Optimization preparation of activated carbon from Enteromorpha prolifra using response surface methodology and its adsorption studies of fluoroquinolone antibiotics

Enteromorpha prolifera, a marine solid waste abundantly available in Asia, was used as a low-cost precursor to prepare activated carbon (EPAC) using pyrophosphoric acid, H4P2O7, as a chemical activating agent. The effects of impregnation ratio, activation temperature and activation time on the specific surface area of the activated carbon were investigated through response surface methodology. The optimum preparation conditions were described as follows: impregnation ratio, 1.26; activation temperature, 455 degrees C; activation time, 48min. The characteristics of EPAC were examined by nitrogen adsorption-desorption isotherms, Fourier transformed infrared spectroscopy and scanning electron microscopy. The total pore volume and specific surface area of EPAC under optimum conditions were identified as 1.365cm(3)/g and 1124.1m(2)/g. The EPAC possessed high BJH pore volume, 1.276cm(3)/g and methylene blue value, 330mg/g, indicating the existence of abundant mesopores. The adsorption kinetic data of ciprofloxacin were well fitted to pseudo-second-order model, displaying a monolayer adsorption capacity for CIP of 216.55mg/g. The equilibrium data can be well described by Langmuir model. The dominant sorption mechanism is electrostatic attraction.