Comparisons of porous, surface chemistry and adsorption properties of carbon derived from Enteromorpha prolifera activated by H4P2O7 and KOH

• Enteromorpha prolifera-based activated carbon was activated by KOH and H4P2O7.
• The properties of carbons prepared by H4P2O7 and KOH were compared.
• The activated carbon with high surface area of 3500 m2/g was prepared by KOH.
• The prepared carbons exhibited significant adsorption capacity for GR.

Enteromorpha prolifera based-activated carbons were prepared using chemical activation by H4P2O7 (PAC) and KOH (KAC) and applied as a potential adsorbent for the adsorption of acid scarlet (GR). N2 adsorption–desorption isotherms, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Boehm titration were used to compare the porous structure, surface chemical property and adsorption behavior of carbon. KAC presented higher surface area (3500 m2/g) and larger total pore volume (2.872 cm3/g). To account for the adsorption mechanisms, the kinetic models, including pseudo-first-order model, pseudo-second-order model, intraparticle diffusion model and Boyd model were introduced. The Langmuir isotherm model was better fitted with the equilibrium data than Freundlich and Dubinin–Radushkevich models. The maximum adsorption capacities of GR onto KAC and PAC were 2500 mg/g and 454 mg/g, respectively. The physical adsorption and ion-exchange were the dominating adsorption mechanism.