Determining anaerobic degradation kinetics from batch tests

2016 ◽  
Vol 73 (10) ◽  
pp. 2468-2474 ◽  
Author(s):  
Iván López Moreda
Keyword(s):  
Anaerobic Degradation ◽  
Degradation Kinetics ◽  
Optimization Procedure ◽  
Organic Substrate ◽  
Distribution Functions ◽  
Multiple Shooting ◽  
Order Kinetic ◽  
First Order ◽  
Batch Tests ◽  
Monod Kinetic

Data obtained from a biomethane potential (BMP) test were used in order to obtain the parameters of a kinetic model of solid wastes anaerobic degradation. The proposed model considers a hydrolysis step with a first order kinetic, a Monod kinetic for the soluble organic substrate degradation and a first order decay of microorganisms. The instantaneous release of methane was assumed. The parameters of the model are determined following a direct search optimization procedure. A ‘multiple-shooting’ technique was used as a first step of the optimization process. The confidence interval of the parameters was determined by using Monte Carlo simulations. Also, the distribution functions of the parameters were determined. Only the hydrolysis first order constant shows a normal distribution.

Anaerobic degradation kinetics of particulate organic matter: a new approach

1997 ◽  
Vol 36 (6-7) ◽  
pp. 239-246 ◽  
Author(s):  
Andrea Valentini ◽  
Gilbert Garuti ◽  
Alberto Rozzi ◽  
Andrea Tilche
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Anaerobic Degradation ◽  
Degradation Kinetics ◽  
Kinetic Constant ◽  
Power Coefficient ◽  
Mathematical Representation ◽  
First Order ◽  
Batch Tests ◽  
Kinetics Of

The development of a reliable model of anaerobic hydrolysis is of primary importance for improving modeling and design of anaerobic treatment for wastewaters and slurries with high suspended solids concentration. Michaelis-Menten, substrate first order, substrate and biomass first order and substrate first order and biomass half order equations have been compared using experimental data from a series of anaerobic degradation batch tests on cellulose particles of known size. A general kinetic equation [dS/dt=−KHASXA] which may include all the four considered kinetics, is presented. This general equation allows for a more accurate mathematical representation of the hydrolysis process. Analysing data from a series of batch tests, the best fit value of A was found to be in the range 0.42 to 0.64. This approach could reduce the choice of anaerobic degradation kinetics of particulate organic matter to the calculation of the kinetic constant KHA and of the related power coefficient A.

Degradation of azo dye with dirhodium(II) caprolactamate as heterogeneous catalyst

2012 ◽  
Vol 65 (12) ◽  
pp. 2175-2182
Author(s):  
Abeer S. Elsherbiny ◽  
Sahar H. El-Khalafy ◽  
Michael P. Doyle
Keyword(s):  
Hydroxyl Radicals ◽  
Azo Dye ◽  
Degradation Kinetics ◽  
Oxidative Degradation ◽  
Total Carbon ◽  
Order Kinetic ◽  
First Order ◽  
Pseudo First Order ◽  
Kinetics Of ◽  
Degradation Of Azo Dye

The kinetics of the oxidative degradation of an azo dye Metanil Yellow (MY) was investigated in aqueous solution using dirhodium(II) caprolactamate, Rh2(cap)4, as a catalyst in the presence of H2O2 as oxidizing agent. The reaction process was followed by UV/Vis spectrophotometer. The decolorization and degradation kinetics were investigated and both followed a pseudo-first-order kinetic with respect to the [MY]. The effects of various parameters such as H2O2 and dye concentrations, the amount of catalyst and temperature have been studied. The studies show that Rh2(cap)4 is a very effective catalyst for the formation of hydroxyl radicals HO• which oxidized and degraded about 92% of MY into CO2 and H2O after 24 h as measured by total carbon analyzer.

Anaerobic degradation kinetics of a cholesteryl ester

2003 ◽  
Vol 48 (6) ◽  
pp. 141-147
Author(s):  
S. Gutiérrez ◽  
M. Viñas
Keyword(s):  
Palmitic Acid ◽  
Anaerobic Degradation ◽  
Drop Size ◽  
Degradation Kinetics ◽  
Relative Rate ◽  
Hydrolysis Rate ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
The Difference ◽  
Kinetics Of

The most important components of wool scouring effluent grease are esters of sterols. Cholesteryl palmitate (CP) is the main ester in this grease. In this paper, the influence of the ester concentration in the anaerobic digestion and the relative rate of the different degradation steps, are studied. The experiment was carried out to measure methane production in the anaerobic degradation of acetate, palmitic acid (PA) and CP. A first-order kinetic model was assumed for hydrolysis and Monod models were assumed for both the methanogenic and acetogenic steps. Maximum hydrolysis rate was found to be around 20 times faster than the maximum methanogenic reaction rate during the experience. The lanolin emulsion drop size effect was also evaluated employing fine and coarse stock lanolin emulsions and no adapted sludge. Concentrations of 13.7 to 4.6 gCOD.l-1 were employed. In a previous study, the effect of palmitic acid emulsion size was found important when similar sludge was tested. When esters are degraded, a significant effect of drop size on the degradation rate was not found. The difference between CP and PA emulsions behavior could be due to the fact that cholesterol produced during the ester degradation has a protective effect on the sludge.

Iridium nanoparticles with high catalytic activity in degradation of acid red-26: an oxidative approach

2016 ◽  
Vol 74 (11) ◽  
pp. 2551-2559 ◽  
Author(s):  
Anjali Goel ◽  
Rajni Lasyal
Keyword(s):  
Liquid Chromatography ◽  
Degradation Products ◽  
Degradation Kinetics ◽  
Oxidative Degradation ◽  
High Catalytic Activity ◽  
Order Kinetic ◽  
Operational Parameters ◽  
First Order ◽  
Iridium Nanoparticles ◽  
Vis Spectroscopy

Nanocatalysis using metal nanoparticles constitutes one of the emerging technologies for destructive oxidation of organics such as dyes. This paper deals with the degradation of acid red-26 (AR-26), an azo dye by hexacyanoferrate (abbreviated as HCF) (III) using iridium nanoparticles. UV-vis spectroscopy has been employed to obtain the details of the oxidative degradation of the selected dye. The effect of various operational parameters such as HCF(III) concentration, pH, initial dye concentration, catalyst and temperature was investigated systematically at the λmax, 507 nm, of the reaction mixture. Degradation kinetics follows the first order kinetic model with respect to AR-26 and Ir nano concentrations, while with respect to the HCF(III) concentration reaction it follows first order kinetics at lower concentrations, tending towards zero order at higher concentrations. Thermodynamic parameters have been calculated by studying the reaction rate at four different temperatures. The UV-vis, high performance liquid chromatography (HPLC), liquid chromatography–mass spectrometry (LC-MS) analysis of degradation products showed the formation of carboxylic acid and substituted carboxylic acids as major degradation products, which are simple and less hazardous compounds. The big advantage of the present method is the recovery and reuse of iridium nanoparticles. Moreover, turnover frequencies for each catalytic cycle have been determined, indicating the long life span of Ir nanoparticles. Thus, the finding is a novel and highly economical alternative for environmental safety against pollution by dyes, and extendable for other contaminants as well.

scholarly journals Kinetics of diatrizoate degradation by ozone and the formation of disinfection by-products in the sequential chlorination

2021 ◽  
Author(s):  
Chen-Yan Hu ◽  
Si-Cheng Ren ◽  
Yi-Li Lin ◽  
Ji-Chen Zhang ◽  
Ye-Ye Zhu ◽  
...  
Keyword(s):  
Ozone Concentration ◽  
Ph Value ◽  
Degradation Kinetics ◽  
Order Rate Constant ◽  
Order Kinetic ◽  
Solution Ph ◽  
First Order ◽  
Pseudo First Order ◽  
Kinetics Of ◽  
By Products

Abstract In this study, we studied the degradation kinetics of a common iodine contrast agent, diatrizoate, by ozone and the formation of disinfection by-products (DBPs) in the sequential chlorination. Effects of ozone concentration, solution pH, and bromide concentration on diatrizoate degradation were evaluated. The results indicate that diatrizoate can be effectively degraded (over 80% within 1 h) by ozone, and the degradation kinetics can be well described using the pseudo-first-order kinetic model. The pseudo-first-order rate constant (kobs) of diatrizoate degradation significantly increased with increasing ozone concentration and decreasing bromide concentration. The kobs kept increasing with the increase of pH value and reached a maximum of 6.5 (±0.05) × 10−2 min−1 at pH 9. As the ozone concentration gradually increased from 0.342 to 1.316 mg/L, the corresponding kobs of diatrizoate degradation increased from 1.76 (±0.20) × 10−3 to 4.22 (±0.3) × 10−2 min−1. The bromide concentration exhibited a strong inhibitory effect on diatrizoate degradation because of the competition for ozone with diatrizoate. Trichloromethane was the only detected DBP in the subsequent chlorination in the absence of bromide. However, in the presence of bromide, six other DBPs were detected, and bromochloroiodomethane and tribromomethane became the major products with concentrations 1–2 orders higher than those of the other DBPs. In order to provide safe drinking water to the public, water should be maintained at circumneutral pH values and low bromine concentrations (<5 μM) before reaching the chlorine disinfection process to effectively control the formation of DBPs.

scholarly journals Aerobic and anaerobic degradation of tannic acid on water samples from Monjolinho reservoir (São Paulo, SP, Brazil)

2002 ◽  
Vol 62 (4a) ◽  
pp. 585-590 ◽  
Author(s):  
M. B. CUNHA-SANTINO ◽  
I. BIANCHINI Jr. ◽  
L. E. F. SERRANO
Keyword(s):  
Organic Carbon ◽  
Tannic Acid ◽  
Anaerobic Degradation ◽  
High Capacity ◽  
Order Kinetic ◽  
Anaerobic Conditions ◽  
First Order ◽  
Order Kinetic Model ◽  
Carbon Concentrations ◽  
Aerobic And Anaerobic

In order to describe the transformations of tannic acid during its degradation (under aerobic and anaerobic conditions) incubations were performed. To evaluate the oxygen consumption, the tannic acid was added to 1 L of water sample from Monjolinho's reservoir (22º00'S and 47º54'W); these solutions were aerated and the dissolved oxygen was monitored for 16 days, the anaerobic process was avoided. For the anaerobic and aerobic degradation, the dissolved organic carbon and the acid tannic concentrations were estimated on the samples days. The results were fitted to first-order kinetic model, being possible to verify that during the 16 days the oxygen uptake was 3.6 mg.L-1, the deoxygenation rate (kD)of this process was 0.39 day-1. The degradation coefficients were calculated through the decay of the tannic acid and organic carbon concentrations. In the aerobic process, the global decay coefficient (kG) was 0.36 day-1 and in the anaerobic 0.28 day-1. Overall, the obtained degradation coefficients suggest that the bacterioplankton of the Monjolinho's reservoir possess a high capacity of polyphenols degradation.

scholarly journals Photocatalytic Degradation of a Basic Dye Using Zinc Oxide Nanocatalyst

2019 ◽  
Vol 81 ◽  
pp. 18-26 ◽  
Author(s):  
Maureen O. Chijioke-Okere ◽  
Nnaemeka John Okorocha ◽  
Basil N. Anukam ◽  
Emeka E. Oguzie
Keyword(s):  
Zinc Oxide ◽  
Malachite Green ◽  
Uv Light ◽  
Degradation Kinetics ◽  
Catalyst Loading ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
First Order ◽  
Malachite Green Dye ◽  
Order Kinetic Model

The potential of Calcinated and uncalcinated zinc oxide as effective Photocatatlyst for the degradation of malachite green dye, MG from aqueous medium using UV light has been identified. The photocatalysts were characterized using scanning electron microscope, SEM and x-ray diffraction, XRD. The SEM investigations of the calcinated ZnO revealed highly dispersed nanomaterials and the particles were of nanometer size in agreement with the XRD result. The uncalcinated zinc oxide, ZnO revealed some pronounced nanoparticles. The degradation of MG by the photocatalyst was found to be influenced by adsorbent loading and irradiating time. The optimum degradation was obtained at 0.5g catalyst loading of both calcinated and uncalcinated zinc oxide which is 98.48% and 96.31 % respectively at 150 minutes. The degradation kinetics conformed to the pseudo-first-order kinetic model. The present study showed that calcinated and uncalcinated zinc oxide ZnO can be effectively used as efficient photocatalyst for the degradation of Malachite green dyes from aqueous solutions and effluents.

scholarly journals Glucose effect on degradation kinetics of methyl parathion by filamentous fungi species Aspergilus Niger AN400

2011 ◽  
Vol 16 (3) ◽  
pp. 225-230 ◽  
Author(s):  
Glória Marinho ◽  
Kelly Rodrigues ◽  
Rinaldo Araujo ◽  
Zuleika Bezerra Pinheiro ◽  
Germana Maria Marinho Silva
Keyword(s):  
Aspergillus Niger ◽  
Methyl Parathion ◽  
Degradation Kinetics ◽  
Kinetic Constant ◽  
Reaction Times ◽  
Toxicity Tests ◽  
Good Representation ◽  
Order Kinetic ◽  
Glucose Effect ◽  
First Order

This study evaluated the glucose effect on the removal of methyl parathion by Aspergillus niger AN400. The study was conducted in two stages: toxicity tests on plates and assays in flasks, under an agitation of 200 rpm. The methyl parathion concentrations in the toxicity test ranged from 0.075 to 60 mg/L. The second stage consisted on evaluating reactors: six control reactors with methyl parathion solution; six reactors with fungi and methyl parathion, and six reactors containing fungi, methyl parathion, and glucose. The reaction times studied ranged from 1 to 27 days. Methyl parathion concentrations of up to 60 mg/L were not toxic for Aspergillus niger AN400. The first-order kinetic model served as a good representation of the methyl parathion conversion rate. The first-order kinetic constant was 0.063 ± 0.005 h-1 for flasks without addition of glucose, while a value of 0.162 ± 0.014 h-1 was obtained when glucose was added.

Degradation of biotansformation products of nonylphenol ethoxylates by ozonation and UV/TiO2 treatment

2002 ◽  
Vol 46 (11-12) ◽  
pp. 127-132 ◽  
Author(s):  
M. Ike ◽  
M. Asano ◽  
F.D. Belkada ◽  
S. Tsunoi ◽  
M. Tanaka ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Degradation Kinetics ◽  
Chemical Oxidation ◽  
Order Kinetic ◽  
Oxidation Processes ◽  
First Order ◽  
First Order Kinetics ◽  
Biotransformation Products ◽  
Kinetics Of ◽  
Dioxide Suspension

The degradation kinetics of biotransformation products of nonylphenol polyethoxylates (NPEOs), nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenoxy carboxylic acid (NP1EC), by ozonation and UV/TiO2 (ultraviolet photocatalytic degradation in the presence of titanium dioxide suspension as a catalyst) were investigated using lab-scale reactors. The degradation rate of NP by UV/TiO2 was the highest among the tested NPEOs metabolites, while NP1EC showed the lowest degradation rate. In contrast, ozonation was especially effective for the breakdown of NP1EC. NP could be also degraded efficiently by ozonation, however, it was much less effective for NP1EO decomposition. Degradation of NP by both chemical oxidation processes followed first-order kinetics. The degradation curves of NP1EO and NP1EC could be approximately described by first-order kinetics also, although the degradation of NP1EC by ozonation seemed to follow a second-order kinetic.

scholarly journals Thermal Degradation Kinetics and pH-Rate Profiles of Iriflophenone 3,5-C-β-d-diglucoside, Iriflophenone 3-C-β-d-Glucoside and Mangiferin in Aquilaria crassna Leaf Extract

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4898
Author(s):  
Eakkaluk Wongwad ◽  
Kornkanok Ingkaninan ◽  
Wudtichai Wisuitiprot ◽  
Boonchoo Sritularak ◽  
Neti Waranuch
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Shelf Life ◽  
Leaf Extract ◽  
Degradation Kinetics ◽  
Order Reaction ◽  
Thermal Degradation Kinetics ◽  
Order Kinetic ◽  
First Order ◽  
Aquilaria Crassna

The health benefits of the Aquilaria crassna Pierre ex Lecomte leaf extract (AE) make it very useful as an ingredient in food and pharmaceutical products. Iriflophenone 3,5-C-β-d-diglucoside (1), iriflophenone 3-C-β-d-glucoside (2) and mangiferin (3) are bioactive compounds of AE. We assessed the stability of AE by investigating the thermal degradation kinetics and shelf-life (t90%) of compounds 1, 2 and 3 using Arrhenius plot models and studied their pH-rate profiles. The results demonstrate that 1 and 2 were degraded, following a first-order kinetic reaction. The degradation of 3 followed first-order reaction kinetics when present in a solution and second-order reaction kinetics in the dried powder form of the extract. According to the first-order kinetic model, the predicted shelf-life (t90%) of the extract at 25 °C in dried form for compound 1 was 989 days with activation energy 129.86 kJ·mol−1, and for 2 it was 248 days with activation energy 110.57 kJ·mol−1, while in the extract solution, the predicted shelf-life of compounds 1–3 was 189, 13 and 75 days with activation energies 86.83, 51.49 and 65.28 kJ·mol−1, respectively. In addition, the pH-rate profiles of 1–3 indicated that they were stable in neutral to acidic environments.

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