scholarly journals RETRACTED ARTICLE: Kinetic and anion degradation products study on photocatalytic degradation of reactive orange 5 solution with phosphotungstic acid

2008 ◽  
Vol 6 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Junbo Zhong ◽  
Hong Zhao ◽  
Di Ma ◽  
An Lian ◽  
Minjiao Li ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Photocatalytic Degradation ◽  
Phosphotungstic Acid ◽  
Degradation Products ◽  
Degradation Mechanism ◽  
Reaction System ◽  
Retracted Article ◽  
Degradation Reaction ◽  
The Difference ◽  
Reactive Orange

AbstractIncreasing environmental pollution caused by toxic dyes is a matter of great concern due to their hazardous nature. So it is crucial to develop processes which can destroy these dyes effectively. It has been generally agreed that reactive orange 5 (KGN) can be effectively degraded in aerated phosphotungstic acid (HPA) in a homogeneous reaction system using near-UV irradiation. In this paper, photocatalytic degradation of reactive orange 5 solutions with phosphotungstic acid was investigated, especially more attention was paid to the kinetic model and the anion degradation products. The results revealed that the photocatalytic degradation reaction of KGN with HPA in a homogenous solution can be described by Langmuir-Hinshelwood equation and Langmuir-Hinshewood kinetic model described it well. The reaction manifested the first order with lower concentration(⩽30 mg L−1) with the limiting rate constant and the adsorption constant in this case being 0.8098 mg L−1 min−1 and 4.359 10−2 L mg−1, respectively. The degradation mechanism of KGN with HPA is different from that with TiO2, the anion products of the two reaction systems are the same. The difference in degradation mechanism of KGN with HPA from that with TiO2 is caused by the nature of the photocatalyst.

scholarly journals Enhanced Photocatalytic Performance in Chromium(VI) Reduction and Dye Degradation using Sn3O4/SnS2 Nanocomposite and Mechanism Insight

2021 ◽  
Author(s):  
Gandharve Kumar ◽  
Rajkumar Dutta
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Dye Degradation ◽  
Degradation Products ◽  
Degradation Mechanism ◽  
Reaction Medium ◽  
Blue Dye ◽  
Ros Scavenging ◽  
Hydrothermal Route ◽  
Inorganic Species

Abstract Detection of residual organic and inorganic species in water bodies including drinking water has led to developing strategies for their removal. Here we report a very efficient method of photoreduction of Cr (VI) and photodegradation of methylene blue dye in aqueous medium using Z-scheme heterojunction based Sn3O4/SnS2 solar photocatalyst. The photocatalyst is synthesized by hydrothermal route and it is thoroughly characterized in terms of its structural, compositional, morphological and optical properties. About 100 % of Cr (VI) reduction in 60 min and 99.6 % of methylene blue degradation in 90 min is achieve under sunlight exposure at a photocatalytic rate of 0.066 min-1 and 0.043 min-1, respectively. The total organic carbon estimation of the post-degradation reaction medium corresponded to 85.1 % (MB) mineralization. The photocatalytic degradation is attributed to in-situ generation of reactive oxygen species (ROS) e.g., superoxide radicals, hydroxide radicals, and the role of ROS towards reduction and degradation of Cr (VI) and MB respectively, is confirmed from ROS scavenging studies. The dye degradation mechanism has been discussed by analyzing the degradation products via UPLC-Q-Tof-MS. The photocatalytic degradation of methylene blue by Sn3O4/SnS2 nanocomposites is significantly enhanced as compared to SnS2 photocatalyst, attributed to Z-scheme heterojunction and the charge carrier mobility.

RETRACTED: Kinetic study on photocatalytic degradation of reactive orange 5 solution with phosphotungstic acid

2008 ◽  
Vol 283 (1-2) ◽  
pp. 93-98 ◽  
Author(s):  
Zhong Junbo ◽  
Ma Di ◽  
Zhao Hong ◽  
Li Minjiao ◽  
Xie Bin ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Kinetic Study ◽  
Phosphotungstic Acid ◽  
Reactive Orange

Enhanced Visible-Light Photocatalytic Remediation of Tetracycline Hydrochloride by Nanostructured BiOI Homojunctions

NANO ◽  
2019 ◽  
Vol 14 (09) ◽  
pp. 1950112
Author(s):  
Mengzhu Qiao ◽  
Hongjin Liu ◽  
Jun Lv ◽  
Guangqing Xu ◽  
Xinyi Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Degradation Mechanism ◽  
Tetracycline Hydrochloride ◽  
Photodegradation Rate ◽  
Degradation Activity ◽  
Degradation Reaction ◽  
Photocatalytic Degradation Mechanism ◽  
Bioi Nanosheets ◽  
Photoinduced Charge

The BiOI homojunctions were constructed between BiOI nanosheets and BiOI nanoflowers, which were prepared with a facile ultrasound-assisted solvothermal method. BiOI nanosheets were uniformly distributed on BiOI nanoflowers surface. The homojunction structure constructed between nanosheets and nanoflowers efficiently speeds up the transfer and separation of photoinduced charge carriers, which is beneficial to promote the photocatalytic activity. Compared with single BiOI, BiOI homojunctions exhibit remarkably improved photocatalytic degradation activity for tetracycline hydrochloride (TC); photodegradation rate of 69.43% for TC has been reached after being irradiated under visible light for 1[Formula: see text]h. Deeper analyses of photocatalytic degradation mechanism of TC have been conducted; the results identify that [Formula: see text] and h[Formula: see text] play important roles during the TC degradation reaction.

scholarly journals Mechanism and Kinetic Analysis of Degradation of Atrazine by US/PMS

2019 ◽  
Vol 16 (10) ◽  
pp. 1781 ◽  
Author(s):  
Yixin Lu ◽  
Wenlai Xu ◽  
Haisong Nie ◽  
Ying Zhang ◽  
Na Deng ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Degradation Rate ◽  
Degradation Products ◽  
Degradation Kinetics ◽  
Degradation Mechanism ◽  
Reaction System ◽  
Mechanism Analysis ◽  
Product Analysis ◽  
Suppression Effect ◽  
Degradation Effect

The degradation effect, degradation mechanism, oxidation kinetics, and degradation products of Atrazine (ATZ) by Ultrasound/Peroxymonosulfate (US/PMS) in phosphate buffer (PB) under different conditions were studied. It turned out that the degradation rate of US/PMS to ATZ was 45.85% when the temperature of the reaction system, concentration of PMS, concentration of ATZ, ultrasonic intensity, and reaction time were 20 °C, 200 μmol/L, 1.25 μmol/L, 0.88 W/mL, and 60 min, respectively. Mechanism analysis showed that PB alone had no degradation effect on ATZ while PMS alone had extremely weak degradation effect on ATZ. HO• and SO4−• coexist in the US/PMS system, and the degradation of ATZ at pH7 is dominated by free radical degradation. Inorganic anion experiments revealed that Cl−, HCO3−, and NO3− showed inhibitory effects on the degradation of ATZ by US/PMS, with Cl− contributing the strongest inhibitory effect while NO3− showed the weakest suppression effect. According to the kinetic analysis, the degradation kinetics of ATZ by US/PMS was in line with the quasi-first-order reaction kinetics. ETA with concentration of 1 mmol/L reduced the degradation rate of ATZ by US/PMS to 10.91%. Product analysis indicated that the degradation of ATZ by US/PMS was mainly achieved by dealkylation, dichlorination, and hydroxylation, but the triazine ring was not degraded. A total of 10 kinds of ATZ degradation intermediates were found in this experiment.

scholarly journals Photocatalytic Degradation of 4,4′-Isopropylidenebis(2,6-Dibromophenol) on Sulfur-Doped Nano TiO2

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 361
Author(s):  
Joanna B. Kisała ◽  
Gerald Hörner ◽  
Adriana Barylyak ◽  
Dariusz Pogocki ◽  
Yaroslav Bobitski
Keyword(s):  
Photocatalytic Degradation ◽  
Degradation Mechanism ◽  
Degradation Efficiency ◽  
Compound I ◽  
Ion Release ◽  
Oxidation Reduction ◽  
Mixed Oxidation ◽  
Degradation Rates ◽  
Bromide Ion ◽  
Degradation Reaction

In present work, we examine the photocatalytic properties of S-doped TiO2 (S1, S2) compared to bare TiO2 (S0) in present work. The photocatalytic tests were performed in alkaline aqueous solutions (pH = 10) of three differently substituted phenols (phenol (I), 4,4′-isopropylidenebisphenol (II), and 4,4′-isopropylidenebis(2,6-dibromophenol) (III)). The activity of the catalysts was evaluated by monitoring I, II, III degradation in the reaction mixture. The physicochemical properties (particle size, ζ-potential, Ebg, Eu, E0cb, E0vb, σo, KL) of the catalysts were established, and we demonstrated their influence on degradation reaction kinetics. Substrate degradation rates are consistent with first-order kinetics. The apparent conversion constants of the tested compounds (kapp) in all cases reveal the sulfur-loaded catalyst S2 to show the best photocatalytic activity (for compound I and II S1 and S2 are similarly effective). The different efficiency of photocatalytic degradation I, II and III can be explained by the interactions between the catalyst and the substrate solution. The presence of bromine substituents in the benzene ring additionally allows reduction reactions. The yield of bromide ion release in the degradation reaction III corresponds to the Langmuir constant. The mixed oxidation-reduction degradation mechanism results in higher degradation efficiency. In general, the presence of sulfur atoms in the catalyst network improves the degradation efficiency, but too much sulfur is not desired for the reduction pathway.

Peritoneal Fluid and Plasma Fibrinolytic Activity in Women with Pelvic Inflammatory Disease

1992 ◽  
Vol 68 (02) ◽  
pp. 102-105 ◽  
Author(s):  
P J Dörr ◽  
E J P Brommer ◽  
G Dooijewaard ◽  
H M Vemer
Keyword(s):  
Pelvic Inflammatory Disease ◽  
Inflammatory Disease ◽  
Peritoneal Fluid ◽  
Fibrinolytic Activity ◽  
Degradation Products ◽  
Adhesion Formation ◽  
High Rate ◽  
Control Group ◽  
The Difference ◽  
Fibrinolytic Parameters

SummaryPrevious studies have shown that the fibrinolytic activity of peritoneum is depressed in local inflammation. We measured fibrinolytic parameters in peritoneal fluid and in plasma of 10 women with pelvic inflammatory disease (PID). Nine women, in whom laparoscopy for sterilisation was performed, served as a control group.In the peritoneal fluid of women with PID, PAI-Ag, t-PA-Ag and u-PA-Ag were many times higher than in the control group. In contrast to the antigens which may be present in inert complexes, the potentially active compounds, measured as t-PA activity and plasmin-activable scu-PA, were not significantly different in the two groups, and in none of the samples was the active enzyme tcu-PA detectable. Nevertheless, the mean peritoneal fluid TDP and FbDP concentrations were about twenty times higher in the PID group than in the control group. In plasma of PID patients, none of the parameters except u-PA-Ag differed from those in the control group. The difference between control and patient plasma u-PA-Ag was statistically significant, but too small to attach any relevance to the observation.Our data suggest that, in contrast to the classical concept of decreased fibrinolytic activity as a cause of adhesion formation, intraperitoneal fibrinolysis is enhanced in peritoneal inflammation through stimulation of the local production of t-PA and u-PA. Despite concomitant production of PAI, fibrinolysis occurs at a high rate, resulting in high levels of fibrin degradation products. Since this activated fibrinolysis does not meet the demand, therapeutic enhancement should be considered to prevent adhesions.

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.

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