title: Heterogeneous Degradation of Organic Pollutants by Persulfate Activated by CuO-Fe3O4: Mechanism, Stability, and Effects of pH and Bicarbonate Ions.
abstract: Magnetic CuO-Fe3O4 composite was fabricated by a simple hydrothermal method and characterized as a heterogeneous catalyst for phenol degradation. The effects of pH and bicarbonate ions on catalytic activity were extensively evaluated in view of the practical applications. The results indicated that an increase of solution pH and the presence of bicarbonate ions were beneficial for the removal of phenol in the CuO-Fe3O4 coupled with persulfate (PS) process. Almost 100% mineralization of 0.1 mM phenol can be achieved in 120 min by using 0.3 g/L CuO-Fe3O4 and 5.0 mM PS at pH 11.0 or in the presence of 3.0 mM bicarbonate. The positive effect of bicarbonate ion is probably due to the suppression of copper leaching as well as the formation of Cu(III). The reuse of catalyst at pH0 11.0 and 5.6 showed that the catalyst remains a high level of stability at alkaline condition (e.g., pH0 11.0). On the basis of the characterization of catalyst, the results of metal leaching and EPR studies, it is suggested that phenol is mainly destroyed by the surface-adsorbed radicals and Cu(III) resulting from the reaction between PS and Cu(II) on the catalyst. Taking into account the widespread presence of bicarbonate ions in waste streams, the CuO-Fe3O4/PS system may provide some new insights for contaminant removal from wastewater.
authors.affiliation: †Department of Environmental Engineering, Wuhan University, Wuhan 430079, China.|‡Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Yang
authors.initials: Y
authors.lastname: Lei
authors.affiliation: ‡Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Chuh-Shun
authors.initials: CS
authors.lastname: Chen
authors.affiliation: §Institute of Urban Study, Shanghai Normal University, No.100 Guilin Rd. Shanghai 200234, China.
authors.forename: Yao-Jen
authors.initials: YJ
authors.lastname: Tu
authors.affiliation: ‡Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.|∥Sustainable Environment Research Center, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Yao-Hui
authors.initials: YH
authors.lastname: Huang
authors.affiliation: †Department of Environmental Engineering, Wuhan University, Wuhan 430079, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
mesh_terms: D001639:Bicarbonates / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008855:Microscopy, Electron, Scanning; D009930:Organic Chemicals / Q000737:chemistry*; D010084:Oxidation-Reduction; D019800:Phenol / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D013431:Sulfates / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001639:Bicarbonates; D004785:Environmental Pollutants; D005290:Ferric Compounds; D007477:Ions; D009930:Organic Chemicals; D013431:Sulfates; C000499:ferric oxide; D019800:Phenol; D003300:Copper; C030973:cupric oxide