Ultra-high specific surface area activated carbon from Taihu cyanobacteria via KOH activation for enhanced methylene blue adsorption

Biomass-based activated carbon (CBACs) was successfully prepared by pyrolysis-activation of Taihu cyanobacteria. When the impregnation ratio and activated temperature were 2 and 800 oC, respectively, the optimal CBACs possessed an ultra-high specific surface (2178.90 m2·g−1) and plenty of micro-and meso-pores, as well as a high pore volume (1.01 cm3·g−1). Ascribed to ultra-high surface area, π-π interaction, electrostatic interaction, as well as hydrogen bonding interactions, the CBACs displayed huge superiority in efficient dye removal. The saturated methylene blue (MB) adsorption capacity by CBACs could be as high as 1143.4 mg·g−1, superior to other reported biomass-activated carbons. The adsorption was endothermic and modelled well by the pseudo-second-order kinetic, intra-particle diffusion, and Langmuir models. This work presented the effectiveness of Taihu cyanobacteria adsorbent ascribed to its super large specific surface area and high adsorption ability.