title: Preparation of a magnetic N-Fe/AC catalyst for aqueous pharmaceutical treatment in heterogeneous sonication system.
abstract: High efficiency and facile separation are desirable for catalysts used in water treatment. In this study, a magnetic catalyst (nitrogen doped iron/activated carbon) was prepared and used for pharmaceutical wastewater treatment. The catalyst was characterized using BET, SEM, XRD, VSM and XPS. Results showed that iron and nitrogen were successfully loaded and doped, magnetic Fe2N was formed, large amount of active surface oxygen and Fe(II) were detected, and the catalyst could be easily separated from water. Diclofenac was then degraded using the catalyst in ultrasound system. The catalyst showed high catalytic activity with 95% diclofenac removal. Analysis showed that ·OH attack of diclofenac was a main pathway, and then ·OH generation mechanism was clarified. The effects of catalyst dosage, sonication time, ultrasonic density, initial pH, and inorganic anions on diclofenac degradation were studied. Sulfate anion enhanced the degradation of diclofenac. Mechanism in the catalytic ultrasonic process was analyzed and reactions were clarified. Large quantity of oxidants was generated on the catalyst surface, including ·OH, O2-, O-and HO2·, which degraded diclofenac efficiently. In the solution and interior of cavitation bubbles, ·OH and "hot spot" effects contributed to the degradation of diclofenac. Reuse of the catalyst was further investigated to enhance its economy, and the catalyst maintained activity after seven uses.
authors.affiliation: School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing 100872, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.affiliation: School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing 100872, China.
authors.forename: He
authors.initials: H
authors.lastname: Zhao
authors.affiliation: School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing 100872, China. Electronic address: zgm@ruc.edu.cn.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhang
authors.affiliation: School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing 100872, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Chong
authors.affiliation: School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing 100872, China.
authors.forename: Yucan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing 100872, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Sun
authors.affiliation: School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing 100872, China.
authors.forename: Huazhen
authors.initials: H
authors.lastname: Chang
authors.affiliation: School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing 100872, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Huang
mesh_terms: D000838:Anions; D002384:Catalysis; D002606:Charcoal / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004008:Diclofenac / Q000032:analysis*; D005240:Feasibility Studies; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D016877:Oxidants / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000032:analysis*; D013010:Sonication; D013431:Sulfates / Q000737:chemistry; D014465:Ultrasonics; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D000838:Anions; D002606:Charcoal; D004008:Diclofenac; D006878:Hydroxides; D007501:Iron; D016877:Oxidants; D004364:Pharmaceutical Preparations; D013431:Sulfates; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Diclofenac; Heterogeneous sonication; Mechanism; Nitrogen doped iron/activated carbon; Reuse; ·OH