Sorption of norfloxacin from aqueous solutions by activated carbon developed from Trapa natans husk

The low-cost activated carbon was prepared from a renewable aquatic plant residue, Trapa natans husk, and tested for its ability to remove norfloxacin (NOR) from aqueous solutions. Physical and chemical properties of the Trapa natans husk activated carbon (TAC) were characterized. TAC has a large surface area of 1274 m(2)/g and mesoporous structure. Carboxylic and hydroxyl groups contributed to the sorption of NOR onto TAC but they were not the most important factors in the sorption process. The rates of adsorption followed the pseudo-second-order kinetics and the overall rate of NOR uptake was controlled by both external mass transfer and intro particle diffusion during the entire adsorption period. The equilibrium data fitted well with the Freundlich and Tempkin models and the sorption was found to be a favorable process. The adsorption of NOR by TAC was strongly dependent on the solution pH. Electrostatic interaction and hydrophobic interaction were proposed to be the principal NOR sorption mechanism.