title: Photodegradation of microcystin-LR catalyzed by metal phthalocyanines immobilized on TiO2-SiO2 under visible-light irradiation.
abstract: Microcystins (MCs) are a group of monocyclic heptapeptide toxins produced by species of cyanobacteria. Since MCs exhibit acute and chronic effects on humans and wildlife by damaging the liver, they are of increasing concern worldwide. In this study, we investigated the ability of the phthalocyanine compound (ZnPc-TiO2-SiO2) to degrade microcystin-LR (MC-LR) in the presence of visible light. X-ray diffraction (XRD) and UV-Visible diffuse reflectance spectra (UV-Vis DRS) were utilized to characterize the crystalline phase and the absorption behavior of this catalyst. According to the results, XRD spectra of ZnPc-TiO2-SiO2 powders taken in the 2θ configuration exhibited the peaks characteristic of the anatase phase. UV-Vis DRS showed that the absorption band wavelength shifted to the visible range when ZnPc was supported on the surface of TiO2-SiO2. Subsequently, several parameters including catalyst dose, MC-LR concentrations and pH were investigated. The MC-LR was quantified in each sample through high-performance liquid chromatography (HPLC). The maximum MC-LR degradation rate of 80.2% can be obtained within 300 minutes under the following conditions: catalyst dose of 7.50 g/L, initial MC-LR concentration of 17.35 mg/L, pH 6.76 and the first cycling run of the photocatalytic reaction. Moreover, the degradation process fitted well with the pseudo-first-order kinetic model.
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Room 314, No. 220 Handan Road, Yangpu District, Shanghai 200433, China E-mail: xrxrwang@vip.sina.com.
authors.forename: Guotao
authors.initials: G
authors.lastname: Peng
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Room 314, No. 220 Handan Road, Yangpu District, Shanghai 200433, China E-mail: xrxrwang@vip.sina.com.
authors.forename: Zhengqiu
authors.initials: Z
authors.lastname: Fan
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Room 314, No. 220 Handan Road, Yangpu District, Shanghai 200433, China E-mail: xrxrwang@vip.sina.com.
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Room 314, No. 220 Handan Road, Yangpu District, Shanghai 200433, China E-mail: xrxrwang@vip.sina.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Sui
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Room 314, No. 220 Handan Road, Yangpu District, Shanghai 200433, China E-mail: xrxrwang@vip.sina.com.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
mesh_terms: D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D008027:Light; D008387:Marine Toxins; D052998:Microcystins / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D010782:Photolysis; D012822:Silicon Dioxide / Q000737:chemistry*; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D007211:Indoles; D054833:Isoindoles; D008387:Marine Toxins; D052998:Microcystins; D009942:Organometallic Compounds; C507641:TiO2-SiO2; C063072:zinc(II) phthalocyanine trisulfonic acid; D012822:Silicon Dioxide; D014025:Titanium; C057862:cyanoginosin LR; C013647:phthalocyanine