title: Electrochemical degradation of microcystin-LR.
abstract: Microcystin-LR present in drinking water sources poses a considerable threat to human health. Conventional oxidation treatment systems, such as photocatalysis and ferrate oxidation, demonstrated the formation of by-products detectable in the treated microcystin-LR solution. This study investigated an electrochemical approach for microcystin-LR oxidation. The oxidation rate of microcystin-LR increased with the current; the oxidation rate was 0.219 min(-1) and the half-life was 2.5 min at an applied current of 100 mA to treat 1.0 mgL(-1) of microcystin-LR solution. These results were almost the same as those obtained from the photocatalytic oxidation of a 0.055 mgL(-1) microcystin-LR solution. The average instantaneous current efficiency of currents from 30 to 150 mA was greatest at 100 mA because both the current and the microcystin-LR concentration limited the oxidation rate. In addition, no by-products were detected by HPLC, which suggests that the microcystin-LR can be decomposed completely by the indirect oxidation of the hydroxyl radicals formed during electrochemical treatment. We demonstrated that the electrochemical oxidation is a promising approach for the complete oxidation of microcystin-LR.
authors.affiliation: Science and Technology Promotion Foundation of Ibaraki, Ibaraki, Japan. fchuanpg@i-step.org
authors.forename: Chuanping
authors.initials: C
authors.lastname: Feng
authors.forename: Norio
authors.initials: N
authors.lastname: Sugiura
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Masaoka
authors.forename: Takaaki
authors.initials: T
authors.lastname: Maekawa
mesh_terms: D001427:Bacterial Toxins; D000458:Cyanobacteria; D004563:Electrochemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D008387:Marine Toxins; D052998:Microcystins; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D010456:Peptides, Cyclic / Q000737:chemistry*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D018508:Water Purification / Q000379:methods*
chemical_list: D001427:Bacterial Toxins; D008387:Marine Toxins; D052998:Microcystins; D016877:Oxidants; D010456:Peptides, Cyclic; D017665:Hydroxyl Radical; D010749:Phosphoprotein Phosphatases; C057862:cyanoginosin LR