Adsorption and removal of tetracycline from water by petroleum coke-derived highly porous activated carbon

Herein, petroleum coke (PC) derived activated carbons (ACs) were prepared via KOH activation process. The as-prepared ACs exhibited a large surface area (2800-2900 m2/g) and total pore volume (1.4-2.1 cm3/g). In addition, the oxygen-correlated functional groups endow the resultant ACs with an acid surface. Combining the structural characters with the surface properties, these ACs were successfully applied for the effective removal of a commonly-used antibiotics (tetracycline) from drinking water for the first time. As a typical example, the maximum adsorption capacities of 897.6, 961.5 and 1121.5 mg/g were obtained at the temperature of 303, 313 and 323 K, respectively, for tetracycline removal, which was higher than that of other reports. Furthermore, the adsorption parameters, including the initial concentration, contact time, pH of solution, ionic strength and temperature, were investigated. The adsorption isotherms and kinetics were also discussed in detail. It was observed that the adsorption isotherms were well fitted to Freundlich model, the kinetics studies implied the adsorption process was attributed to pseudo-second-order model. The above-mentioned results proved the successful application of the as-synthesized ACs for effective removal of tetracycline.