scholarly journals Kinetic Modelling of Biodegradability Data of Commercial Polymers Obtained under Aerobic Composting Conditions

Eng ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 54-68
Author(s):  
Ilenia Rossetti ◽  
Francesco Conte ◽  
Gianguido Ramis
Keyword(s):  
Kinetic Data ◽  
Kinetic Modelling ◽  
Kinetic Equations ◽  
Second Order ◽  
Aerobic Biodegradation ◽  
First Order ◽  
First Order Kinetics ◽  
Plastic Materials ◽  
Partial Degradation ◽  
Commercial Polymers

Methods to treat kinetic data for the biodegradation of different plastic materials are comparatively discussed. Different samples of commercial formulates were tested for aerobic biodegradation in compost, following the standard ISO14855. Starting from the raw data, the conversion vs. time entries were elaborated using relatively simple kinetic models, such as integrated kinetic equations of zero, first and second order, through the Wilkinson model, or using a Michaelis Menten approach, which was previously reported in the literature. The results were validated against the experimental data and allowed for computation of the time for half degradation of the substrate and, by extrapolation, estimation of the final biodegradation time for all the materials tested. In particular, the Michaelis Menten approach fails in describing all the reported kinetics as well the zeroth- and second-order kinetics. The biodegradation pattern of one sample was described in detail through a simple first-order kinetics. By contrast, other substrates followed a more complex pathway, with rapid partial degradation, subsequently slowing. Therefore, a more conservative kinetic interpolation was needed. The different possible patterns are discussed, with a guide to the application of the most suitable kinetic model.

The Effects of Solvent and Oxygen Pressure on the Autoxidation of Benzoin Catalysed by Nickel Acetate

1979 ◽  
Vol 32 (2) ◽  
pp. 421 ◽  
Author(s):  
RP Chaplin ◽  
S Vorlow ◽  
MS Wainwright
Keyword(s):  
Free Radical ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Pressure ◽  
Second Order ◽  
Nickel Acetate ◽  
Coordination Complex ◽  
First Order ◽  
First Order Kinetics

Kinetic results are reported for the autoxidation of benzoin, catalysed by nickel acetate in methanol and ethanol. The reaction in methanol is first order with respect to benzoin and the catalyst and is independent of the oxygen partial pressure. The reaction is non-free-radical and probably involves a coordination complex between the substrate and the catalyst. In ethanol the reaction is found to obey second-order reversible kinetics with respect to benzoin and first-order kinetics with respect to the catalyst. The oxidation is also at least 10 times faster in ethanol than in methanol at 303 K.

THE INTERACTION OF METHANE AND METHANE-d4 ON NICKEL AND THE STATE OF THE CATALYST SURFACE

1949 ◽  
Vol 27b (4) ◽  
pp. 303-317 ◽  
Author(s):  
Maurice M. Wright ◽  
Hugh S. Taylor
Keyword(s):  
Kinetic Data ◽  
Surface Reaction ◽  
Catalyst Surface ◽  
Dissociative Adsorption ◽  
Fischer Tropsch ◽  
Heats Of Adsorption ◽  
First Order ◽  
First Order Kinetics ◽  
Surface Equilibrium ◽  
Adsorption Of Methane

The interaction of methane and methane-d4 on nickel has been re-examined. The data strengthen the previous concept of a dissociative adsorption of methane on the catalyst. The kinetic data indicate first-order disappearance of methane-d4 with an activation energy of 20.9 kcal. between 100° and 255 °C. Poisoning by carbonaceous residues occurs at all temperatures. First-order kinetics are indicated for the formation of methane-d3 and methane-d2 on the catalyst surface. Reaction of hydrogen with surface residues, after an exchange reaction, indicate that CX, CX2, and CX3 fragments are present on the surface where X is H or D. Higher temperatures favor an equilibrium between these fragments on the surface, equilibrium being displaced towards CX3 as temperature increases. This equilibrium will be dependent on the heats of adsorption of the fragments and of hydrogen on the surface and therefore involves also the metal used as catalyst. The data suggest a basic approach to the mechanism of the Fischer–Tropsch synthesis on metal catalysts.

Some observations on the kinetics of the Jaffé reaction for creatinine.

1977 ◽  
Vol 23 (9) ◽  
pp. 1527-1530 ◽  
Author(s):  
R M Shoucri ◽  
M Pouliot
Keyword(s):  
Rate Constants ◽  
Kinetic Data ◽  
Serum Samples ◽  
First Order ◽  
Order Rate ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Kinetics Of

Abstract The Jaffé reaction for creatinine assay appears to follow pseudo-first-order kinetics; first-order rate constants are different for different samples. Rate constants for 10 different serum samples varied from a low value of 0.0040 +/- 0.0003 s-1 to 0.0084 +/- 0.0008 s-1. We describe an approach for determining first-order rate constants from kinetic data and discuss the effects of the above observations on the mathematical formulations required for reliable kinetic determinations of creatinine.

scholarly journals Empirical Kinetic Modelling of the Effect of l-Ascorbic Acid on the Cu(II)-Induced Oxidation of Quercetin

2018 ◽  
Vol 2 (4) ◽  
pp. 46
Author(s):  
Nikoletta Bobolaki ◽  
Angelos Photiades ◽  
Spyros Grigorakis ◽  
Dimitris Makris
Keyword(s):  
Mass Spectrometry ◽  
Ascorbic Acid ◽  
Superoxide Anion ◽  
Protocatechuic Acid ◽  
Kinetic Modelling ◽  
Oxidation Products ◽  
Diode Array ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range

This study aimed at investigating the effect of l-ascorbic acid on the Cu2+-induced oxidation of quercetin, within a pH range from 6.7 to 8.3 and temperatures varying from 53 to 87 °C. Initial examinations showed that quercetin degradation obeyed apparent first-order kinetics and it was significantly affected by temperature. Modelling of the effect of l-ascorbic acid by implementing response surface methodology suggested that l-ascorbic acid did not impact quercetin oxidation significantly (p < 0.05) and led to an empirical kinetic model based on temperature (T) and pH. Liquid chromatography–diode array–mass spectrometry analyses revealed the presence of typical quercetin degradation and oxidation products, including protocatechuic acid and 2-(hydroxybenzoyl)-2-hydroxybenzofuran-3(2H)-one. It was concluded that the formation of l-ascorbyl or other radicals (superoxide anion) may be involved in quercetin oxidation and this fact merits further attention to illuminate the possible beneficial or adverse nutritional consequences of such reactions in foods.

Nitrogen Bridged Osmium-Ruthenium Complexes

1971 ◽  
Vol 49 (2) ◽  
pp. 207-210 ◽  
Author(s):  
Clive M. Elson ◽  
J. Gulens ◽  
John A. Page
Keyword(s):  
Absorption Band ◽  
Ruthenium Complexes ◽  
Second Order ◽  
Kcal Mole ◽  
First Order ◽  
First Order Kinetics ◽  
Equilibrium Concentrations

The formation of [(H2O)(NH3)4Ru—N2—Os(NH3)5]4+ by the reaction of cis-Ru(NH3)4(H2O)22+and Os(NH3)5N22+ has been studied over the range 15–45 °C. The reaction followed second order kinetics with kt = 1.2 × 10–1 M–1 s–1 at 25.0 °C and Ea = 16.8 ± 0.1 kcal/mole. Measurement of equilibrium concentrations gave Keq = 4 × 103 M−1 at 25.0 °C.The (4+) dimer was stable but removal of the excess cis-Ru(NH3)4(H2O)22+ reactant by oxidation at −0.10 V was followed by dimer decomposition. The breakup obeyed simple first order kinetics with kr = 2.9 × 10−5 s−1 at 25.0 °C.Oxidation of the (4+) dimer at + 0.10 V gave a stable (5+) dimer. Removal of the excess Os(NH3)5N22+ reactant at + 0.30 V was followed by decomposition of the (5+) dimer giving Os(NH3)5N22+ and RuIII(NH3)4X2. The decomposition again obeyed first order kinetics with k1 = 1.5 × 10−5 s−1 at 25.0 °C. The (5+) dimer has an intervalence–transfer absorption band at 755 nm and is characterized as [X(NH3)4RuIII—N2—OsII(NH3)5]5+.The studies were carried out in an aqueous H2SO4–K2SO4 electrolyte of pH 3.3, µ = 0.30.

Study for Absorption Heavy Metals by Pickled Diatomite

2013 ◽  
Vol 741 ◽  
pp. 55-58
Author(s):  
Wen Lian Luo
Keyword(s):  
Experimental Data ◽  
Heavy Metals ◽  
Kinetic Data ◽  
Second Order ◽  
Order Kinetic ◽  
Equilibrium Isotherms ◽  
First Order ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Pseudo First Order

The removal of Cu2+ ions from aqueous solution was studied using pickled diatomite samples. The linear Langmuir and Freundlich adsorption equations were applied to describe the equilibrium isotherms. The pseudo-first-order and pseudo-second-order models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model.

On BOD tests for the determination of biodegradable COD for Calibrating Activated Sludge Model No. 1

1999 ◽  
Vol 39 (4) ◽  
pp. 177-184 ◽  
Author(s):  
Stefan R. Weijers
Keyword(s):  
Activated Sludge ◽  
Conversion Factor ◽  
Nitrification Inhibitor ◽  
Second Order ◽  
Activated Sludge Model ◽  
First Order ◽  
First Order Kinetics ◽  
Quantitative Basis ◽  
Parameter Values

Application of Activated Sludge Model No. 1 requires an influent characterisation of COD over the different model COD components. Total biodegradable COD (CODBD) is the most important quantity in this characterisation. The use and interpretation of BOD tests for the determination of biodegradable COD were investigated. Of four grab samples, the BOD evolution in time was measured up to fifteen days, with addition of nitrification inhibitor. From the BOD curves, total BOD (BOD∞, or BOD infinite) was estimated with first and second-order models. Parameters were fitted with one (or two, for the second-order models) kinetic parameter per individual sample as well as one (two) for all samples together. The BOD curves were adequately described by first-order kinetics. The estimated kinetic parameters showed considerable variation over the samples from the same wastewater. As a consequence, the ratio BOD∞/BOD5 was not constant for a given wastewater. The ratio BOD∞/CODtot on the contrary proved much more constant. Therefore, the total COD instead of BOD5 is suggested as a basis for determination of biodegradable COD. The BOD∞ estimated has to be converted to CODBD. The conversion factor was computed by simulating the BOD tests using ASM1, reduced for aerobic conditions. This approach provides a quantitative basis for this conversion factor. The sensitivity of this conversion factor to model parameter values and COD fractionation was determined, which showed that the conversion has to be adjusted for non-default values of the heterotrophic yield.

THE CHEMISORPTION OF NITROGEN ON POLYCRYSTALLIN TUNGSTEN WIRES

1965 ◽  
Vol 43 (4) ◽  
pp. 532-546 ◽  
Author(s):  
L. J. Rigby
Keyword(s):  
Activation Energy ◽  
Room Temperature ◽  
Second Order ◽  
Mass Spectrometric ◽  
Kcal Mole ◽  
First Order ◽  
First Order Kinetics ◽  
Α Phase ◽  
Polycrystalline Tungsten ◽  
Mass Spectrometric Evidence

Desorption spectra have been obtained for successively increasing amounts of nitrogen adsorbed on three polycrystalline tungsten wires at room temperature. Two β phases were desorbed, β1 with first-order kinetics and an activation energy of 73 kcal/mole and β2with second-order kinetics and an activation energy of 75 kcal/mole. Surface impurities such as carbon or thorium reduced the size of the β1 phase. Mass spectrometric evidence showed that the small α phase was adsorbed as molecules, and the β1 and β2 phases were adsorbed as atoms.

Nonlinear Analysis of Visual Evoked Potentials Elicited by Color Stimulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 315-318 ◽  
Author(s):  
K. Momose ◽  
K. Komiya ◽  
A. Uchiyama
Keyword(s):  
Visual System ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Normal Subjects ◽  
Second Order ◽  
First Order ◽  
The Relationship ◽  
Perceived Color ◽  
Second Order Nonlinearity ◽  
Visual Evoked

Abstract:The relationship between chromatically modulated stimuli and visual evoked potentials (VEPs) was considered. VEPs of normal subjects elicited by chromatically modulated stimuli were measured under several color adaptations, and their binary kernels were estimated. Up to the second-order, binary kernels obtained from VEPs were so characteristic that the VEP-chromatic modulation system showed second-order nonlinearity. First-order binary kernels depended on the color of the stimulus and adaptation, whereas second-order kernels showed almost no difference. This result indicates that the waveforms of first-order binary kernels reflect perceived color (hue). This supports the suggestion that kernels of VEPs include color responses, and could be used as a probe with which to examine the color visual system.

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

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 167-178 ◽  
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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