Influence factors in the adjustment of parameters of the modified first-order kinetics equation used to model constructed wetland systems

Abstract. Degradation of reactive brilliant red X-3B (X-3B) by a UV/Mn2+/H2O2/micro- aeration method was investigated. The influencing factors of degradation of X-3B including UV irradiation, aeration, pH value, H2O2 concentration and X-3B concentration were examined. The results show that X-3B was effectively degraded by the UV/Mn2+/H2O2/micro-aeration method. The degradation rate of X-3B was obtained from weighted linear least squares analysis of the experimental data, and accorded with the pseudo-first order kinetics equation.

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A Novel Kinetics Study on H2O2 Decomposition inthe Propylene Epoxidation System in a Fixed-Bed Reactor

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2013-0044 ◽

2013 ◽

Vol 11 (1) ◽

pp. 265-269 ◽

Cited By ~ 2

Author(s):

Lina Wang ◽

Yaquan Wang ◽

Guoqiang Wu ◽

Wenping Feng ◽

Teng Zhang ◽

...

Keyword(s):

Fixed Bed ◽

Decomposition Reaction ◽

Fixed Bed Reactor ◽

Kinetics Equation ◽

Propylene Epoxidation ◽

H2o2 Decomposition ◽

First Order ◽

First Order Kinetics ◽

Reaction Activation Energy ◽

First Time

Abstract H2O2 decomposition in the propylene epoxidation system in a fixed-bed reactor was studied herein for the first time. The decomposition rate of H2O2 increased with increasing reaction temperature. The decomposition reaction followed the first-order kinetics equation at 30–50°C, whereas it did not follow the equation any longer at higher than 50°C. A kinetics equation for the H2O2 decomposition catalyzed by TS-1/SiO2 at 30–50°C was obtained, and the reaction activation energy Ea was calculated as 69.26 kJ/mol.

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Study of Modified Dry Desulfurization Ash in a Power Plant for Sequestering CO2 from a Micron-Nanoscale Perspective

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.18511 ◽

2021 ◽

Vol 21 (1) ◽

pp. 382-391

Author(s):

Jieying Cai ◽

Xiangdong Li ◽

Di Chen ◽

Qiyan Feng

Keyword(s):

Carbon Sequestration ◽

Initial Pressure ◽

Kinetics Equation ◽

Liquid Ratio ◽

Experimental Conditions ◽

X Ray ◽

First Order ◽

First Order Kinetics ◽

Before And After ◽

Solid Liquid

To improve the CO2 fixation ability of dry desulfurization ash (DDA), a DDA must be modified by chemical methods. At the micron level, the changes in microstructure and chemical composition before and after DDA modification were analysed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS), and the reaction mechanism of the modification process was inferred. On the other hand, the chemical and mineral phase compositions of the modified DDA and its solid products were analysed by X ray Fluorescence (XRF) and X-ray diffraction (XRD). In addition, the microstructure of the modified DDA before and after sequestration at nanometre resolution was studied by SEM-EDS so that the curing mechanism of the modified DDA was clearly defined. Then, the effects of the solid–liquid ratio, temperature, pressure and reaction time on the sequestration of CO2 in the modified DDA were studied with aqueous carbonation. The results showed that the higher the temperature is, the higher the solid–liquid ratio, and the lower initial pressure is, the less the CO2 sequestered in the modified DDA and the less the carbon sequestration capacity of the modified DDA. Under the experimental conditions, the carbonation efficiency of the modified DDA could reach 94.42%, and 1 ton of modified DDA could sequester up to 50.61 kg CO2. Compared with conventional DDA, the carbon sequestration capacity is effectively improved. The kinetic data confirmed that the fitting correlation of the quasi-first-order kinetics equation is more significant. The smaller the solid–liquid ratio is, the lower the temperature, the higher the initial pressure, and the higher the rate constant of the quasi-first-order kinetics equation.

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Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽

10.32964/tj17.03.167 ◽

2018 ◽

Vol 17 (03) ◽

pp. 167-178 ◽

Cited By ~ 2

Author(s):

Xin Tong ◽

Jiao Li ◽

Jun Ma ◽

Xiaoquan Chen ◽

Wenhao Shen

Keyword(s):

Degradation Rate ◽

Southern China ◽

Catalytic Degradation ◽

Pulp And Paper ◽

Gaseous Pollutants ◽

Pulp And Paper Mills ◽

Paper Mills ◽

Initial Concentration ◽

First Order ◽

First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

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Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

10.31221/osf.io/m9g7p ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Methyl Orange ◽

Solution Ph ◽

Vanadium Concentration ◽

Limiting Behavior ◽

First Order ◽

First Order Kinetics ◽

Ph Range ◽

Kinetic Pattern ◽

Triton X ◽

Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

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Biodegradation rates of aromatic contaminants in biofilm reactors

Water Science & Technology ◽

10.2166/wst.1995.0027 ◽

1995 ◽

Vol 31 (1) ◽

pp. 117-128 ◽

Cited By ~ 8

Author(s):

Jean-Pierre Arcangeli ◽

Erik Arvin

Keyword(s):

Aromatic Hydrocarbons ◽

Competitive Inhibition ◽

Removal Rate ◽

First Order ◽

Biofilm Reactors ◽

First Order Kinetics ◽

Reducing Conditions ◽

Low Concentrations ◽

Degradation Rates ◽

Order Surface

This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols, chlorophenols, nitrophenol, chlorobenzenes and aromatic nitrogen-, sulphur- or oxygen-containing heterocyclic compounds (NSO-compounds). Furthermore, a comparison with degradation rates observed for easily degradable organics is also presented. At concentrations below 20-100 μg/l the degradation of the aromatic compounds was typically controlled by first order kinetics. The first-order surface removal rate constants were surprisingly similar, ranging from 2 to 4 m/d. It appears that NSO-compounds inhibit the degradation of aromatic hydrocarbons, even at very low concentrations of NSO-compounds. Under nitrate-reducing conditions, toluene was easily biodegraded. The xylenes and ethylbenzene were degraded cometabolically if toluene was used as a primary carbon source; their removal was influenced by competitive inhibition with toluene. These interaction phenomena are discussed in this paper and a kinetic model taking into account cometabolism and competitive inhibition is proposed.

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In-vitro Kinetic Hydrolysis Study of Metronidazole Derivatives with Carvacrol and Eugenol Using Validated RP-HPLC Method

Current Pharmaceutical Analysis ◽

10.2174/1573412916999200529123151 ◽

2020 ◽

Vol 16 ◽

Author(s):

M. Alarjah

Keyword(s):

Half Life ◽

Hplc Method ◽

Hydrolysis Rate ◽

First Order ◽

First Order Kinetics ◽

Rp Hplc ◽

Pharmacokinetic Properties ◽

Pseudo First Order ◽

Kinetic Hydrolysis

Background: Prodrugs principle is widely used to improve the pharmacological and pharmacokinetic properties of some active drugs. Much effort was made to develop metronidazole prodrugs to enhance antibacterial activity and or to improve pharmacokinetic properties of the molecule or to lower the adverse effects of metronidazole. Objective: In this work, the pharmacokinetic properties of some of monoterpenes and eugenol pro metronidazole molecules that were developed earlier were evaluated in-vitro. The kinetic hydrolysis rate constants and half-life time estimation of the new metronidazole derivatives were calculated using the validated RP-HPLC method. Method: Chromatographic analysis was done using Zorbbax Eclipse eXtra Dense Bonding (XDB)-C18 column of dimensions (250 mm, 4.6 mm, 5 μm), at ambient column temperature. The mobile phase was a mixture of sodium dihydrogen phosphate buffer of pH 4.5 and methanol in gradient elution, at 1ml/min flow rate. The method was fully validated according to the International Council for Harmonization (ICH) guidelines. The hydrolysis process carried out in an acidic buffer pH 1.2 and in an alkaline buffer pH 7.4 in a thermostatic bath at 37ºC. Results: The results followed pseudo-first-order kinetics. All metronidazole prodrugs were stable in the acidic pH, while they were hydrolysed in the alkaline buffer within a few hours (6-8 hr). The rate constant and half-life values were calculated, and their values were found to be 0.082- 0.117 hr-1 and 5.9- 8.5 hr., respectively. Conclusion: The developed method was accurate, sensitive, and selective for the prodrugs. For most of the prodrugs, the hydrolysis followed pseudo-first-order kinetics; the method might be utilised to conduct an in-vivo study for the metronidazole derivatives with monoterpenes and eugenol.

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Decomposition of 4,4'-(Diazoamino)-bis(5-methoxy-2-methylbenezenesulfonic Acid) in Solutions ofFD&C Red No. 40

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/67.4.844 ◽

1984 ◽

Vol 67 (4) ◽

pp. 844-845

Author(s):

Naomi Richfield-Fratz

Keyword(s):

Liquid Chromatography ◽

Aqueous Solutions ◽

Borate Buffer ◽

Sodium Borate ◽

First Order ◽

First Order Kinetics ◽

Color Additive ◽

Sodium Borate Buffer

Abstract 4,4'-(Diazoamino)-bis(5-methoxy-2-methylbenzenesuIfonic acid), when present as a reaction by-product in FD&C Red No. 40, is shown to decompose rapidly in aqueous solutions of the color additive. The decomposition is halted by the addition of sodium borate buffer. Quantitationly liquid chromatography shows that decomposition is nonlinear with time and follows approximate first order kinetics.

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Comparative Study of Chemical Stability of Two H1Antihistaminic Drugs, Terfenadine and ItsIn VivoMetabolite Fexofenadine, Using LC-UV Methods

Journal of Analytical Methods in Chemistry ◽

10.1155/2019/5790404 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10

Author(s):

Anna Gumieniczek ◽

Anna Berecka-Rycerz ◽

Rafał Pietraś ◽

Izabela Kozak ◽

Karolina Lejwoda ◽

...

Keyword(s):

Comparative Study ◽

Chemical Stability ◽

First Order ◽

First Order Kinetics ◽

Kinetics Of Degradation ◽

Effects Of Temperature ◽

High Doses ◽

Antihistaminic Drugs ◽

Kinetics Of

A comparative study of chemical stability of terfenadine (TER) and itsin vivometabolite fexofenadine (FEX) was performed. Both TER and FEX were subjected to high temperature at different pH and UV/VIS light at different pH and then quantitatively analyzed using new validated LC-UV methods. These methods were used to monitor the degradation processes and to determine the kinetics of degradation for both the compounds. As far as the effects of temperature and pH were concerned, FEX occurred more sensitive to degradation than TER. As far as the effects of UV/VIS light and pH were concerned, the both drugs were similarly sensitive to high doses of light. Using all stress conditions, the processes of degradation of TER and FEX followed the first-order kinetics. The results obtained for these two antihistaminic drugs could be helpful in developing their new derivatives with higher activity and stability at the same time.

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The conversion of ethylene to ethylidyne on Pt(111): non-first order kinetics and ensemble effects

Surface Science ◽

10.1016/0039-6028(94)91298-x ◽

1994 ◽

Vol 301 (1-3) ◽

pp. 177-196 ◽

Cited By ~ 29

Author(s):

W. Erley ◽

Y. Li ◽

D.P. Land ◽

John C. Hemminger

Keyword(s):

First Order ◽

First Order Kinetics ◽

Ensemble Effects

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