Preparation of porous activated carbon from semi-coke by high temperature activation with KOH for the high-efficiency adsorption of aqueous tetracycline

Abstract Semi-coke activated carbon (SAC) were prepared from raw semi-coke (SC) by high temperature solid-state reaction with KOH and applied as an novel adsorbent to eliminate tetracycline (TC) from solution. The characteristics of SAC were dominantly affected by the mass ratio of KOH/SC and the pyrolysis temperature. As the mass ratio of KOH/SC increases, the specific surface area of SAC increased. As the pyrolysis temperature increases, the specific surface area of SAC increased firstly and then decreased. SAC prepared at optimum conditions at the pyrolysis temperature of 1073 K and mass ratio (KOH/SC) of 3:1 was found to be the specific surface area of 1365.79 m2·g-1, the pore volume of 0.38 cm3·g-1, and the average pore size of 3.1 nm. The adsorption capacity of TC increased with the increase of specific surface area and oxygen-containing functional groups, and the equilibrium adsorption capacity for TC on SAC-3 was 302.99 mg·g-1 at 298 K. The high specific surface area, abundant surface functional groups, π–π bond and hydrophobic interaction between TC and SAC-3 contribute to good performance for TC adsorption. In addition, SAC-3 showed a good ability to resist cationic interference and good regeneration performance.