Removal of methyl orange dye by high surface area biomass activated carbon prepared from bamboo fibers

To obtain a green biomass-activated carbon with abundant pores for the high-efficiency removal of dye, this study fabricated bamboo fiber-based activated carbons (BFACs) via a one-step activation strategy with the assistance of ZnCl2 as the activator for the removal of methyl orange (MO). The results showed that the specific surface area (SSA) of BFAC-500 activated at 500 degree celsius was as high as 2512 m(2)/g with a total pore volume (V-total) of 1.411 cm(3)/g. The adsorption kinetics and thermodynamics of MO conformed to the pseudo-second-order kinetic model and Langmuir isotherm model, respectively. Based on the Langmuir fitting results, the theoretical maximum adsorption capacity (Q(m)) of MO adsorbed by BFAC-500 was calculated to be 591.71 mg/g at 318 K, pH=4.5, 0.4 g/L, with an equilibrium time of about 60 min. According to the thermodynamic calculation, the value of Delta H-0 was less than 40 kJ/mol, which indicates that the adsorption mechanism was mainly based on physical adsorption, and based on the BET, Zeta potential, FTIR, and XPS before and after the adsorption, it was further known that it was mainly characterized by pore filling, electrostatic adsorption, hydrogen bonding, and pi-pi interactions. Moreover, when pH < pH(zpc), the surface of BFAC-500 was positively charged and the adsorption of Cl-, SO42- and PO43- on MO had little effect; when pH>pH(zpc), the surface was negatively charged and the adsorption of BFAC-500 on MO was enhanced by Na+, K+, and Mg2+. The BFAC materials in this study have promising applications in the practical removal of MO dyes.