Hierarchical Porous Carbon Derived from Carex Meyeriana Kunth with Natural Channel Arrays for Rapid and Efficient Removal of Dye and Antibiotic from Water

Abstract

The utilization of biomasses with unique natural structures as precursors may be considered as an effective strategy for the preparation of hierarchical porous carbon materials for use as adsorbents. Here, carex meyeriana Kunth (CM), a perennial herb plant with natural channel arrays, was used as the precursor for a hierarchical porous carbon material (PCCM). NaOH was used for removing SiO 2 from the surface of biochar and creating micro- and mesopores. Compared to previously-reported preparation methods for CM-derived porous carbons, the current activation process was performed at a lower temperature (800 °C rather than 1000 °C), used a shortened heating time at high temperature (from 1–2 h to 30 min), and did not require the use of hydrofluoric acid. PCCM exhibited the highest Brunauer Emmer Teller (BET) specific surface area (2700.24 m 2 g -1 ) among the CM-derived porous carbons, and its adsorbent properties were evaluated through removing chloramphenicol (CAP) and rhodamine B (RhB) from water. The Sips isothermal and Bangham kinetic models were found to fit the experimental data well, and the maximum adsorption capacities of PCCM toward CAP and RhB were 1659.43 and 1167.94 mg g -1 , respectively. The adsorption mechanism was investigated with the help of theoretical calculations. Additionally, fixed-bed column experiments were carried out to test the performance of PCCM towards the removal of RhB from water. PCCM performed better than the carbon material with much higher BET specific surface area, which may be due to its open vessel channels and abundant micro- and mesopores.

Keywords: carex meyeriana Kunth, porous carbon, adsorption, dye, antibiotic