Synthesis and characterization of magnetic K2CO3-activated carbon produced from bamboo shoot for the adsorption of Rhodamine b and CO2 capture

Abstract

Activated carbon has a wide range of applications in purifying water and air, and still has a huge potential market in the field of environmental protection. In this paper, a series of bamboo shoot shell-derived porous carbons were prepared by a two-step method of carbonization and potassium carbonate (K2CO3) activation. These biomass porous carbon chars were used for CO2 adsorption from flue gas and removal of Rhodamine B (RhB) from wastewater. The evolution of the surface structure of K2CO3 activated porous carbon was investigated by Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) surface topography analysis. After activation, the specific surface area of the sample increased from 80.35 m2/g to 1439 m2/g, and the biochar activated at 800 °C had a good CO2 adsorption capacity, reaching 6.03 and 3.44 mmol/g at 0 °C and 25 °C at 1 bar, respectively. Meanwhile, the adsorbent also showed good cycle stability and selectivity to CO2 and N2. In addition to CO2 adsorption from flue gas, the adsorption properties of porous carbons for dyes in aqueous solution at room temperature were also investigated. The results showed that the bamboo shoot shell-based porous carbon could effectively remove RhB from wastewater. Furthermore, the adsorption equilibrium was tested by Langmuir and Freundlich isotherm models. The results show that the Freundlich isotherm model is in good agreement with the experimental data, and the adsorption of RhB on porous carbon follows pseudo-second-order kinetics. The adsorbent has good CO2 adsorption and RhB removal capacity. This is due to the synergistic effect of its larger specific surface area and narrower pore size.