Production of hierarchically porous carbon from natural biomass waste for efficient organic contaminants adsorption

In view of the increasing concerns in organic contaminants, the high-efficiency adsorption materials have attracted wide attention and research. In this work, the hierarchically porous carbon (HPC) with abundant macro, meso, and micropores was well prepared from abundant straw waste by a “leavening” strategy using KHCO3 as activator for the efficient removal of typical organic contaminants from water. The larger specific surface area and porous structure significantly improve the accessible adsorption surface of HPC and facilitate the transport of target pollutant, rendering the HPC adequate in reaching the desired adsorption performance. The HPC adsorbents demonstrated a higher adsorption efficiency of 99.53% and adsorption capacity of 199.07 mg g−1 in 50 mg L−1 fluoroquinolone antibiotics within 30 min. Furthermore, the HPC also presented a desirable recycling performance during the adsorption-desorption experiments. The kinetics and isotherms of adsorption processes were fitted with pseudo-second-order and Freundlich model for the HPC, while the possible adsorption mechanisms can be explained by nanoscale sorption sites, π-π interaction and hydrogen bond formation. In general, this work provided a facile way for converting the commonly biomass waste to hierarchically porous carbon materials with high sorption ability in removing organic pollutants from the water environment.