Corn husk derived magnetized activated carbon for the removal of phenol and para-nitrophenol from aqueous solution: Interaction mechanism, insights on adsorbent characteristics, and isothermal, kinetic and thermodynamic properties.

In this study, waste corn husk was used for the synthesis of an effective adsorbent (cornhusk activated carbon, CHAC) and by treating at two different temperatures, 250 °C (CHAC-250) and 500 °C (CHAC-500) to check adsorption efficiency. The synthesized adsorbents were characterized with the help of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy, Particle size analysis and x-ray diffraction (XRD), which revealed the different properties of the two adsorbents. The synthesized adsorbents were applied for the removal of phenol and p-nitrophenol (PNP) from aqueous solution. CHAC-500 was more efficient than the CHAC-250. The maximum adsorptions of phenol and PNP by CHAC-500 were ∼96% and ∼94%, respectively, while the maximum adsorptions of phenol and PNP by CHAC-250 were ∼81% and ∼84%, respectively. The adsorption processes were best fitted with the Langmuir adsorption isotherm and the pseudo-second-order kinetic model. The adsorption of phenol was an exothermic process, while that of PNP was an endothermic process, on both adsorbents.