Photocatalytic degradation of persistent organic pollutants under visible irradiation by TiO2 catalysts sensitized with Zn(II) and Co(II) tetracarboxy-phthalocyanines

2016 ◽  
Vol 20 (08n11) ◽  
pp. 1190-1199 ◽  
Author(s):  
Yaghub Mahmiani ◽  
Altuğ Mert Sevim ◽  
Ahmet Gül
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Diffuse Reflectance Spectroscopy ◽  
Aqueous Media ◽  
Visible Region ◽  
Gas Chromatography Mass Spectrometry ◽  
Infrared Spectrometry ◽  
Visible Irradiation ◽  
The Difference

Photo-excitation under visible light has been an important step to acquire solar-driven TiO2 photocatalysts and dye sensitization has been used frequently to extend the optical response of TiO2 into the visible region. In the present work, new heterogeneous photocatalysts were prepared by anchoring carboxylic acid substituted Zn(II) and Co(II) phthalocyanines onto polycrystalline TiO2 surface and their photocatalytic activities were investigated. Due to covalent bonding of carboxy-terminated molecules onto TiO[Formula: see text]semiconductors, we synthesized symmetric 4-hydroxybenzoic acid-bearing metallophthalocyanines as dye sensitizer molecules. Heterogeneous composites having titanium dioxide and metallophthalocyanines anchored via CO–O–TiO2 bonds were characterized by using X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FT-IR), and ultraviolet-visible diffuse reflectance spectroscopy. The optimum loading value of the dyes on TiO2 were 0.98 [Formula: see text]mol/g TiO2 for CoPc and 0.86 [Formula: see text]mol/g TiO2 for ZnPc, nearly independent of the amount of TiO2 used. These newly obtained heterogeneous photocatalysts were employed in the photocatalytic degradation of 4-chlorophenol(4-CP), chlorobenzene(CB) and 1,2,4-trichlorobenzen(TCB) in aqueous media under visible irradiation. Gas chromatography-mass spectrometry (GC-MS) was used for quantitation. The new photocatalysts showed excellent activities with visible-region irradiation in the photocatalytic degradation of persistent organic pollutants (POPs) as compared to the control experiments used with untreated TiO2 and the difference was attributed to the cooperation of the two elements, namely TiO2 and MPc. Experiments show that in two hours nearly complete degradation of POPs were observed.

scholarly journals Application of BiOX Photocatalysts in Remediation of Persistent Organic Pollutants

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 604 ◽  
Author(s):  
Robert Arthur ◽  
John Ahern ◽  
Howard Patterson
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Radical Scavenging ◽  
Flow Chemistry ◽  
Active Species ◽  
Effective Strategies ◽  
Degradation Of Dyes ◽  
Bismuth Oxyhalides ◽  
Electron Holes

Bismuth oxyhalides have recently gained attention for their promise as photocatalysts. Due to their layered structure, these materials present fascinating and highly desirable physicochemical properties including visible light photocatalytic capability and improved charge separation. While bismuth oxyhalides have been rigorously evaluated for the photocatalytic degradation of dyes and many synthesis strategies have been employed to enhance this property, relatively little work has been done to test them against pharmaceuticals and pesticides. These persistent organic pollutants are identified as emerging concerns by the EPA and effective strategies must be developed to combat them. Here, we review recent work directed at characterizing the nature of the interactions between bismuth oxyhalides and persistent organic pollutants using techniques including LC-MS/MS for the determination of photocatalytic degradation intermediates and radical scavenging to determine active species during photocatalytic degradation. The reported investigations indicate that the high activity of bismuth oxyhalides for the breakdown of persistent organic pollutants from water can be largely attributed to the strong oxidizing power of electron holes in the valence band. Unlike conventional catalysts like TiO2, these catalysts can also function in ambient solar conditions. This suggests a much wider potential use for these materials as green catalysts for industrial photocatalytic transformation, particularly in flow chemistry applications.

STUDY CONCERNING THE INFLUENCE OF OXIDIZING AGENTS ON HETEROGENEOUS PHOTOCATALYTIC DEGRADATION OF PERSISTENT ORGANIC POLLUTANTS

2007 ◽  
Vol 6 (6) ◽  
pp. 483-489 ◽  
Author(s):  
Anca Florentina Caliman ◽  
Camelia Betianu ◽  
Brindusa Mihaela Robu ◽  
Maria Gavrilescu ◽  
Ioannis Poulios
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Oxidizing Agents

Visible light induced enhanced photocatalytic degradation of organic pollutants in aqueous media using Ag doped hollow TiO2 nanospheres

RSC Advances ◽  
2015 ◽  
Vol 5 (47) ◽  
pp. 37657-37668 ◽  
Author(s):  
Siddhartha Sankar Boxi ◽  
Santanu Paria
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Organic Compounds ◽  
Organic Pollutants ◽  
Aqueous Media ◽  
Nano Catalyst

Visible light induced photocatalytic degradation of organic compounds using silver doped hollow TiO2 nano-catalyst.

scholarly journals Persistent Organic Pollutants in Serum and Several Different Fat Compartments in Humans

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
George W. Yu ◽  
John Laseter ◽  
Charles Mylander
Keyword(s):  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Polychlorinated Biphenyl ◽  
Elective Surgery ◽  
Human Subjects ◽  
Subcutaneous Fat ◽  
Abdominal Fat ◽  
Chlorinated Pesticides ◽  
Pcb Congeners ◽  
The Difference

Background. Chemicals that store in lipid-rich compartments have the potential for long-term disruption of metabolic and endocrine processes. Given the evidence that persistent organic pollutants (POPs) also alter systemic metabolic, endocrine, and immune system functions, it follows that elevated chemical concentrations in intra-abdominal fat may alter function, through local chemical signaling, of visceral organs. Despite this potential, there has been little study defining POP concentrations in live human intra-abdominal fat. It is at present uncertain whether POPs distribute equally to all fat compartments, including fat in serum.Methods. Seven human subjects scheduled for elective surgery for benign lesions or cancer provided consent for removal of samples of subcutaneous and intra-abdominal fat and/or cancerous tissue. These samples were analyzed for 22 chlorinated pesticides and 10 polychlorinated biphenyl (PCB) congeners by GC/ECD plus GC/MS.Results. In only two subjects were the patterns and relative concentrations of PCBs and pesticides about the same in all fat compartments. In the other subjects, there were major differences in levels in subcutaneous as compared to other compartments, but with some higher and some lower. While the pattern of PCBs in the various compartments matched that of the pesticides in some, it was opposite in others.Interpretation. These results demonstrate a complicated distribution of PCB congeners and pesticides in various lipid compartments. The difference may reflect various Kows, different rates of metabolism, and/or different lengths of exposure. But the results suggest that contaminant levels in serum or even subcutaneous fat do not necessarily indicate concentrations and patterns in other kinds of adipose tissue.

scholarly journals Structurally and Compositionally Tunable Absorption Properties of AgCl@AgAu Nanocatalysts for Plasmonic Photocatalytic Degradation of Environmental Pollutants

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 405
Author(s):  
Han-Jung Ryu ◽  
Ha-Lin Kim ◽  
Jang Ho Joo ◽  
Jae-Seung Lee
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Aqueous Media ◽  
Environmental Pollutants ◽  
Selective Reduction ◽  
Visible Range ◽  
Ag Nps ◽  
Absorption Bands ◽  
Visible Light Driven

Composite nanomaterials having Ag nanoparticles (NPs) that decorate nanostructured AgCl (Ag/AgCl) are promising as plasmonic photocatalysts because of the visible-light absorption of Ag NPs. However, the narrow absorption bands of Ag NPs near 400 nm cause inefficient absorption in the visible range and, consequently, unsatisfactory photocatalytic activity of Ag/AgCl nanomaterials. In this study, we introduce a new class of AgCl-based photocatalysts that are decorated with bimetallic Ag and Au NPs (AgCl@AgAu NPs) for visible-light-driven photocatalytic degradation of organic pollutants. Polyvinylpyrrolidone induces selective reduction of noble metal precursors on AgCl while leaving AgCl intact. The extended composition of the decorating NPs red-shifts the absorption band to 550–650 nm, which allows the catalysts to take advantage of more energy in the visible range for improved efficiency. Furthermore, we control the structures of the AgCl@AgAu NPs, and investigate their correlation with photocatalytic properties. The versatility, chemical stability, and practical application of the AgCl@AgAu NPs are demonstrated using various organic pollutants, recycling experiments, and natural aqueous media, respectively. Our fundamental investigation on the synthesis and applications of AgCl-based nano-photocatalysts is highly valuable for designing plasmonic photocatalysts and expanding their utilization.

scholarly journals Synthesis of TiO2/Carbon Nanoparticle (C-dot) Composites as Active Catalysts for Photodegradation of Persistent Organic Pollutant

2017 ◽  
Vol 17 (1) ◽  
pp. 37 ◽  
Author(s):  
Dedri Syafei ◽  
Sri Sugiarti ◽  
Noviyan Darmawan ◽  
Mohammad Khotib
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Visual Analysis ◽  
Organic Pollutant ◽  
Sol Gel ◽  
Synthesis Product ◽  
Photoluminescence Properties ◽  
Carbon Nanoparticle ◽  
Sunlight Irradiation

TiO2/C-dot composites were synthesised by sol-gel method and  investigated as catalysts for photocatalytic degradation of persistent organic pollutants (perchloroethylene, PCE). The composites photoluminescence properties was shown by visual analysis and the synthesis product was characterized by XRD, FTIR, fluorescence spectrophotometer, and UV-Vis spectrophotometer. Degradation of PCE 0.1% (v/v) in the aqueous phase was investigated under sunlight irradiation for 2 h. Photodegrade efficiency of PCE was determined by GC. Composites of TiO2/C-dot 2.5% (w/w) was succesfully to degrade PCE under sunlight irradiation and its photodegrade efficiency was up to 89.45%.

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