order reaction
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2021 ◽  
pp. 1-15
Author(s):  
Nian Cheng ◽  
Jingyi Huang ◽  
Yingru Wang

It is of great significance to study the treatment of organic dye pollution. In this work, a method of electrochemical treatment for reactive blue 19 dye (RB19) wastewater system was established, and it was applied to the actual dye wastewater treatment. The effects of applied voltage, electrolyte concentration, electrode spacing, and initial concentration on the removal effect of RB19 have been studied in detail. The results show that the removal rate of RB19 can reach 82.6% and the chemical oxygen demand (CODcr) removal rate is 54.3% under optimal conditions. The removal of RB19 in the system is mainly the oxidation of hydroxyl free radicals. The possible degradation pathway is inferred by ion chromatography: hydroxyl free radicals attack the chromophoric group of RB19 to make it fall off, and then decompose it into ring-opening. The product is finally oxidized to CO2 and water. The kinetic fitting is in accordance with the zero-order reaction kinetics. At the same time, using the established electrochemical system to treat the actual dye wastewater has also achieved good results. After 3 hours of treatment, the CODcr removal rate of the raw water is 44.8%, and the CODcr removal of the effluent can reach 89.5%. The degradation process conforms to the zero-order reaction kinetics. The result is consistent with the electrochemical treatment of RB19.


2021 ◽  
Vol 11 (4) ◽  
pp. 142-154
Author(s):  
Arnab Goon ◽  
Arijita Bhattacharyya ◽  
Bappa Ghosh ◽  
Rajiv Rakshit ◽  
Anupam Das ◽  
...  

Photodegradation (photolysis) causes the breakdown of organic pesticides molecules by direct or indirect solar radiation energy. Flucetosulfuron herbicide often encounters water bodies. For this reason, it is important to know the behavior of the compound under these stressed conditions. In this context, photodegradation of flucetosulfuron, a sulfonylurea-based herbicide, has been assessed in aqueous media in the presence of photocatalyst TiO2 and photosensitizers (i.e., H2O2, humic acid, and KNO3) under the influence of ultraviolet (UV) irradiation. The influence of different water systems was also assessed during the photodegradation study. The photodegradation followed the first-order reaction kinetics in each case. The metabolites after photolysis were isolated in pure form by column chromatographic method and characterized using the different spectral data (i.e., XRD, IR, NMR, UV-VIS, and mass spectrometry). The structures of these metabolites were identified based on the spectral data and the plausible photodegradation pathways of flucetosulfuron were suggested. Based on the findings, photocatalyst TiO2 with the presence of ultraviolet irradiation was found effective for the photodegradation of toxic flucetosulfuron residues under aqueous conditions.


Author(s):  
Magdalena Pappenreiter ◽  
Gabriele Lhota ◽  
Karola Vorauer-Uhl ◽  
Bernhard Sissolak

Glycation on lysine side chains of recombinant monoclonal antibodies (mAb) is a well known phenomenon in manufacturing processes of biopharmaceuticals that potentially alter the efficacy of the therapeutic protein. Previously, we reported a method to quantify the level of glycation formation directly from cell culture supernatants using boronate affinity chromatography (BAC). In this study, we report kinetic studies of glycation formation of the model protein Adalimumab, related to glucose and non-glycated protein in six CHO fed batch cultivations. An in-vivo model was demonstrated from glycation kinetic studies that is capable of estimating the reaction rate constant in static and dynamic bioprocesses, respectively. As anticipated, pseudo first order reactions with respect to present glucose concentration or non-glycated mAb were not sufficient to describe the glycation formation during the bioprocesses. However, second order reactions did not reveal linear relationship of glycated mAb to the product of glucose and non-glycated mAb, suggesting a reconsideration of kinetic equation. With the introduction of a constraint using only the newly formed product, i.e., the nascent protein, the second-order reaction was successfully implemented. These results show that the process knowledge derived from dynamic can be transferred to static experiments and vice versa. Hence, intensified DoE can be an applicable and useful tool in product quality studies in cell culture processes.


Author(s):  
Amel S. Mahdi ◽  
Barakat A. F. Kamel ◽  
Athraa S. Ahmed ◽  
Kafi M. Dawood

In this work the photo degradation of glibinclamide is studied by UV light and different concentrations using solvents (water and ethanol) and different times. The reaction kinetic is studied and found that the photo degradation reaction of glibinclamide is (first-order) reaction and the thermodynamic properties (ΔHo, ΔSo and ΔGo) for glibinclamide were calculated and it was found to be (endothermic and spontaneous reaction).


Fractals ◽  
2021 ◽  
pp. 2240020
Author(s):  
MOHAMED ADEL ◽  
MOHAMED ELSAID

Anomalous Reaction-Sub-diffusion equations play an important role transferred in a lot of our daily applications in our life, especially in applied chemistry. In the presented work, a modified type of these models is considered which is the Reaction-Sub-diffusion equation of variable order, the linear and nonlinear models and we will refer to it by VORSDE. An accurate technique depends on a mix of the finite difference methods (FDM) together with Hermite formula is introduced to study these important types of anomalous equations. Regarding the analysis of the stability for the mentioned, it is done using the variable Von-Neumann technique; also the convergent analysis is introduced. As a result of the previous steps, we derived a stability condition which will be held for many discretization schemes of the variable order derivative and some other parameters and we checked it numerically.


Author(s):  
Juhaina Alghdir ◽  
Ahmad Falah ◽  
Sameh Hamo

This study includes the preparation of the polyaniline at the laboratory temperature in an acidic medium. The Scanning Electron Microscopy (SEM) analysis of Polyaniline shows smooth surface and uniform nanoparticles formation with diameters of 56.4 to 90 nm. The polymerization of polyaniline kinetics was studied with two methods: UV-Vis, HPLC. Then the polymerization of polyaniline reaction order was determined and it was the zero-order reaction (n=0) in both of the previous two methods. The study of thermal dissociation indicates the temporal stability of chemicals, and study the decomposition kinetics to determine the thermodynamic functions of material disintegration. There are many methods use mathematical equations applied to TGA to study this phenomenon. The thermodynamic functions of the prepared polymers such as (G*, S*, H*) were determined based on Coats-Redfern equation from TGA curves of the compounds at each step of the disintegration.


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