title: Zero valent iron mediated degradation of the pharmaceutical diazepam.
abstract: Parameters that influence the zero valent iron mediated degradation of the pharmaceutical diazepam (DZP) were evaluated including the iron concentration and its pre-treatment, the effect of complexation with EDTA and oxic versus anoxic condition. It was observed that acid pre-treatment of iron particles is important for degradation efficiency and that H(2)SO(4) is a better choice than HCl, resulting in higher degradation of DZP. Under oxic conditions, the degradation of DZP achieved 96% after 60 min using Fe(0) (25 g L(-1)) pre-treated with H(2)SO(4) in the presence of EDTA (119 mg L(-1)), while mineralization achieved around 60% after the same time. Under anoxic conditions, degradation occurred, however at lower extent, achieving 67% after 120 min. The addition of EDTA improved the treatment efficiency in 20% leading to 99% DZP degradation after 120 min. The first intermediates formed during DZP degradation were identified using LC/MS analysis and revealed the formation of mono- and di-hydroxylated products from DZP during Fe(0)/EDTA/O(2) degradation, which evidences that (·)OH was the main oxidizing species formed in this process.
authors.affiliation: Department of Analytical Chemistry, Institute of Chemistry of Araraquara, UNESP - Univ Estadual Paulista, CP 355, 14801-970 Araraquara, SP, Brazil.
authors.forename: Ivonete Rossi
authors.initials: IR
authors.lastname: Bautitz
authors.forename: Adriana C
authors.initials: AC
authors.lastname: Velosa
authors.forename: Raquel F Pupo
authors.initials: RF
authors.lastname: Nogueira
mesh_terms: D002845:Chromatography; D003975:Diazepam / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D004785:Environmental Pollutants / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D004492:Edetic Acid; D007501:Iron; D003975:Diazepam; D010100:Oxygen