scholarly journals Investigation of the Aquatic Photolytic and Photocatalytic Degradation of Citalopram

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5331
Author(s):  
Cristina Jiménez-Holgado ◽  
Paola Calza ◽  
Debora Fabbri ◽  
Federica Dal Bello ◽  
Claudio Medana ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Natural Waters ◽  
Vibrio Fischeri ◽  
Degradation Process ◽  
Transformation Products ◽  
Operating Conditions ◽  
Solar Irradiation ◽  
Photochemical Degradation ◽  
Indirect Photolysis ◽  
Water Constituents

This study investigated the direct and indirect photochemical degradation of citalopram (CIT), a selective serotonin reuptake inhibitor (SSRI), under natural and artificial solar radiation. Experiments were conducted in a variety of different operating conditions including Milli-Q (MQ) water and natural waters (lake water and municipal WWT effluent), as well as in the presence of natural water constituents (organic matter, nitrate and bicarbonate). Results showed that indirect photolysis can be an important degradation process in the aquatic environment since citalopram photo-transformation in the natural waters was accelerated in comparison to MQ water both under natural and simulated solar irradiation. In addition, to investigate the decontamination of water from citalopram, TiO2-mediated photocatalytic degradation was carried out and the attention was given to mineralization and toxicity evaluation together with the identification of by-products. The photocatalytic process gave rise to the formation of transformation products, and 11 of them were identified by HPLC-HRMS, whereas the complete mineralization was almost achieved after 5 h of irradiation. The assessment of toxicity of the treated solutions was performed by Microtox bioassay (Vibrio fischeri) and in silico tests showing that citalopram photo-transformation involved the formation of harmful compounds.

scholarly journals Photocatalytic Degradation of Monolinuron and Linuron in an Aqueous Suspension of Titanium Dioxide Under Simulated Solar Irradiation

2007 ◽  
Vol 20 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Razika Zouaghi ◽  
Abdennour Zertal ◽  
Bernard David ◽  
Sylvie Guittonneau
Keyword(s):  
Photocatalytic Degradation ◽  
Degradation Rate ◽  
Ph Value ◽  
Degradation Kinetics ◽  
Aqueous Suspension ◽  
Operating Conditions ◽  
Solar Irradiation ◽  
Point Of Zero Charge ◽  
Degradation Rates ◽  
Simulated Solar Irradiation

Abstract The photocatalytic degradation of two phenylurea herbicides, monolinuron (MLN) and linuron (LN), was investigated in an aqueous suspension of TiO2 using simulated solar irradiation. The objective of the study was to compare their photocatalytic reactivity and to assess the influence of various parameters such as initial pesticide concentration, catalyst concentration and photonic flux on the photocatalytic degradation rate of MLN and LN. A comparative study of the photocatalytic degradation kinetics of both herbicides showed that these two compounds have a comparable reactivity with TiO2/simulated sun light. Under the operating conditions of this study, the photocatalytic degradation of MLN and LN followed pseudo first-order decay kinetics. The kobs values indicated an inverse dependence on the initial herbicide concentration and were fitted to the Langmuir-Hinshelwood equation. Photocatalytic degradation rates increased with TiO2 dosage, but overdoses did not necessarily increase the photocatalytic efficiency. The degradation rate of MLN increased with radiant flux until an optimum at 580 W m‑2 was reached and then decreased. Under these conditions, an electron-hole recombination was favored. Finally, the photocatalytic degradation rate depended on pH, where an optimum was found at a pH value close to the pH of the point of zero charge (pH = 6).

Carbon Coated TiO2 and it Application on Photodegradation of 4-Chlorophenol under Solar Irradiation

2015 ◽  
Vol 754-755 ◽  
pp. 1202-1206
Author(s):  
Wan Izhan Nawawi ◽  
H.K.N. Mahrouqi ◽  
M.A. Nawi ◽  
Mohd Azlan Mohd Ishak ◽  
Ali H. Jawad ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Degradation Process ◽  
Order Rate Constant ◽  
Solar Irradiation ◽  
No Adsorption ◽  
Custom Made ◽  
Carbon Coated ◽  
Glass Cell ◽  
Cell Reactor ◽  
It Application

The photocatalytic degradation of 4-Chlorophenol (4CP) using carbon C coated TiO2 (C-TiO2) and pristine TiO2 under solar irradiation was carried out in a suspension mode under custom made glass cell reactor with continuous aeration supply. It was found that 0.3 and 0.6 g were the optimum loading for C-TiO2 and pristine TiO2 respectively in the degradation of 20 mg L-1 4CP under solar irradiation. The optimum C-TiO2 was found six times faster than pristine TiO2 based on pseudo first order rate constant of 4CP photodegradation. No adsorption was observed in the photocatalysts. The intermediates observed during this photocatalytic degradation process were maleic acid, hydroquinone (HQ), benzoquinone (BQ), 4-chlorochetol (4CC) and resorcinol.

Examination for Degradation Paths of Butyltin Compounds in Natural Waters

1992 ◽  
Vol 25 (11) ◽  
pp. 117-124 ◽  
Author(s):  
N. Watanabe ◽  
S. Sakai ◽  
H. Takatsuki
Keyword(s):  
Glass Fiber ◽  
Half Life ◽  
Natural Waters ◽  
Sea Water ◽  
Degradation Process ◽  
Distilled Water ◽  
Degradation Rates ◽  
Clean Area ◽  
Butyltin Compounds ◽  
Sun Light

Examination of individual degradation paths (biodegradation and photolysis) of butyltin compounds (especially tributyltin: TBT) in natural waters was performed. Biodegradation of TBT and dibutyltin (DBT) in an unfiltered sea water in summer is rather fast; their half life is about a week. But pretreatment with glass fiber filter makes the half life of TBT much longer (about 80 days). Photolysis of TBT in sea water by sun light is rapid (half life is about 0.5 days), and faster than in distilled water or in fresh water. Degradation rates of each process for TBT are calculated in various conditions of sea water, and contribution rates are compared. Biodegradation will be the main degradation process in an “SS-rich” area such as a marina, but photolysis will exceed that in a “clean” area. Over all half lives of TBT in sea water vary from 6 days to 127 days considering seasons and presence of SS.

scholarly journals Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1338 ◽  
Author(s):  
Klara Perović ◽  
Francis M. dela Rosa ◽  
Marin Kovačić ◽  
Hrvoje Kušić ◽  
Urška Lavrenčič Štangar ◽  
...  
Keyword(s):  
Water Treatment ◽  
Transition Metal ◽  
Photocatalytic Degradation ◽  
Water Splitting ◽  
Water Purification ◽  
Degradation Mechanism ◽  
Living Environment ◽  
Solar Irradiation ◽  
Metal Chalcogenides ◽  
Photocatalytic Water Splitting

Clean water and the increased use of renewable energy are considered to be two of the main goals in the effort to achieve a sustainable living environment. The fulfillment of these goals may include the use of solar-driven photocatalytic processes that are found to be quite effective in water purification, as well as hydrogen generation. H2 production by water splitting and photocatalytic degradation of organic pollutants in water both rely on the formation of electron/hole (e−/h+) pairs at a semiconducting material upon its excitation by light with sufficient photon energy. Most of the photocatalytic studies involve the use of TiO2 and well-suited model compounds, either as sacrificial agents or pollutants. However, the wider application of this technology requires the harvesting of a broader spectrum of solar irradiation and the suppression of the recombination of photogenerated charge carriers. These limitations can be overcome by the use of different strategies, among which the focus is put on the creation of heterojunctions with another narrow bandgap semiconductor, which can provide high response in the visible light region. In this review paper, we report the most recent advances in the application of TiO2 based heterojunction (semiconductor-semiconductor) composites for photocatalytic water treatment and water splitting. This review article is subdivided into two major parts, namely Photocatalytic water treatment and Photocatalytic water splitting, to give a thorough examination of all achieved progress. The first part provides an overview on photocatalytic degradation mechanism principles, followed by the most recent applications for photocatalytic degradation and mineralization of contaminants of emerging concern (CEC), such as pharmaceuticals and pesticides with a critical insight into removal mechanism, while the second part focuses on fabrication of TiO2-based heterojunctions with carbon-based materials, transition metal oxides, transition metal chalcogenides, and multiple composites that were made of three or more semiconductor materials for photocatalytic water splitting.

scholarly journals Preparation of Ti-Nb-Fe-O Nanotubes on Ti10NbxFe Alloy and the Application for Photocatalytic Degradation under Solar Irradiation

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 327
Author(s):  
Yujie Zhao ◽  
Qiquan Li ◽  
Yan Li
Keyword(s):  
Photocatalytic Degradation ◽  
Mixed Oxide ◽  
Tio2 Nanotubes ◽  
Degradation Rate ◽  
Solar Irradiation ◽  
Methylene Blue Degradation ◽  
Co Doping ◽  
Secondary Pollution ◽  
The Rich ◽  
Thick Layers

Highly oriented and self-ordered titanium-niobium-iron mixed oxide nanotubes were synthesized by anodizing Ti10NbxFe alloys in ethylene glycol electrolytes containing NH4F and water at 20 °C. The nanostructure morphologies were found to depend closely on the nature of the alloy substrates. The results demonstrate the possibility of growing mixed oxide nanotubes possessing several-micrometer-thick layers by a simple and straightforward electrochemical route. The methylene blue degradation rate of fabricated Ti-Nb-Fe-O nanotubes increased by 33% compared to TiO2 nanotubes and TiO2 nanoparticle films under solar irradiation. The combination of the gully-like morphology and the rich defects introduced by Nb and Fe co-doping in Ti-Nb-Fe-O mixed nanotube oxides was demonstrated to be beneficial for enhanced photocatalytic degradation performance. Ti-Nb-Fe-O nanotubes can achieve effective photodegradation without secondary pollution with more reusability than powder photocatalysts.

Photocatalytic degradation of organic dyes by Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar irradiation

2016 ◽  
Vol 90 (13) ◽  
pp. 2654-2664 ◽  
Author(s):  
Yang Chen ◽  
Chunxiao Lu ◽  
Liang Tang ◽  
Yahui Song ◽  
Shengnan Wei ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Dyes ◽  
Solar Irradiation ◽  
Doped Zno

Photolytic degradation of quinalphos in natural waters and on soil matrices under simulated solar irradiation

Chemosphere ◽  
2006 ◽  
Vol 64 (8) ◽  
pp. 1375-1382 ◽  
Author(s):  
C. Gonçalves ◽  
A. Dimou ◽  
V. Sakkas ◽  
M.F. Alpendurada ◽  
T.A. Albanis
Keyword(s):  
Natural Waters ◽  
Solar Irradiation ◽  
Photolytic Degradation ◽  
Simulated Solar Irradiation

Photocatalytic Degradation of Synthetic Sulfur Pollutants in Petroleum Fractions under Different pH and Photocatalyst

2021 ◽  
Vol 02 (01) ◽  
Author(s):  
Mohamad Alif Hakimi Hamdan ◽  
◽  
Nur Hanis Hayati Hairom ◽  
Nurhafisza Zaiton ◽  
Zawati Harun ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Zno Nanoparticles ◽  
Low Cost ◽  
Industrial Effluents ◽  
Degradation Process ◽  
Vital Role ◽  
Petroleum Fraction ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Petroleum Fractions

Thiophene is one of the sulfur compounds in the petroleum fraction that can be harmful to living things and lead to a critical effect on the ecosystem. Photocatalytic degradation is one of the promising methods in treating wastewater as it can mineralization of pollutants into carbon dioxide and water. Other than that, this method is non-toxic and relatively low cost. The production of hydroxyl radicals playing a vital role in the degradation of organic pollutants. It has been claimed that the usage of zinc oxide (ZnO) nanoparticles could give an excellent degradation process as this photocatalyst have high photosensitivity, low cost and chemically stable. However, the preparation method of ZnO nanoparticles will affect the agglomeration, particle size, shape and morphology of particles and lead to influence the photocatalytic activity in degrading thiophene. Therefore, this study focused on the effectiveness of ZnO nanoparticles in the presence of fibrous nanosilica (KCC-1) and polyethylene glycol (PEG) as the capping agent to degrade synthetic thiophene. ZnO/KCC-1 had been synthesized via the precipitation method and characterized by using Fourier Transform Infrared (FTIR). The chemical bond and nature of the photocatalyst from the FTIR results proved that the synthesis process to produce the ZnO/KCC-1 was succeed. The large surface area of KCC-1 increases the effectiveness of ZnO which is supported by the experimental data. Accordingly, the optimum condition for photocatalytic degradation of thiophene is under pH 7 by using ZnO/KCC-1 as photocatalyst. Hence, it is believed that this research could be implemented to remove the thiophene in petroleum fraction from the actual industrial effluents and this can preserve nature in the future.

scholarly journals Investigation of the β-pinene photooxidation by OH in the atmosphere simulation chamber SAPHIR

2016 ◽  
Author(s):  
Martin Kaminski ◽  
Hendrik Fuchs ◽  
Ismail-Hakki Acir ◽  
Birger Bohn ◽  
Theo Brauers ◽  
...  
Keyword(s):  
Degradation Mechanism ◽  
Degradation Process ◽  
Product Distribution ◽  
High Reactivity ◽  
Oxidation Products ◽  
Chemical Mechanism ◽  
Emission Rates ◽  
Photochemical Degradation ◽  
Atmosphere Simulation Chamber ◽  
Simulation Chamber

Abstract. Beside isoprene, monoterpenes are the non-methane volatile organic compounds (VOC) with the highest global emission rates. Due to their high reactivity towards OH, monoterpenes can dominate the radical chemistry of the atmosphere in forested areas. In the present study the photochemical degradation mechanism of β-pinene was investigated in the Jülich atmosphere simulation chamber SAPHIR. The focus of this study is on the OH budget in the degradation process. Therefore the SAPHIR chamber was equipped with instrumentation to measure radicals (OH, HO2, RO2), the total OH reactivity, important OH precursors (O3, HONO, HCHO), the parent VOC beta-pinene, its main oxidation products, acetone and nopinone, and photolysis frequencies. All experiments were carried out under low NOx conditions (≤ 2 ppb) and at atmospheric beta-pinene concentrations (≤ 5 ppb) with and without addition of ozone. For the investigation of the OH budget, the OH production and destruction rates were calculated from measured quantities. Within the limits of accuracy of the instruments, the OH budget was balanced in all β-pinene oxidation experiments. However, even though the OH budget was closed, simulation results from the Master Chemical Mechanism 3.2 showed that the OH production and destruction rates were underestimated by the model. The measured OH and HO2 concentrations were underestimated by up to a factor of two whereas the total OH reactivity was slightly overestimated because of the poor reproduction of the measured nopinone by the model by up to a factor of three. A new, theory-derived first-generation product distribution by Vereecken and Peeters was able to reproduce the measured nopinone time series and the total OH reactivity. Nevertheless the measured OH and HO2 concentrations remained underestimated by the numerical simulations. These observations together with the fact that the measured OH budget was closed suggest the existence of unaccounted sources of HO2.

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