrogen adsorption capacity. Carbon dioxide activation, on the other hand, generates narrow micropores that contribute to total microporosity, while steam activation tends to widen micropores. The adsorption capacity of the resulting activated carbons (CAs) was assessed using ibuprofen as the adsorbate. Kinetic and equilibrium adsorption data indicate satisfactory removal of this contaminant. The adsorption process conforms to the pseudo-second order kinetic equation and the Sips and Langmuir adsorption models, highlighting the efficiency and reliability of the adsorption process.