Adsorption Behavior and Mechanism of Norfloxacin by Modified Zeolite

Natural zeolite (NZ) was modified by acid, alkali, salt soaking treatments and calcination. The adsorption properties of the modified zeolite were studied. Natural zeolite and hydrochloric acid modified zeolite (HAMZ) were characterized by Scanning Electron Microscope (SEM)，Brunauer-Emmett-Teller (BET) and X-ray diffraction (XRD). Comparing with the NZ, the surface area of HAMZ increased from 6.55 m2/g to 9.53 m2/g, the pore volume increased from 4.75 mm3/g to 11.49 mm3/g, large radii of cations were reduced in zeolite pores, and the adsorption activity centers were then increased. HAMZ could enhance the maximum adsorption capacity of Norfloxacin (NX) by 41.0%. The adsorption kinetic of Norfloxacin by HAMZ is followed the pseudo-second-order model, and the adsorption isotherm confirms to the Langmuir model. The thermodynamic study showed that the adsorption reaction is a spontaneous endothermic reaction and the entropy increases. The adsorption forces include electrostatic force, hydrogen bonding, electron donor and acceptor interaction and - interaction. The study provides an economical and effective method for the removal of Norfloxacin in water.