Preparation and amino modification of mesoporous carbon from bagasse via microwave activation and ethylenediamine polymerization for Pb(II) adsorption

Abstract

Bagasse mesoporous carbon (MC) was designed using an L9 (34) orthogonal experiment and then modified as a cost-effective absorbent for Pb(II) via nitric acid oxidation and ethylenediamine polymerization. X-ray photoelectron spectroscopy (XPS) and FTIR analyses indicated that amino groups were successfully introduced into the MC after modification. Pore characterization showed that the modified carbon maintained high mesoporosity. The adsorption behavior of Pb(II) and its associated factors including pH, initial concentration, adsorbent dose, temperature, and contact time were further investigated. Results proved that the modified carbon showed excellent Pb(II) adsorption performance, which could be due to the large number of mesopores and introduced amino groups. The adsorption capacity also increased with increasing solution temperature and reached the maximum adsorption amount of 185 mg g−1. The adsorption rate was primarily controlled by intra-particle diffusion, indicating that the pore size of the carbon was a significant factor. The results of XPS before and after Pb(II) adsorption revealed that the grafted amino groups enhanced the adsorption. The modified carbon was tested on real water samples and exhibited high removal capacities. These findings indicate that the bagasse MC could be a suitable precursor for the preparation of amino-rich mesoporous materials with significant Pb(II) adsorption performance.