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

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.

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

Catalysts ◽

10.3390/catal11040474 ◽

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.

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Assessing the Activity of Lewis Bases Organocatalysts in Halonium-Induced Carbocyclization Reactions

Synlett ◽

10.1055/s-0036-1591982 ◽

2018 ◽

Vol 29 (09) ◽

pp. 1181-1186 ◽

Cited By ~ 1

Author(s):

Charlotte Grandclaudon ◽

Mirko Ruamps ◽

Raphaël Duboc ◽

Véronique Michelet ◽

Patrick Toullec

Keyword(s):

Catalytic Activity ◽

High Activity ◽

Reaction Rate ◽

Fold Increase ◽

Initial Reaction Rate ◽

Initial Reaction ◽

Lewis Bases ◽

Background Reaction

Lewis bases were evaluated as catalysts for halocarbocyclization reactions of alkynylstyrenes and a cinnamylaniline derivative. Phosphines and phosphorus chalcogenides exhibited high activity for the conversion of alkynylstyrenes in the presence of N-halosuccinimides with up to a 30-fold increase of the initial reaction rate with respect to the background reaction. Phosphorus sulfides and selenides showed the best catalytic activity for the iodocarbocyclization of a cinnamylaniline derivative in the presence of diiodohydantoin. An asymmetric variant of the iodocarbocyclization reaction of an alkynylstyrene using a chiral phosphorus selenide resulted in a modest enantioselectivity.

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The effect of the content of sulphonic acid groups of an ion exchanger upon its catalytic activity

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19790502 ◽

1979 ◽

Vol 44 (2) ◽

pp. 502-507 ◽

Cited By ~ 4

Author(s):

Karel Setínek

Keyword(s):

Surface Layer ◽

Catalytic Activity ◽

Liquid Phase ◽

Alkali Metal ◽

Reaction Rates ◽

Sulphonic Acid ◽

Ion Exchanger ◽

Alkali Metal Ions ◽

Initial Reaction ◽

Different Thickness

Measurements of the initial reaction rates of the gas and liquid phase reesterification of ethyl acetate by 1-propanol catalyzed by an acid ion exchanger showed that the gradual neutralization of the acid groups by alkali metal ions in aqueous medium decreases uniformly their concentration within the whole mass of the catalyst, which reflects in the gradual decrease in the catalytic activity. On varying the content of sulphonic acid groups by sulphonation of the starting copolymer to a different degree, the ion exchangers possessing fully sulphonated surface layer of different thickness are formed which exhibit the same catalytic activity. The decrease in the activity has been observed only after the sulphonation degree was less than 50 per cent.

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Ensemble Learning Approach with LASSO for Predicting Catalytic Reaction Rates

Synlett ◽

10.1055/a-1304-4878 ◽

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.

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Reduction in lignin peroxidase activity revealed by effects of lignin content in urea crosslinked starch under aerobic biodegradation in soil

BioResources ◽

10.15376/biores.16.1.1940-1948 ◽

2021 ◽

Vol 16 (1) ◽

pp. 1940-1948

Author(s):

Zahid Majeed ◽

Zainab Ajab ◽

Qingjie Guan ◽

Abdul Zahir Abbasi ◽

Qaisar Mahmood ◽

...

Keyword(s):

Catalytic Activity ◽

Lignin Peroxidase ◽

Enzyme Assay ◽

Lignin Content ◽

Complex Structure ◽

Reaction Rates ◽

Aerobic Biodegradation ◽

Lignin Biodegradation ◽

Research Findings ◽

Biodegradation In Soil

This study characterized the lignin peroxidase (LiP) activity of soil via an enzyme assay to determine the reaction rates and activation energies for 5 wt%, 10 wt%, 15 wt%, and 20 wt% lignin loads in urea crosslinked starch biocomposites. The results revealed that a mixed mode of LiP inhibition occurred after the soil was mixed with these biocomposites with different loads of lignin. Loading of lignin at 5 wt% and 10 wt% lignin resulted in higher values of catalytic activity of LiP: -39.58 and 49.14 µM h-1 g-1 soil, respectively. In comparison, with higher loading of lignin at 15 wt% and 20 wt%, decreases in the catalytic activity of LiP were found and were 28.72 to 37.25 µM h-1 g-1 soil, respectively. The activation energy of LiP increased approximately 1.11- to 1.22-fold when 15 and 20 wt% of lignin was loaded in biocomposites. Research findings established the possibility of unfavorable binding of the LiP to lignin with an increase in the load of lignin, possibly due to the complex structure of intact lignin and presence of inhibitory biodegradation products of lignin accumulates during lignin biodegradation in biocomposites. It was concluded that higher lignin contents (15 wt% and 20 wt%) were effective in reducing the activity of the soil LiP. Hence, higher lignin content possibly protects against losses of lignin, while acting as a filler in the formulation of biocomposites.

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Effect of Metal Nanoparticles on the Catalytic Activity of Pectin (poly vinyl alcohol-co-polyacrylamide) Nanocomposite Hydrogels

Journal of Inorganic and Organometallic Polymers and Materials ◽

10.1007/s10904-018-1003-8 ◽

2018 ◽

Vol 29 (2) ◽

pp. 332-339 ◽

Cited By ~ 7

Author(s):

Faten Ismail Abou El Fadl ◽

Ghada Adel Mahmoud ◽

Areeg Ahmed Mohamed

Keyword(s):

Catalytic Activity ◽

Metal Nanoparticles ◽

Vinyl Alcohol ◽

Poly Vinyl Alcohol ◽

Nanocomposite Hydrogels

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

International Journal of Chemistry ◽

10.5539/ijc.v9n3p85 ◽

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.

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Radiation-Induced Synthesis of Copper/Poly(vinyl alcohol) Nanocomposites and Their Catalytic Activity

Advances in Polymer Technology ◽

10.1002/adv.21675 ◽

2016 ◽

Vol 37 (2) ◽

pp. 365-375 ◽

Cited By ~ 7

Author(s):

Z. I. Ali ◽

O. A. Ghazy ◽

G. Meligi ◽

H. H. Saleh ◽

M. Bekhit

Keyword(s):

Catalytic Activity ◽

Vinyl Alcohol ◽

Poly Vinyl Alcohol ◽

Radiation Induced

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

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS ◽

10.9767/bcrec.15.3.8243.674-686 ◽

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

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