期刊
CHEMOSPHERE
卷 161, 期 -, 页码 400-411出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.chemosphere.2016.07.025
关键词
Single-component system; Bi-component system; MIEX resin; Adsorption; Clofibric acid; Diclofenac
资金
- National Natural Science Foundation of China [51178321]
- National Major Project of Science & Technology Ministry of China [2008ZX07421-002, 2012ZX07403-001, 2012ZX07403-002]
- specialized Research Fund for the Doctoral Program of Higher Education [20120072110050]
This study demonstrates the use of MIEX resin as an efficient adsorbent for the removal of clofibric acid (CA) and diclofenac (DCF). The adsorption performance of CA and DCF are investigated by a batch mode in single-component or bi-component adsorption system. Various factors influencing the adsorption of CA and DCF, including initial concentration, contact time, adsorbent dosage, initial solution pH, agitation speed, natural organic matter and coexistent anions are studied. The Langmuir model can well describe CA adsorption in single-component system, while the Freundlich model gives better fitting in bi-component system. The DCF adsorption can be well fitted by the Freundlich model in both systems. Thermodynamic analyses show that the adsorption of CA and DCF is an endothermic (Delta H-degrees > 0), entropy driven (Delta S degrees > 0) process and more randomness exists in the DCF adsorption process. The values of Gibbs free energy (Delta G degrees < 0) indicate the adsorption of DCF is spontaneous but nonspontaneous (Delta G degrees > 0) for CA adsorption. The kinetic data suggest the adsorption of CA and DCF follow the pseudo-first-order model in both systems and the intra-particle is not the unique rate-limiting step. The adsorption process is controlled simultaneously by external mass transfer and surface diffusion according to the surface diffusion modified Biot number (Bi-s) ranging from 1.06 to 26.15. Moreover, the possible removal mechanism for CA and DCF is respectively proposed based on the ion exchange stoichiometry. (C) 2016 Elsevier Ltd. All rights reserved.
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