Nanocomposites of zero-valent Iron@Activated carbon derived from corn stalk for adsorptive removal of tetracycline antibiotics

The hybrid nanocomposites of zero-valent iron loaded the activated carbon derived from the corn stalk (ZVI@ACCS) was prepared and used to remove the antibiotics of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) from aqueous solution. The adsorption amounts of three antibiotics (103.1 mg g-1 for CTC, 72.9 mg g-1 for OTC and 81.5 mg g-1 for TC) were sensitive to the temperature and independent of pH in the range of 4.2-7.1 at 298 K through the synergistic interactions of the electrostatic attraction, the bridging complexation and the surface complexation. The equilibrium was performed within 20 min at 298 K. The spontaneous (ΔGo<0) and endothermic (ΔHo>0) adsorption of three antibiotics onto the ZVI@ACCS nanocomposites gave a better matching (r2 > 0.99) with Langmuir and pseudo-second-order models.