title: Degradation of microcystins in aqueous solution with in situ electrogenerated active chlorine.
abstract: A new and efficient method for the degradation of microcystins (one family of blue algal toxins) was developed and studied. Microcystins (MCs) in water were directly and effectively removed by active chlorine transformed in situ from the naturally existing Cl- in water resource using electrochemical method. Titanium coated with RuO2 and TiO2 was used as the anode. Microcystin-RR (MCRR) and Microcystin-LR (MCLR) were chosen as the model compounds of MCs. The results suggested that 20.87 mgl(-1) MCs (12.58 mgl(-1) MCRR and 8.29 mgl(-1) MCLR) in aqueous solution with 1.85 mM Cl- could be synchronously decomposed within 15 min electrolysis under the condition of the current density 8.89 mAcm(-2), 20 degrees C and pH 7.00. The qualitative analysis showed that the heptapetide ring and the Adda group of both treated MCs were changed. The results also indicated that the removal rates of both MCs increased with the increasing of chloride concentration and applied current density, but decreased with the increasing of initial concentration of MCs and initial pH of electrolyte. In the absence of Cl-, only a small fraction of both MCs were decomposed by direct anodic oxidation, while their almost complete removals could be obtained in the case of indirect electrooxidation with in situ electrogenerated active chlorine from Cl- in water.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Hong-Xing
authors.initials: HX
authors.lastname: Shi
authors.forename: Jiu-Hui
authors.initials: JH
authors.lastname: Qu
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Wang
authors.forename: Jian-Tuan
authors.initials: JT
authors.lastname: Ge
mesh_terms: D002713:Chlorine / Q000737:chemistry*; D000458:Cyanobacteria; D004563:Electrochemistry; D004566:Electrodes; D008387:Marine Toxins; D052998:Microcystins; D010084:Oxidation-Reduction; D010456:Peptides, Cyclic / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D014874:Water Pollutants, Chemical; D002713:Chlorine; C063855:microcystin RR; C057862:cyanoginosin LR