Preparation of High Surface Area Oxidized Activated Carbon from Peanut Shell and Application for the Removal of Organic Pollutants and Heavy Metal Ions

A peanut shell-derived oxidized activated carbon (OAC) with high surface area was prepared by zinc chloride (ZnCl2) chemical activation and subsequent nitric acid oxidation. OAC was characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and N2 adsorption-desorption. The results showed that OAC had the surface area of 1807 m2 g−1, with the total pore volume of 0.725 cm3 g−1 and average pore diameter of 3.8 nm. More importantly, when OAC acted as an adsorbent, it exhibited high efficiency to remove basic blue 41 (BB-41), congo red (CR), phenol, Cr(VI), and Pb(II) from aqueous solution due to its universality in adsorption. Batch adsorption experiments were carried out to study the effect of various parameters such as pH, initial concentration, temperature, and contact time. Also, the isotherms, kinetic models, and thermodynamics of adsorption process were investigated. The equilibrium data for CR and Pb(II) were fitted to Langmuir isotherm model, while Freundlich model was suitable for the equilibrium isotherm of BB-41, phenol, and Cr(VI), respectively. As the result indicated, peanut shell was a suitable raw material to synthesize OAC which could be employed as an efficient and universal adsorbent for removing organic pollutants and heavy metal ions from wastewater.