Statistical modeling of methylene blue dye adsorption by high surface area mesoporous activated carbon from bamboo chip using KOH-assisted thermal activation

Abstract

Bamboo chip (BC) biomass was used as an alternative precursor for producing high surface area and mesoporous bamboo chip activated carbon using KOH activation with pyrolysis process. Various characterization methods were employed to study the morphological characteristics, material crystallinity, surface area property, elemental composition, and surface functional group of the bamboo chip activated carbon (BCAC). The Brunauer–Emmett–Teller analysis showed that the bamboo chip activated carbon has a high surface area (720.69 m2/g) and mesoporous structure (mean pore diameter 7.32 nm). The adsorption property of bamboo chip activated carbon for the removal of methylene blue (MB) from aqueous media was evaluated. The effect of key adsorption parameters such as the bamboo chip activated carbon dose (A: 0.02–0.1 g/L), pH (B: 3–10), temperature (C: 30–50 °C), and time (D: 5–20 min) was optimized using a response surface methodology–Box–Behnken design. The kinetics of adsorption obeyed a pseudo-first order. The adsorption equilibrium was well described by the Freundlich isotherm model. The maximum adsorption capacity (qm) of MB dye was found to be 305.3 mg/g at 40 °C. The MB dye adsorption mechanism onto bamboo chip activated carbon surface indicates various dye–adsorbent interactions: electrostatic attraction, π–π interaction, and H-bonding. This study demonstrates the utility of bamboo chip as a biomass precursor for the efficient synthesis of activated carbon with favorable cationic dye adsorption properties.