scholarly journals Photocatalytic oxidation of psychoactive drug Duloxetine: Degradation kinetics, inorganic ions and phytotoxicity evaluation

2020 ◽  
Vol 3 (1) ◽  
pp. 31
Author(s):  
Sophia Tsoumachidou ◽  
Maria Valari ◽  
Ioannis Poulios
Keyword(s):  
Photocatalytic Oxidation ◽  
Degradation Kinetics ◽  
Inorganic Ions ◽  
Reaction Rates ◽  
Psychoactive Drug ◽  
Public Health Issue ◽  
Initial Reaction ◽  
Pharmaceutically Active Compounds ◽  
Contaminate Drinking Water ◽  
Made In

Pharmaceutically active compounds, emerging extensively in ecosystems as pollutants, have become an important environmental and public health issue, since they can contaminate drinking water and pose threat to wildlife and human health. Therefore, efforts should be made in order to establish proper methods for their inactivation or elimination in the environment. The photocatalytic oxidation of psychoactive drug Duloxetine (DLX) has been investigated. In the case of heterogeneous photocatalytic oxidation, the effect of TiO2 P25 concentration (0.1–1 g L-1), initial concentration of H2O2 (0.25–0.2 g L-1) and Fe3+ (0.00175–0.014 g L-1) and pH of the solution (3–10) on initial reaction rates were evaluated, while for homogeneous photocatalytic oxidation the effect of the amount of H2O2 (0.25–0.2 g L-1) and Fe3+ (0.00175–0.014 g L-1) were investigated. Additionally, the conversion of the heteroatoms in the molecule of DLX to inorganic ions (NO3-, NH4+, SO42-) during photocatalytic process has been observed, and phytotoxicity testing, using three plant species, was carried out in order to examine the effect of photocatalytic oxidation on the toxicity of DLX. According to the results presented in this study, both heterogeneous and homogeneous photocatalytic oxidation is an efficient methodology for DLX degradation.

scholarly journals Sonochemical and Sonoelectrochemical Production of Energy Materials

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 284
Author(s):  
Faranak Foroughi ◽  
Jacob J. Lamb ◽  
Odne S. Burheim ◽  
Bruno G. Pollet
Keyword(s):  
Reaction Rates ◽  
Surface Cleaning ◽  
Energy Materials ◽  
Fast Reaction ◽  
Ultrasound Frequency ◽  
Production Of Hydrogen ◽  
Scientists And Engineers ◽  
Electrocatalyst Materials ◽  
Made In ◽  
Semiconductor Photocatalyst

Sonoelectrochemistry is the combination of ultrasound and electrochemistry which provides many advantages in electrochemistry, such as fast reaction rates, surface cleaning and activation, and increased mass transport at an electrode. Due to the advantages, some efforts have been made in order to benefit sonoelectrochemistry in the field of energy and environmental engineering. This review paper highlights the developed progress of the application of sonoelectrochemistry in the production of hydrogen, electrocatalyst materials and electrodes for fuel cells and semiconductor photocatalyst materials. This review also provides the experimental methods that are utilized in several sonoelectrochemical techniques, such as different set-ups generally used for the synthesis of energy-related materials. Different key parameters in the operation of sonoelectrochemical synthesis including ultrasonication time, ultrasound frequency and operation current have been also discussed. There are not many research articles on the sonoelectrochemical production of materials for supercapacitors and water electrolyzers which play crucial roles in the renewable energy industry. Therefore, at the end of this review, some articles which have reported the use of ultrasound for the production of electrocatalysts for supercapacitors and electrolyzers have been reviewed. The current review might be helpful for scientists and engineers who are interested in and working on sonoelectrochemistry and electrocatalyst synthesis for energy storage and energy conversion.

Ensemble Learning Approach with LASSO for Predicting Catalytic Reaction Rates

Synlett ◽  
2020 ◽  
Author(s):  
Akira Yada ◽  
Kazuhiko Sato ◽  
Tarojiro Matsumura ◽  
Yasunobu Ando ◽  
Kenji Nagata ◽  
...  
Keyword(s):  
Ensemble Learning ◽  
Reaction Rates ◽  
Initial Reaction Rate ◽  
Training Dataset ◽  
Initial Reaction ◽  
Learning Approach ◽  
Learning Framework ◽  
Machine Learning Approach ◽  
Reasonable Prediction ◽  
Epoxidation Of Alkenes

AbstractThe prediction of the initial reaction rate in the tungsten-catalyzed epoxidation of alkenes by using a machine learning approach is demonstrated. The ensemble learning framework used in this study consists of random sampling with replacement from the training dataset, the construction of several predictive models (weak learners), and the combination of their outputs. This approach enables us to obtain a reasonable prediction model that avoids the problem of overfitting, even when analyzing a small dataset.

scholarly journals Uptake of Zn, Pb, Cu and Fe Ions from Spent and Unspent Engine Oil Using Termite Soil

2017 ◽  
Vol 9 (3) ◽  
pp. 85
Author(s):  
Iwekumo Agbozu ◽  
Bassey Uwem ◽  
Boisa Ndokiari
Keyword(s):  
Contact Time ◽  
Diffusion Constant ◽  
Reaction Rates ◽  
Second Order ◽  
Engine Oil ◽  
Initial Reaction ◽  
Kinetics Equation ◽  
Spent Engine Oil ◽  
Pseudo Second Order ◽  
Fe Ions

Removal of Zn, Pb, Cu and Fe ions from unspent and spent engine oil was studied using Termite soil. Process parameters such as contact time and adsorbent dosage were varied. Values from contact time were used for predicting kinetics equation of their uptake. At optimum time of 40 minutes, percentage adsorption was of the order Fe>Zn>Cu>Pb for both spent and unspent engine oil. Kinetics equation such as Elovich, Intra-particle, Pseudo-first order and Pseudo-second order were tested. Results obtained shows that their sequestering pattern fit into the pseudo-second order kinetics. Initial reaction rates, h (mg/g.min) and α (mg. g-1min-1) for all metal ions obtained from Pseudo-second order and Elovich kinetic models followed the trends Zn>Fe>Cu>Pb and Zn>Fe>Pb>Cu respectively in spent engine oil while for unspent engine oil, the trend was Fe>Zn>Cu>Pb for h (mg/g.min) and Zn>Fe>Pb>Cu for α (mg. g-1min-1). Electrostatic attraction existing on the surface of the adsorbent assisted in the high initial reaction of Zn and Fe ions, implying good affinity of the ions for the adsorbent. Desorption constant ᵦ (g/mg) was of the trend Cu>Pb>Fe>Zn and Cu>Pb>Zn>Fe for spent and unspent engine oils respectively. Intra-particle diffusion constant kid (mgg-1min-1/2) followed a similar pattern, revealing strong binding between Zn and termite soil than any of the metal ion. This pilot research has been able to suggest a kinetic process for uptake of the studied ions from spent and unspent engine oil.

scholarly journals Studies on Epoxidation of Tung oil with Hydrogen Peroxide Catalyzed by Sulfuric Acid

2020 ◽  
Vol 15 (3) ◽  
pp. 674-686
Author(s):  
Eni Budiyati ◽  
Rochmadi Rochmadi ◽  
Arief Budiman ◽  
Budhijanto Budhijanto
Keyword(s):  
Hydrogen Peroxide ◽  
Sulfuric Acid ◽  
Unsaturated Fatty Acids ◽  
Catalyst Concentration ◽  
Reaction Rates ◽  
Catalytic Reactions ◽  
Side Reactions ◽  
Initial Reaction ◽  
Tung Oil ◽  
Epoxidation Reaction

Tung oil with an iodine value (IV) of 99.63 g I2/100 g was epoxidized in-situ with glacial acetic acid and hydrogen peroxide (H2O2), in the presence sulfuric acid as catalyst. The objective of this research was to evaluate the effect of mole ratio of H2O2 to unsaturated fatty acids (UFA), reaction time and catalyst concentration in Tung oil epoxidation. The reaction kinetics were also studied. Epoxidation was carried out for 4 h. The reaction rates and side reactions were evaluated based on the IV and the conversion of the epoxidized Tung oil to oxirane. Catalytic reactions resulted in higher reaction rate than did non-catalytic reactions. Increasing the catalyst concentration resulted in a large decrease in the IV and an increase in the conversion to oxirane at the initial reaction stage. However, higher catalyst concentration in the epoxidation reaction caused to a decrease in reaction selectivity. The mole ratio of H2O2 to UFA had an influence identical to the catalyst concentration. The recommended optimum mole ratio and catalyst concentration in this study were 1.6 and 1.5%, respectively. The highest conversion was 48.94% for a mole ratio of 1.6. The proposed kinetic model provided good results and was suitable for all variations in reaction temperature. The activation energy (Ea) values were around 5.7663 to 76.2442 kcal/mol. Copyright © 2020 BCREC Group. All rights reserved 

Photocatalytic Treatment of Wastewater From 5–Fluorouracil Manufacturing

1996 ◽  
Vol 118 (1) ◽  
pp. 2-8 ◽  
Author(s):  
M. Anheden ◽  
D. Y. Goswami ◽  
G. Svedberg
Keyword(s):  
Hydrogen Peroxide ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Substantial Reduction ◽  
Reduction Rate ◽  
Reaction Rates ◽  
Batch Experiments ◽  
Cod Reduction ◽  
Potential Use ◽  
Percent Decrease

This paper presents some of the experimental results from a study conducted to demonstrate the potential use of photocatalytic oxidation for decolorization and COD reduction of wastewater from 5–fluorouracil manufacturing. A series of batch experiments, were carried out using diluted solutions of the wastewater with 0.1 percent w/v TiO2. Low pressure mercury lamps were used to simulate the UV part of sunlight. The experiments showed that a complete decolorization and a substantial reduction of COD was achieved within 20 hours with a 20 percent solution. During the reaction period, the pH was noted to decrease considerably, indicating formation of acids. Adding hydrogen peroxide to the solution was found to significantly increase the reaction rates. Adding 2400 ppm of H2O2 gave an 80 percent decrease in color in one hour and a 70-80 percent decrease in COD in 20 hours. The influence of UV-light intensity was also examined. This experiment showed that with a UV-intensity of 15 W/m2, i.e., a cloudy day, the decolorization rate was still considerable, while the COD reduction rate was very low.

scholarly journals Enhanced Catalytic Dye Decolorization by Microencapsulation of Laccase from P. Sanguineus CS43 in Natural and Synthetic Polymers

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1353
Author(s):  
Natalia Lopez-Barbosa ◽  
Ana Lucía Campaña ◽  
Juan C. Cruz ◽  
Nancy Ornelas-Soto ◽  
Johann F. Osma
Keyword(s):  
Catalytic Activity ◽  
Confocal Microscopy ◽  
Fluorescent Dyes ◽  
Fold Increase ◽  
Dye Decolorization ◽  
Reaction Rates ◽  
Lower Amount ◽  
Poly Vinyl Alcohol ◽  
Initial Reaction ◽  
Pycnoporus Sanguineus

Polymeric microcapsules with the fungal laccase from Pycnoporus sanguineus CS43 may represent an attractive avenue for the removal or degradation of dyes from wastewaters. Microcapsules of alginate/chitosan (9.23 ± 0.12 µm) and poly(styrenesulfonate) (PSS) (9.25 ± 0.35 µm) were synthesized and subsequently tested for catalytic activity in the decolorization of the diazo dye Congo Red. Successful encapsulation into the materials was verified via confocal microscopy of labeled enzyme molecules. Laccase activity was measured as a function of time and the initial reaction rates were recovered for each preparation, showing up to sevenfold increase with respect to free laccase. The ability of substrates to diffuse through the pores of the microcapsules was evaluated with the aid of fluorescent dyes and confocal microscopy. pH and thermal stability were also measured for encapsulates, showing catalytic activity for pH values as low as 4 and temperatures of about 80 °C. Scanning electron microscope (SEM) analyses demonstrated the ability of PSS capsules to avoid accumulation of byproducts and, therefore, superior catalytic performance. This was corroborated by the direct observation of substrates diffusing in and out of the materials. Compared with our PSS preparation, alginate/chitosan microcapsules studied by others degrade 2.6 times more dye, albeit with a 135-fold increase in units of enzyme per mg of dye. Similarly, poly(vinyl) alcohol microcapsules from degrade 1.7 times more dye, despite an eightfold increase in units of enzyme per mg of dye. This could be potentially beneficial from the economic viewpoint as a significantly lower amount of enzyme might be needed for the same decolorization level achieved with similar encapsulated systems.

Photocatalytic oxidation of methyl ethyl ketone over sol-gel and commercial TiO2 for the improvement of indoor air

2006 ◽  
Vol 53 (11) ◽  
pp. 107-115 ◽  
Author(s):  
C. Raillard ◽  
V. Héquet ◽  
P. Le Cloirec ◽  
J. Legrand
Keyword(s):  
Methyl Ethyl Ketone ◽  
Indoor Air ◽  
Photocatalytic Oxidation ◽  
Degradation Kinetics ◽  
Sol Gel ◽  
Degradation Pathway ◽  
Air Pollutant ◽  
Methyl Ethyl ◽  
Fixed Temperature ◽  
Glass Plates

This work focuses on the photocatalytic oxidation of gaseous methyl ethyl ketone chosen as a typical indoor air pollutant. Two types of TiO2 coatings were prepared and deposited on glass plates: one using the commercial Degussa P25 TiO2 and the other one by sol-gel method. The first objective of this study was to compare different ways of preparing thin films of sol-gel TiO2 coated on glass plates, taking into account their general aspect and their photocatalytic efficiency. Several parameters were tested, such as the stabilising agent, the glass type of the support, the number of coatings and the calcination temperature. One of the synthesised materials was then kept to carry out the following study. The study aimed to assess the influence of TiO2 coating types on the effect of water vapour. This was achieved by performing MEK photocatalytic degradation kinetics under two levels of humidity at a fixed temperature. Experimental results were then modelled by the Langmuir-Hinshelwood equation. The obtained parameters gave specific trends in function of the considered catalyst. The second part of this work was to identify MEK degradation byproducts during its photocatalytic oxidation. The main detected intermediate was acetaldehyde, followed by methyl formate. A MEK degradation pathway was then proposed.

scholarly journals Layer-Like Zeolite X as Catalyst in a Knoevenagel Condensation: The Effect of Different Preparation Pathways and Cation Exchange

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 474
Author(s):  
Jan-Paul Grass ◽  
Katharina Klühspies ◽  
Bastian Reiprich ◽  
Wilhelm Schwieger ◽  
Alexandra Inayat
Keyword(s):  
Catalytic Activity ◽  
Reaction Rate ◽  
Knoevenagel Condensation ◽  
Ethyl Cyanoacetate ◽  
Reaction Rates ◽  
Initial Reaction Rate ◽  
Comparative Investigation ◽  
Morphological Properties ◽  
Initial Reaction ◽  
Zeolite X

This study is dedicated to the comparative investigation of the catalytic activity of layer-like Faujasite-type (FAU) zeolite X obtained from three different synthesis routes (additive-free route, Li2CO3 route, and TPOAC route) in a liquid-phase Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate to ethyl trans-α-cyanocinnamate. It is shown that the charge-balancing cations (Na+ and K+) and the morphological properties have a strong influence on the apparent reaction rate and degree of conversion. The highest initial reaction rate could be found for the layer-like zeolite X synthesised by the additive-free route in the potassium form. In most cases, the potassium-exchanged zeolites enabled higher maximum conversions and higher reaction rates compared to the zeolite X catalysts in sodium form. However, very thin crystal plates (below 100 nm thickness), similar to those obtained in the presence of TPOAC, did not withstand the multiple aqueous ion exchange procedure, with the remaining coarse crystals facilitating less enhancement of the catalytic activity.

Surface-Active Ionic Liquids in Catalytic Water Splitting

2019 ◽  
Vol 72 (2) ◽  
pp. 34 ◽  
Author(s):  
Alice Cognigni ◽  
Ádám Márk Palvögyi ◽  
Christian Schröder ◽  
Herwig Peterlik ◽  
Alexander R. M. Müllner ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Water Splitting ◽  
External Surface ◽  
Reaction Rates ◽  
Initial Reaction ◽  
Surface Active Ionic Liquid ◽  
Surface Active ◽  
Turn Over ◽  
Catalytic Cycles ◽  
Reaction Media

We report the application of surface-active ionic liquids as ligands and optional reaction media in iridium-catalyzed water oxidations. Three novel catalysts with N,N-dialkylimidazolidin-2-ylidene ligands based on amphiphilic imidazolium ionic liquids were synthesized and characterized. Excellent turn-over frequencies of up to 0.92s−1 were obtained in catalytic water splitting, and activity was maintained for five consecutive catalytic cycles, with an overall turn-over number of 8967. The addition of external surface-active ionic liquid showed unexpected behaviour, because strongly enhanced initial reaction rates were observed.

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