Photocatalytic degradation of herbicide isoproturon in TiO2Aqueous Suspensions: Study of Reaction Intermediates and Degradation Pathways

2013 ◽  
Vol 33 (2) ◽  
pp. 402-409 ◽  
Author(s):  
Anoop Verma ◽  
N. Tejo Prakash ◽  
Amrit Pal Toor
Keyword(s):  
Photocatalytic Degradation ◽  
Degradation Pathways ◽  
Reaction Intermediates

scholarly journals Enhanced Photocatalytic Degradation of the Imidazolinone Herbicide Imazapyr upon UV/Vis Irradiation in the Presence of CaxMnOy-TiO2 Hetero-Nanostructures: Degradation Pathways and Reaction Intermediates

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 896 ◽  
Author(s):  
Salma Bougarrani ◽  
Preetam K. Sharma ◽  
Jeremy W. J. Hamilton ◽  
Anukriti Singh ◽  
Moisés Canle ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Environmental Remediation ◽  
Irradiation Time ◽  
Radical Scavenger ◽  
Degradation Pathways ◽  
Reaction Intermediates ◽  
Mechanical Grinding ◽  
Polar Species

The determination of reaction pathways and identification of products of pollutants degradation is central to photocatalytic environmental remediation. This work focuses on the photocatalytic degradation of the herbicide Imazapyr (2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl) pyridine-3-carboxylic acid) under UV-Vis and visible-only irradiation of aqueous suspensions of CaxMnOy-TiO2, and on the identification of the corresponding degradation pathways and reaction intermediates. CaxMnOy-TiO2 was formed by mixing CaxMnOy and TiO2 by mechanical grinding followed by annealing at 500 °C. A complete structural characterization of CaxMnOy-TiO2 was carried out. The photocatalytic activity of the hetero-nanostructures was determined using phenol and Imazapyr herbicide as model pollutants in a stirred tank reactor under UV-Vis and visible-only irradiation. Using equivalent loadings, CaxMnOy-TiO2 showed a higher rate (10.6 μM·h−1) as compared to unmodified TiO2 (7.4 μM·h−1) for Imazapyr degradation under UV-Vis irradiation. The mineralization rate was 4.07 µM·h−1 for CaxMnOy-TiO2 and 1.21 μM·h−1 for TiO2. In the CaxMnOy-TiO2 system, the concentration of intermediate products reached a maximum at 180 min of irradiation that then decreased to a half in 120 min. For unmodified TiO2, the intermediates continuously increased with irradiation time with no decrease observed in their concentration. The enhanced efficiency of the CaxMnOy-TiO2 for the complete degradation of the Imazapyr and intermediates is attributed to an increased adsorption of polar species on the surface of CaxMnOy. Based on LC-MS, photocatalytic degradation pathways for Imazapyr under UV-Vis irradiation have been proposed. Some photocatalytic degradation was obtained under visible-only irradiation for CaxMnOy-TiO2. Hydroxyl radicals were found to be main reactive oxygen species responsible for the photocatalytic degradation through radical scavenger investigations.

Study on the lifetime of photocatalyst by photocatalytic membrane reactors (PMR)

2020 ◽  
Vol 81 (1) ◽  
pp. 131-137 ◽  
Author(s):  
Xiaoju Yan ◽  
Junyu Li ◽  
Cong Ma ◽  
Yu Tang ◽  
Xiangji Kong ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Membrane Reactor ◽  
Hydraulic Retention Time ◽  
Membrane Reactors ◽  
Reaction Intermediates ◽  
H2o2 Treatment ◽  
Regeneration Rate ◽  
Pore Blocking ◽  
Spent Catalysts ◽  
Degussa P25

Abstract The continuously photocatalytic degradation of methyl orange (MO) was carried out using a photocatalytic membrane reactor (PMR). The lifetime, cause of deactivation, and regeneration of Degussa P25 titanium dioxide (TiO2) were investigated. The photocatalyst was deactivated when the concentration of MO in the effluent of the PMR was stable. To characterize the lifetime of the photocatalyst, we applied g MO/g TiO2. The lifetime of the photocatalyst during the photocatalytic degradation of 10 mg/L MO was 3.71 times that of 5 mg/L MO. Changing the hydraulic retention time of the PMR from 0.75 to 3 h prolonged the lifetime of the photocatalyst. Deactivation of the photocatalyst was not due to pore blocking by the reactant (MO) or intermediate products. The surface adsorption of MO and the reaction intermediates deactivated the catalyst. The spent catalysts were regenerated after washing with methanol and hydrogen peroxide (H2O2) and then treated with heat. H2O2 treatment generated the highest regeneration rate, because H2O2 is a strong oxidizing agent that oxidized the deposited species on the surface of the photocatalyst.

Photocatalytic degradation of the herbicide clopyralid: kinetics, degradation pathways and ecotoxicity evaluation

2015 ◽  
Vol 91 (9) ◽  
pp. 2510-2518 ◽  
Author(s):  
Chrysanthi Berberidou ◽  
Vasiliki Kitsiou ◽  
Sofia Karahanidou ◽  
Dimitra A Lambropoulou ◽  
Athanasios Kouras ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Degradation Pathways

Photocatalytic degradation of boscalid in aqueous titanium dioxide suspension: Identification of intermediates and degradation pathways

2010 ◽  
Vol 98 (3-4) ◽  
pp. 122-131 ◽  
Author(s):  
Laura Lagunas-Allué ◽  
María-Teresa Martínez-Soria ◽  
Jesús Sanz-Asensio ◽  
Arnaud Salvador ◽  
Corinne Ferronato ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Degradation Pathways ◽  
Dioxide Suspension

scholarly journals Sunlight driven photocatalytic degradation of organic pollutants using a MnV2O6/BiVO4 heterojunction: mechanistic perception and degradation pathways

2021 ◽  
Author(s):  
Karina Bano ◽  
Susheel K. Mittal ◽  
Prit Pal Singh ◽  
Sandeep Kaushal
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Charge Separation ◽  
Effective Charge ◽  
Degradation Pathways ◽  
Heterojunction Structure ◽  
Charge Shift

In the field of photocatalysis, fabrication of a heterojunction structure with effective charge separation at the interface and charge shift to enhance the photocatalytic activity has acquired extensive consideration.

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