Sustainable and hierarchical porous Enteromorpha prolifera based carbon for CO2 capture

Nitrogen-containing porous carbon was synthesized from an ocean pollutant. Enteromorpha prolifera, via hydrothermal carbonization and potassium hydroxide activation. Carbons contained as much as 2.6% nitrogen in their as-prepared state. Physical and chemical properties were characterized by XRD, N-2 sorption, FTIR, SEM, TEM, and elemental analysis. The carbon exhibited a hierarchical structure with interconnected microporosity, mesoporosity and macroporosity. Inorganic minerals in the carbon matrix contributed to the development of mesoporosity and macroporosity, functioning as an in situ hard template. The carbon manifested high CO2 capacity and facile regeneration at room temperature. The CO2 sorption performance was investigated in the range of 0-75 degrees C. The dynamic uptake of CO2 is 61.4 mg/g and 105 mg/g at 25 degrees C and 0 degrees C, respectively, using 15% CO2 (v/v) in N-2. Meanwhile, regeneration under Ar at 25 degrees C recovered 89% of the carbon's initial uptake after eight cycles. A piecewise model was employed to analyze the CO2 adsorption kinetics; the Avrami model fit well with a correlation coefficient (R-2) of 0.98 and 0.99 at 0 degrees C and 25 degrees C, respectively. (C) 2012 Elsevier B.V. All rights reserved.