Immobilization of nanoscale zero-valent iron particles (nZVI) with synthesized activated carbon for the adsorption and degradation of Chloramphenicol (CAP)

摘要

Nanoscale zero-valent iron particles (nZVI) immobilized by Enterommpha prolifera based-activated carbons were applied for Chloramphenicol (CAP) treatment. The porous structure, morphology and chemical composition of as-synthesized adsorbents were detected by scanning electron microscope (SEM), transmission electron microscope (TEM), N-2 adsorption-desorption isotherms, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The kinetics models (pseudo-first-order and pseudo-second-order model) and isotherms models (Langmuir, Freundlich and Temkin model) were introduced to investigate the CAP removal mechanisms, and the degradation products were analyzed using 3D-EEM fluorescence, Ultraviolet-visible spectroscopy (UV-VIS) and mass spectrograph. The modified nZVI exhibited excellent removal capacity for CAP (54525 mg/g) because of the cooperative effects of adsorption and degradation of nZVI/AC system. Thermodynamic parameters revealed an endothermic, spontaneous and feasible process for nZVI/AC with a tendency of out-of-order. Besides, 3D-EEM fluorescence and UV-VIS analysis implied that could be thoroughly decomposed by nZVI/AC but decomposition of CAP was less efficient by the nZVI. According to the degradation products of CAP analyzed utilizing mass spectrometry, dechlorination by radicals was inferred to be the potential degradation routine of CAP by nZVI/AC. (C) 2018 Elsevier B.V. All rights reserved.