Chemically activated high grade nanoporous carbons from low density renewable biomass (Agave sisalana) for the removal of pharmaceuticals

Hypothesis: Enlarging the range of viable nanoporous carbon precursors, namely by the acid treatment of low density biomass residues, can overcome issues related with the availability and quality of raw materials that have potential impact on cost and quality grade of the final product. Experiments: Nanoporous carbons were prepared following a two-step process: H2SO4 digestion/polycondensation of biomass waste (Agave sisalana, sisal) at temperature below 100 degrees C and atmospheric pressure to obtain acid-chars that were further chemically activated with ICON or K2CO3. Selected synthesized nanoporous carbons were tested for the removal of pharmaceutical compounds - ibuprofen and iopamidol - in aqueous solutions. Findings: The structure and density of the acid-chars are highly dependent on the concentration of H2SO4 used in the digestion and polycondensation steps. An adequate choice of the acid-char synthesis conditions, activating agent and contact method allowed to feature nanoporous carbons with specific surface areas ranging from 600 to 2300 m(2) g(-1) and apparent densities reaching 600 kg m(-3). The adsorption capacity of a sample obtained by KOH-activation for the removal of micropollutants from water was twice higher than the value attained by a golden activated carbon (Cabot-Norit) commercialized for this specific purpose. (C) 2018 Elsevier Inc. All rights reserved.