3D Hierarchical Porous Activated Carbon Derived from Bamboo and Its Application for Textile Dye Removal: Kinetics, Isotherms, and Thermodynamic Studies

In this study, activated carbons were prepared from bamboo via carbonization and successive KOH activation by tuning the post-treatment procedure. The resultant carbons possessed high surface area, high oxygen doping, and 3D hierarchical porous structure with interconnected micro-, meso- and macropores. These features resulted in ultra-excellent adsorption capacity for rhodamine B (> 1200 mg/g). Furthermore, the kinetic and isotherm experimental data were best described by pseudo-second kinetic model and Langmuir isotherm model, respectively. The adsorption of RhB onto the as-synthesized carbons was a spontaneous endothermic process. The π–π stacking, hydrogen bond, and acid-base interaction were proposed to account for the adsorption mechanism. Moreover, SiO2 in bamboo-based carbon functioned as frameworks and its removal via alkali treatment led to the collapse of porous structure, decreasing surface area, pore volume, and O heteroatom doping, consequently dropping the adsorption performance. Overall, bamboo as an abundant and renewable biomass could be considered as a potential precursor for the production of excellent adsorbent for wastewater purification.