scholarly journals Evaluation of Kinetic Pseudo-Order in the Photocatalytic Degradation of Ofloxacin

Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 24
Author(s):  
Giora Rytwo ◽  
Arye Lev Zelkind
Keyword(s):  
Half Life ◽  
Advanced Oxidation Processes ◽  
Degradation Kinetics ◽  
Simple Procedure ◽  
Life Time ◽  
Zero Order Kinetics ◽  
Low Concentrations ◽  
Antibiotic Drug ◽  
Kinetics Of ◽  
Additional Reduction

Ofloxacin is a highly efficient and widely used antibiotic drug. It is classified as a refractory pollutant due to its poor biodegradability. Consequently, it is commonly found in water sources, requiring efficient methods for its removal. Advanced oxidation processes (AOPs) offer efficient alternatives since those yield complete degradation not achieved in adsorption or membrane processes. Previous studies suggest ofloxacin degradation follows a pseudo-first or -second order processes, whereas for full removal of refractory pollutants—lower pseudo-orders are required. Monitoring the actual “pseudo-order” degradation kinetics of ofloxacin is needed to evaluate any proposed AOP process. This study presents a simple procedure to evaluate pseudo-orders of AOPs. Photolysis of 20 μM ofloxacin solutions follow pseudo-zero order kinetics, with half-life times (t1/2) of approx. 60 min. TiO2 heterogenous catalysts have been shown to have no influence at low concentrations (0.2 mg L−1), but a significant reduction of half-life time (t1/2 = 20 min) and increase in pseudo-order (0.8) is measured at 2.0 mg L−1. Similar results are obtained with homogenous catalysis by 2.0 mg L−1 H2O2. The combination of H2O2 and TiO2 catalysts shows additional reduction in half-time life with increase in the pseudo-order to 1.2. The conclusions are (1) heterogenous and homogenous photocatalysis can effectively degrade ofloxacin, (2) combined photocatalysis yields higher pseudo-order, being less prone to achieve full removal, and (3) analysis of specific pseudo-orders in AOPs of refractory pollutants helps to further elucidate the efficiency of the processes.

Evaluation of Kinetic Pseudo-Order in the Photocatalytic Degradation of Oflaxicin

2021 ◽  
Author(s):  
Giora Rytwo ◽  
Arye Lev Zelkind
Keyword(s):  
Half Life ◽  
Advanced Oxidation Processes ◽  
Degradation Kinetics ◽  
Simple Procedure ◽  
Life Time ◽  
Zero Order Kinetics ◽  
Antibiotic Drug ◽  
Heterogenous Catalyst ◽  
Kinetics Of ◽  
Additional Reduction

Ofloxacin is a highly efficient and widely used antibiotic drug. It is classified as a refractory pollutant due to its poor biodegradability. Consequently, it is commonly found in water sources, requiring efficient methods for its removal. Advanced Oxidation Processes (AOPs) offer efficient alternatives since those yield complete degradation not achieved in adsorption or membrane processes. Previous studies suggest ofloxacin degradation follows a pseudo-first or -second order processes, whereas for full removal of refractory pollutants – lower pseudo-orders are required. Monitoring the actual “pseudo-order” degradation kinetics of ofloxacin is needed to evaluate any proposed AOP process. This study presents a simple procedure to evaluate pseudo-orders of AOPs. Photolysis of 20 mM ofloxacin solutions follow pseudo-zero order kinetics, with half-life times (t1/2) of approx. 60 min. TiO2 heterogenous catalyst show to have no influence at low concentration (0.2 mg L-1) but a significant reduction of half-life time (t1/2 = 20 min) and increase in pseudo-order (0.8) is measured at 2.0 mg L-1. Similar results are obtained with homogenous catalysis by 2.0 mg L-1 H2O2. The combination of H2O2 and TiO2 catalysts shows additional reduction in half-time life with increase in the pseudo-order to 1.2. The conclusions are (1) heterogenous and homogenous photocatalysis can effectively degrade ofloxacin, (2) combined photocatalysis yields higher pseudo-order, being less prone to achieve full removal, (3) analysis of specific pseudo-orders in AOPs of refractory pollutants helps to further elucidate the efficiency of the processes.

scholarly journals Evaluation of Kinetic Pseudo-Order in the Photocatalytic Degradation of Oflaxicin

2021 ◽  
Author(s):  
Giora Rytwo ◽  
Arye Lev Zelkind
Keyword(s):  
Heterogeneous Catalysis ◽  
Half Life ◽  
Advanced Oxidation Processes ◽  
Simple Procedure ◽  
Life Time ◽  
Degradation Process ◽  
Zero Order ◽  
Oxidation Processes ◽  
Kinetics Of Degradation ◽  
Kinetics Of

Ofloxacin is an extensively used efficient antibiotic. However, since it is a refractory pollutant, it is found in water sources, requiring methods to remove it from the environment. Advanced Oxidation Processes (AOPs) offer efficient alternatives since it yields complete degradation not achieved in adsorption or membrane processes. Kinetics of degradation process require monitoring the "pseu-do-order" of it to deliver evaluation of the proposed AOPs. Most studies assume ofloxacin degra-dation follows pseudo-first or -second order processes, whereas for full removal of refractory pol-lutants – lower pseudo-orders are required. This study presents a simple procedure to evaluate pseudo-orders of AOPs. Photolysis of 20 M ofloxacin follows pseudo-zero order, with half-life time (t1/2) of ~ 60 min. Very low TiO2 concentration in heterogeneous catalysis (0.2 mg L-1) has no in-fluence but increasing catalyst to 2.0 mg L-1 reduces t1/2 to 20 min, increasing pseudo-order to 0.8. Similar results are obtained with 2.0 mg L-1 H2O2 homogenous catalysis. Combining H2O2 with TiO2 reduces t1/2, but pseudo-order increases further (1.2). The conclusions are (1) ofloxacin can be ef-fectively degraded by both heterogenous and homogenous photocatalysis, (2) combined photoca-talysis yields higher pseudo-order, being less prone to achieve full removal, (3) analysis of specific pseudo-order in AOPs of refractory pollutants helps to further elucidate the efficiency of the process presented.

scholarly journals Degradation kinetics of six sulfonamides in hen eggs under simulated cooking temperatures

2011 ◽  
Vol 76 (8) ◽  
pp. 1093-1101 ◽  
Author(s):  
Xin-Huai Zhao ◽  
Peng Wu ◽  
Ying-Hua Zhang
Keyword(s):  
Rate Constants ◽  
Half Life ◽  
Heating Temperature ◽  
Degradation Kinetics ◽  
Life Time ◽  
Hplc Method ◽  
First Order ◽  
Order Rate ◽  
Apparent Activation Energies ◽  
Kinetics Of

Six sulfonamides, i.e., sulfadiazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfamethoxazole and sulfamonomethoxine, were applied to spike whole hen eggs at 0.1 mg kg- 1 eggs. The spiked hen eggs were heated at 80 and 100 ?C to investigate the degradation kinetics of the sulfonamides under simulated cooking conditions. The sulfonamides added were extracted twice from the spiked eggs with dichloromethane by an ultrasonic-assistant extraction, and analyzed by a HPLC method after purification. The first-order rate constants and half-life times of the sulfonamides were calculated, and the corresponding apparent activation energy of their degradation was also obtained by application of the Arrhenius equation. The results indicated that all six sulfonamides degraded faster at the higher heating temperature, with first-order rate constants ranging from 0.0056 to 0.0108 min-1 at 80 ?C and from 0.0147 to 0.0394 min-1 at 100 ?C. The apparent activation energies for the degradation of the sulfonamides were estimated to be in the range 30.9 to 77.5 kJ mol-1. Sulfadiazine and sulfadimethoxine had the shortest and longest half-life time, respectively, and were the most instable and stable.

scholarly journals Dimethoate degradation in plants and during processing of yerba maté leaves

2002 ◽  
Vol 45 (4) ◽  
pp. 419-422 ◽  
Author(s):  
Miguel E. Schmalko ◽  
Laura A. Ramallo ◽  
Darío Ferreira ◽  
Rubén D. Berlingheri
Keyword(s):  
Gas Chromatography ◽  
Half Life ◽  
Degradation Kinetics ◽  
Life Time ◽  
Ilex Paraguariensis ◽  
Yerba Mate ◽  
Initial Value ◽  
Mass Selective Detector ◽  
Selective Detector ◽  
Kinetics Of

The objective of this research was to study degradation kinetics of dimethoate in plants of Ilex paraguariensis Saint Hilaire (or yerba maté) and during its processing. To determine dimethoate concentration, a capillary gas chromatography technique with a mass selective detector was used. Half-life times in plants ranked between 9.8 and 11.8 days. During processing, with a blanching and two drying steps, dimethoate concentration decayed to a 22.7% of its initial value (in dry basis); while during seasoning step (at 45°C), half-life time was 17.3 days. With these values, preharvest safety interval was determined.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

scholarly journals Degradation Kinetics of Anthocyanins in Shalgam Beverage

2019 ◽  
Vol 7 (2) ◽  
pp. 282
Author(s):  
Adnan Bozdoğan ◽  
Kurban Yaşar
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Half Life ◽  
Degradation Kinetics ◽  
Production Method ◽  
Order Reaction ◽  
Different Temperatures ◽  
Traditional Production ◽  
Effects Of Temperature ◽  
Kinetics Of

This research was performed to elucidate the effects of temperature on the degradation kinetics of anthocyanins in shalgam beverage. Shalgam beverage was produced according to traditional production method. Then, it was kept at three different temperatures (65°C, 75°C, and 85°C) for 12 hours, and the relevant quantities of anthocyanins were determined thereafter. The research revealed that degradation of the anthocyanins was well described with a 1st-order reaction kinetics model and the R2 values varied in the range of 0.9059-0.9715. Activation energy of the reaction was determined to be 48537 Joule/mole. The half-lives of anthocyanins at 65°C and 75° C, and 85°C were found to be 138.63, 136.72, and 51.57, respectively. Compared the half-life periods at different temperatures, anthocyanins were found to be more resistant at 65°C and 75°C than at 85°C.

Parameters controlling the advanced oxidation degradation kinetics of nitroglycerin and pentaerythritol tetranitrate

2018 ◽  
Vol 7 (1) ◽  
pp. 61-67
Author(s):  
Do Ngoc Khue ◽  
Tran Dai Lam ◽  
Dao Duy Hung ◽  
Vu Quang Bach ◽  
Nguyen Van Anh ◽  
...  
Keyword(s):  
Advanced Oxidation Processes ◽  
Degradation Kinetics ◽  
Advanced Oxidation ◽  
Reaction Rates ◽  
Pentaerythritol Tetranitrate ◽  
Order Model ◽  
Oxidation Processes ◽  
First Order ◽  
Oxidation Degradation ◽  
Kinetics Of

AbstractSeveral advanced oxidation processes have been performed for the decomposition of ester nitrates (ENs), such as nitroglycerine (NG) and pentaerythritol tetranitrate (PETN). The reaction kinetics for removing NG and PETN by some of the advanced oxidation processes (e.g. UV-H2O2, Fenton, UV-Fenton) followed the pseudo-first-order model. The reaction rates in different systems followed the sequence ENs/UV<ENs/H2O2<ENs/UV-H2O2<ENs/Fenton<ENs/UV-Fenton. The effect of various parameters, such as pH, concentration of hydrogen peroxide, and temperature, on the degradation of NG and PETN were studied.

scholarly journals STRUCTURAL LEVELS OF THE NUCLEATION AND GROWTH OF FATIGUE CRACK IN 17MN1SI STEEL PIPELINE AFTER LONG-TERM SERVICE

Transport ◽  
2015 ◽  
Vol 30 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Pavlo Maruschak ◽  
Sergey Panin ◽  
Ilya Vlasov ◽  
Olegas Prentkovskis ◽  
Iryna Danyliuk
Keyword(s):  
Fatigue Crack ◽  
Residual Life ◽  
Degradation Kinetics ◽  
Life Time ◽  
Nucleation And Growth ◽  
Gas Pipelines ◽  
Deformation And Fracture ◽  
Structural Levels ◽  
Kinetics Of

The majority of modern gas pipelines in Ukraine, Lithuania and Russia have been operating for more than 30–40 years. The problem of forecasting residual life-time of materials comprising such gas pipelines calls for study of their degradation kinetics as well as requires to determine its relationship with the strain-force loading parameters. The aim of the paper is to study the kinetics of fracture in order to range mechanisms of cyclic deformation of 17Mn1Si steel at nucleation and growth of a fatigue crack. Flat specimens were cut out from a fragment of 17Mn1Si steel pipe after 40 years of service. Microstructures of specimens were examined. In the paper, an attempt was made to apply the combined approach to study of deformation and fracture based on the following research parameters from nonlinear fracture mechanics: physical mesomechanics and numerical fractography.

4-tert-Octylphenol Biodegradation Performance by Acinetobacter Strain Immobilized in Calcium Alginate

2012 ◽  
Vol 518-523 ◽  
pp. 272-276
Author(s):  
Yang Liu ◽  
Kun Ming Dong ◽  
Li Miao ◽  
Xiao Jian Zhou ◽  
Cui Li Jin ◽  
...  
Keyword(s):  
Half Life ◽  
Degradation Rate ◽  
Immobilized Cells ◽  
Degradation Kinetics ◽  
Artificial Seawater ◽  
Order Kinetic ◽  
Practical Applications ◽  
Degradation Rates ◽  
Acinetobacter Sp ◽  
Kinetics Of

The 4-t-octylphenol (4-t-OP) biodegradation by alginate immobilized cells of Acinetobacter sp. was compared with its respective free cells in different media. The effects of different bead densities, pH values and practical applications of artificial seawater and wastewater on the biodegradation rate of 4-t-OP were investigated. Degradation kinetics of 4-t-OP by free and immobilized cells was well fitted with first order kinetic. The immobilized Acinetobacter sp. cells could enhance the efficiency of 4-t-OP degradation. The degradation rate and 4-t-OP half-life were 97.6% and 0.7 d, respectively. Increasing level of bead amount could also improve the degradation effects, when 400 beads per 100 mL were added, the degradation rate and 4-t-OP half-life were 96.5 % and 0.2 d respectively. The immobilized Acinetobacter sp. cells could degrade 4-t-OP both in artificial seawater and wastewater. The degradation rates were 87.7% and 84.3%, respectively, indicating its potential application of removing and biodegrading 4-t-OP under practical environment.

scholarly journals Improvement of Anthocyanin Stability in Butterfly Pea Flower Extract by Co-pigmentation with Catechin

2020 ◽  
Vol 141 ◽  
pp. 03008
Author(s):  
Phoomjai Charurungsipong ◽  
Chairath Tangduangdee ◽  
Suksun Amornraksa ◽  
Suvaluk Asavasanti ◽  
Jenshinn Lin
Keyword(s):  
Degradation Kinetics ◽  
Differential Method ◽  
Pigment Ratio ◽  
Flower Extract ◽  
Zero Order Kinetics ◽  
Butterfly Pea ◽  
Anthocyanin Stability ◽  
The Stability ◽  
Stability Enhancement ◽  
Kinetics Of

Most of the food processing operations involve the use of heat which generally causes alteration, and degradation of natural pigments, resulting in lower stability. One of the stability enhancement methods is co-pigmentation. This study aimed to determine effect of catechin co-pigment on stability of anthocyanins in Clitoria ternatea (or butterfly pea flower) extract. Degradation kinetics of anthocyanins in the extract were evaluated at three temperatures (28, 60, and 90℃). The effect of co-pigment ratio (catechin: anthocyanins at 1:1, 50:1 and 100:1 by weight) on the stability of anthocyanin extract at 90℃ was determined by the pH differential method. It was found that anthocyanin degradation followed the zero- order kinetics at all temperatures; the degradation rate increased as the temperature increased. At a lower pH, anthocyanins became more stable. An increase in the co-pigment ratio significantly retarded the degradation anthocyanins at 90℃. In addition, co-pigmentation also intensified the color of butterfly pea extract. The highest anthocyanin stability was obtained at co-pigment ratio of 100:1.

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