title: Catalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) by nano-Fe2O3activated peroxymonosulfate: Influential factors and mechanism determination.
abstract: 2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most applicable herbicides in the world. Therefore, its residue in aquatic environment threatens the human health and ecosystems. In this study, Fe2O3(hematite) nanoparticles (HNPs) were synthesized, and the characteristics of the obtained HNPs were determined using X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) technique, and particle size analyzer (PSA). The catalytic activity of HNPs was evaluated for the activation of peroxymonosulfate (PMS) for the degradation of 2,4-D. The effects of the operating parameters were studied for the PMS/HNPs system. The results showed that the acidic condition provided higher efficiency, while overdosing of PMS had a scavenging effect. The PMS/HNPs showed high efficiency in comparison with the homogeneous forms of iron (Fe2+and Fe3+). Reusability of HNPs was studied in five consequent usages. The presence of the anions (chloride, nitrate, and hydrogen phosphate) reduced the 2,4-D degradation. Moreover, the catalytic activity of HNPs was also investigated in the presence of other oxidants. UV irradiation increased the function of PMS/HNPs and its mechanism was described. The order of 2,4-D removal for the oxidants was PMS > persulfate > H2O2> percarbonate. A total of 29.7% of 2,4-D chlorine content was released during the destruction of 2,4-D. The quenching study showed that sulfate radical was the major agent in the degradation of 2,4-D.
authors.affiliation: Environmental Technologies Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Nematollah
authors.initials: N
authors.lastname: Jaafarzadeh
authors.affiliation: Environmental Technologies Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Electronic address: Ghanbari.env@gmail.com.
authors.forename: Farshid
authors.initials: F
authors.lastname: Ghanbari
authors.affiliation: Environmental Technologies Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Ahmadi
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis* / Q000528:radiation effects; D002384:Catalysis; D005290:Ferric Compounds / Q000737:chemistry*; D008956:Models, Chemical; D053758:Nanoparticles / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry; D013499:Surface Properties; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000528:radiation effects
chemical_list: D005290:Ferric Compounds; D016877:Oxidants; D010545:Peroxides; D013431:Sulfates; D014874:Water Pollutants, Chemical; C069025:sulfate radical; C000499:ferric oxide; C038288:peroxymonosulfate; D015084:2,4-Dichlorophenoxyacetic Acid
keywords: 2,4-Dichlorophenoxyacetic acid; Hematite; Peroxymonosulfate; Photocatalysis; Sulfate radical