Photocatalytic Degradation of 4-Chlorophenol by •OH Radicals Generated by Thiophene Oligomers Incorporated in ZSM-5 Zeolite Channels

2003 ◽  
Vol 68 (11) ◽  
pp. 2219-2230 ◽  
Author(s):  
Gabriel Čík ◽  
Milada Hubinová ◽  
František Šeršeň ◽  
Jozef Krištín ◽  
Monika Antošová
Keyword(s):  
Reactive Oxygen Species ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Maleic Acid ◽  
Aqueous Suspension ◽  
Reactive Oxygen ◽  
Spin Trapping ◽  
Oh Radicals ◽  
Oxygen Species ◽  
Trapping Method

Degradation of 4-chlorophenol by reactive oxygen species was studied, the latter being generated by photo-assisted reactions of thiophene oligomers, synthesized in channels of the Na-ZSM-5 zeolite. The photoreaction was carried out in an aqueous suspension of photocatalyst, irradiated with visible light (λ > 400 nm). The spin-trapping method was used to detect the generated •OH radicals. The main products of the photodecomposition of 4-chlorophenol were found to be phenol, hydroquinone and maleic acid.

Fabrication of magnetic BaFe12O19/Ag3PO4 composites with an in situ photo-Fenton-like reaction for enhancing reactive oxygen species under visible light irradiation

2019 ◽  
Vol 9 (10) ◽  
pp. 2563-2570 ◽  
Author(s):  
Yuanguo Xu ◽  
Feiyue Ge ◽  
Meng Xie ◽  
Shuquan Huang ◽  
Junchao Qian ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Reactive Oxygen ◽  
Light Irradiation ◽  
Oh Radicals ◽  
Oxygen Species

An in situ photo-Fenton-like and magnetic recycle system, BaFe12O19/Ag3PO4 has been constructed. BaFe12O19 can catalyze the conversion of H2O2 to generate ROSs (˙O2− and ˙OH radicals) on the surface of Ag3PO4.

Mechanism of CeVO4/TiO2 Photocatalytic Degradation of VOCs under Visible Light Irradiation: Electrochemical, Photoluminescence and Active Oxygen Species Study

2012 ◽  
Vol 217-219 ◽  
pp. 853-856 ◽  
Author(s):  
Han Jie Huang ◽  
Wen Long She ◽  
Ling Wen Yang
Keyword(s):  
Reactive Oxygen Species ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Gas Phase ◽  
Degradation Mechanism ◽  
Active Oxygen Species ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Composite Photocatalyst ◽  
Photocatalytic Degradation Mechanism

In this paper, CeVO4/TiO2 composite photocatalyst has been characterized by photoelectrochemical and reactive oxygen species trap techniques to reveal the mechanism for photocatalytic degradation of VOCs in gas-phase. Based on the measurement of flatband of the samples and the detection of reactive oxygen species, a visible light-induced photocatalytic degradation mechanism of VOCs on CeVO4/TiO2 is proposed.

scholarly journals Photocatalytic Performance of CuxO/TiO2 Deposited by HiPIMS on Polyester under Visible Light LEDs: Oxidants, Ions Effect, and Reactive Oxygen Species Investigation

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 412 ◽  
Author(s):  
Hichem Zeghioud ◽  
Aymen Assadi ◽  
Nabila Khellaf ◽  
Hayet Djelal ◽  
Abdeltif Amrane ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Magnetron Sputtering ◽  
Visible Light ◽  
Metallic Nanoparticles ◽  
Reaction Rate ◽  
Potassium Dichromate ◽  
Reactive Oxygen ◽  
Oh Radicals ◽  
Primary Role ◽  
Oxygen Species

In the present study, we propose a new photocatalytic interface prepared by high-power impulse magnetron sputtering (HiPIMS), and investigated for the degradation of Reactive Green 12 (RG12) as target contaminant under visible light light-emitting diodes (LEDs) illumination. The CuxO/TiO2 nanoparticulate photocatalyst was sequentially sputtered on polyester (PES). The photocatalyst formulation was optimized by investigating the effect of different parameters such as the sputtering time of CuxO, the applied current, and the deposition mode (direct current magnetron sputtering, DCMS or HiPIMS). The results showed that the fastest RG12 degradation was obtained on CuxO/TiO2 sample prepared at 40 A in HiPIMS mode. The better discoloration efficiency of 53.4% within 360 min was found in 4 mg/L of RG12 initial concentration and 0.05% Cuwt/PESwt as determined by X-ray fluorescence. All the prepared samples contained a TiO2 under-layer with 0.02% Tiwt/PESwt. By transmission electron microscopy (TEM), both layers were seen uniformly distributed on the PES fibers. The effect of the surface area to volume (dye volume) ratio (SA/V) on the photocatalytic efficiency was also investigated for the discoloration of 4 mg/L RG12. The effect of the presence of different chemicals (scavengers, oxidant or mineral pollution or salts) in the photocatalytic medium was studied. The optimization of the amount of added hydrogen peroxide (H2O2) and potassium persulfate (K2S2O8) was also investigated in detail. Both, H2O2 and K2S2O8 drastically affected the discoloration efficiency up to 7 and 6 times in reaction rate constants, respectively. Nevertheless, the presence of Cu (metallic nanoparticles) and NaCl salt inhibited the reaction rate of RG12 discoloration by about 4 and 2 times, respectively. Moreover, the systematic study of reactive oxygen species’ (ROS) contribution was also explored with the help of iso-propanol, methanol, and potassium dichromate as •OH radicals, holes (h+), and superoxide ion-scavengers, respectively. Scavenging results showed that O2− played a primary role in RG12 removal; however, •OH radicals’ and photo-generated holes’ (h+) contributions were minimal. The CuxO/TiO2 photocatalyst was found to have a good reusability and stability up to 21 cycles. Ions’ release was quantified by means of inductively coupled plasma mass spectrometry (ICP-MS) showing low Cu-ions’ release.

scholarly journals Evaluation of the reactive oxygen species scavenging abilities of tomato juice using ESR spin trapping method

2017 ◽  
Vol 27 (4) ◽  
pp. 267-272 ◽  
Author(s):  
Hiromi Kameya ◽  
Toshihiko Shoji ◽  
Yuji Otagiri ◽  
Akio Obata ◽  
Vipavee Trivittayasil ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Spin Trapping ◽  
Tomato Juice ◽  
Oxygen Species ◽  
Esr Spin Trapping ◽  
Trapping Method

Investigating the DMPO-formate spin trapping method for the study of paper iron gall ink corrosion

2016 ◽  
Vol 40 (11) ◽  
pp. 9098-9110 ◽  
Author(s):  
Alice Gimat ◽  
Valeryia Kasneryk ◽  
Anne-Laurence Dupont ◽  
Sabrina Paris ◽  
Frédéric Averseng ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydroxyl Radicals ◽  
Reactive Oxygen ◽  
Spin Trapping ◽  
Oxygen Species ◽  
Paper Degradation ◽  
Trapping Method ◽  
Iron Gall

Reactive oxygen species evidenced in acidic iron gall inks are not hydroxyl radicals and are not linked to paper degradation.

Photoassisted Production of O2-• and H2 in Aqueous Medium Stimulated by Polythiophene in ZSM-5 Zeolite Channels

1999 ◽  
Vol 64 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Gabriel Čík ◽  
František Šeršeň ◽  
Alena Bumbálová
Keyword(s):  
Reactive Oxygen Species ◽  
Ion Exchange ◽  
Visible Light ◽  
Aqueous Medium ◽  
Exchange Reaction ◽  
Epr Spectroscopy ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Water Reduction ◽  
Ion Exchange Reaction

The formation of reactive oxygen species due to irradiation by a visible light of the polythiophene deposited in ZSM-5 zeolite channels in aqueous medium has been studied. Polymerization of thiophene was carried out in zeolite channels after the ion-exchange reaction of Na+ for Fe3+. By means of EPR spectroscopy, the temporarily generated 1O2 in irradiated aqueous medium was proved. The formation of O2-• was confirmed by the reduction of Fe3+-cytochrome c. Irradiation led to the water reduction to hydrogen.

scholarly journals Photo-Responsive Supramolecular Micelles for Controlled Drug Release and Improved Chemotherapy

2020 ◽  
Vol 22 (1) ◽  
pp. 154
Author(s):  
Fasih Bintang Ilhami ◽  
Kai-Chen Peng ◽  
Yi-Shiuan Chang ◽  
Yihalem Abebe Alemayehu ◽  
Hsieh-Chih Tsai ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Drug Release ◽  
Visible Light ◽  
Cancer Cells ◽  
Laser Irradiation ◽  
Reactive Oxygen ◽  
Controlled Drug Release ◽  
Grand Challenge ◽  
Supramolecular System ◽  
Oxygen Species

Development of stimuli-responsive supramolecular micelles that enable high levels of well-controlled drug release in cancer cells remains a grand challenge. Here, we encapsulated the antitumor drug doxorubicin (DOX) and pro-photosensitizer 5-aminolevulinic acid (5-ALA) within adenine-functionalized supramolecular micelles (A-PPG), in order to achieve effective drug delivery combined with photo-chemotherapy. The resulting DOX/5-ALA-loaded micelles exhibited excellent light and pH-responsive behavior in aqueous solution and high drug-entrapment stability in serum-rich media. A short duration (1–2 min) of laser irradiation with visible light induced the dissociation of the DOX/5-ALA complexes within the micelles, which disrupted micellular stability and resulted in rapid, immediate release of the physically entrapped drug from the micelles. In addition, in vitro assays of cellular reactive oxygen species generation and cellular internalization confirmed the drug-loaded micelles exhibited significantly enhanced cellular uptake after visible light irradiation, and that the light-triggered disassembly of micellar structures rapidly increased the production of reactive oxygen species within the cells. Importantly, flow cytometric analysis demonstrated that laser irradiation of cancer cells incubated with DOX/5-ALA-loaded A-PPG micelles effectively induced apoptotic cell death via endocytosis. Thus, this newly developed supramolecular system may offer a potential route towards improving the efficacy of synergistic chemotherapeutic approaches for cancer.

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