Rigid and film bioplastics degradation under suboptimal composting conditions: A kinetic study

The present research investigates the degradation rate of bioplastics under various composting conditions, including suboptimal ones. Lab-scale tests were carried out setting three variables: temperature (37°C–58°C), humidity (30%–60%) and duration of the thermophilic and the maturation phases (15–60 days). The composting tests were carried out following modified guideline ISO 20200:2015 and lasted for 60 days. Bioplastics in the synthetic waste matrix consisted of Mater-Bi® film biobags and PLA rigid teaspoons. A kinetic study was performed, resulting in faster degradation rates for film bioplastics (first-order kinetics with k = 0.0850–0.1663 d−1) than for rigid (0.0018–0.0136 d−1). Moreover, film bioplastics reached a complete degradation within the 60 days of the test. Concerning the rigid products, 90% degradation would be achieved in 2–3 years for mesophilic conditions. Finally, in the undersieve of 0.5 mm some microplastics were identified with the ImageJ software, mainly relatable to rigid (PLA) bioplastics. Overall, the results disclosed that the combination of mesophilic temperatures and absence of moistening slowed down both the degradation and the disintegration process of bioplastics.

Download Full-text

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.

Download Full-text

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.

Download Full-text

Azides. Part V. A kinetic study of the formation of N-(p-toluenesulphonyl)-1H-azepine by thermolysis of p-toluenesulphonylazide in benzene under nitrogen pressure

Canadian Journal of Chemistry ◽

10.1139/v85-147 ◽

1985 ◽

Vol 63 (4) ◽

pp. 887-890 ◽

Cited By ~ 2

Author(s):

Nagaraj R. Ayyangar ◽

Ramesh B. Bambal ◽

Dattatraya D. Nikalje ◽

Kumar V. Srinivasan

Keyword(s):

Kinetic Study ◽

Rate Constants ◽

Nitrogen Pressure ◽

Time Profile ◽

First Order ◽

First Order Kinetics ◽

Concentration Time

The course of thermolysis of p-toluenesulphonylazide (A) in benzene at 160 °C and 40.1 atm of nitrogen pressure was followed by analysis of the reactants and products in the reaction mixture by hplc. The rate measurements indicate that the reaction follows first-order kinetics with respect to the formation of N-(p-toluenesulphonyl)-1H-azepine (B) and p-toluencsulphonamide (D). The concentration–time profile is consistent with the formation of p-toluenesulphonylanilide (C) from the azepine (B). The rate constants indicate that the azepine (B) decomposes to the anilide (C) at the same rate at which it is formed.

Download Full-text

Efficient degradation of naproxen by persulfate activated with zero-valent iron: performance, kinetic and degradation pathways

Water Science & Technology ◽

10.2166/wst.2020.263 ◽

2020 ◽

Vol 81 (10) ◽

pp. 2078-2091

Author(s):

Shuyu Dong ◽

Xiaoxue Zhai ◽

Ruobing Pi ◽

Jinbao Wei ◽

Yunpeng Wang ◽

...

Keyword(s):

Aqueous Solution ◽

Hydroxyl Radical ◽

Rate Constants ◽

Zero Valent Iron ◽

Degradation Pathways ◽

First Order ◽

First Order Kinetics ◽

Degradation Rates ◽

Initial Ph ◽

Pseudo First Order

Abstract Degradation of naproxen (NAP) by persulfate (PS) activated with zero-valent iron (ZVI) was investigated in our study. The NAP in aqueous solution was degraded effectively by the ZVI/PS system and the degradation exhibited a pseudo-first-order kinetics pattern. Both sulfate radical (SO4•−) and hydroxyl radical (HO•) participate in the NAP degradation. The second-order rate constants for NAP reacting with SO4•− and HO• were (5.64 ± 0.73) × 109 M−1 s−1 and (9.05 ± 0.51) × 109 M−1 s−1, respectively. Influence of key parameters (initial pH, PS dosage, ZVI dosage, and NAP dosage) on NAP degradation were evaluated systematically. Based on the detected intermediates, the pathways of NAP degradation in ZVI/PS system was proposed. It was found that the presence of ammonia accelerated the corrosion of ZVI and thus promoted the release of Fe2+, which induced the increased generation of sulfate radicals from PS and promoted the degradation of NAP. Compared to its counterpart without ammonia, the degradation rates of NAP by ZVI/PS were increased to 3.6–17.5 folds and 1.2–2.2 folds under pH 7 and pH 9, respectively.

Download Full-text

Effect of Ultrasonic Frequency on Chlorpyrifos Degradation in Sonolytic Ozonolysis

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.587-589.578 ◽

2014 ◽

Vol 587-589 ◽

pp. 578-581

Author(s):

Jin Zhu ◽

Chang Ping Zhu ◽

Bin Wang ◽

Run Hang Gong ◽

Qing Gong Ren ◽

...

Keyword(s):

Synergistic Effect ◽

Degradation Rate ◽

Degradation Kinetics ◽

Degradation Pathway ◽

Frequency Effect ◽

Ultrasonic Frequency ◽

Kinetics Parameters ◽

First Order ◽

First Order Kinetics ◽

Degradation Reaction

The degradation of chlorpyrifos is investigated with the treatments of sonolysis, ozonolysis, and sonolytic ozonolysis at various frequencies. Results show that there exists frequency effect in sonolytic ozonolysis. In sonolytic ozonolysis, the maximum degradation rate is obtained at 495 kHz, and the degradation kinetics is fitted to the first-order kinetics model well. However, the most significant synergistic effect between ultrasonic and ozone is at 124 kHz. The kinetics parameters indicate that chlorpyrifos is much more labile to ultrasonic at 495 kHz, while ozone is much more soluble at 124 kHz. The hydrolysis and oxidation are deduced to contribute to the degradation reaction and the degradation pathway for chlorpyrifos degradation is proposed.

Download Full-text

Modeling the Effect of Plants and Peat on Evapotranspiration in Constructed Wetlands

International Journal of Chemical Engineering ◽

10.1155/2010/412734 ◽

2010 ◽

Vol 2010 ◽

pp. 1-6 ◽

Cited By ~ 9

Author(s):

Florent Chazarenc ◽

Simon Naylor ◽

Yves Comeau ◽

Gérard Merlin ◽

Jacques Brisson

Keyword(s):

Phragmites Australis ◽

Constructed Wetlands ◽

Typha Latifolia ◽

Growth Conditions ◽

First Order ◽

First Order Kinetics ◽

Hydraulic Behaviour ◽

Degradation Rates ◽

Wide Range ◽

Main Effect

Evapotranspiration (ET) in constructed wetlands (CWs) represents a major factor affecting hydrodynamics and treatment performances. The presence of high ET was shown to improve global treatment performances, however ET is affected by a wide range of parameters including plant development and CWs age. Our study aimed at modelling the effect of plants and peat on ET in CWs; since we hypothesized peat could behave like the presence of accumulated organic matter in old CWs. Treatment performances, hydraulic behaviour, and ET rates were measured in eight 1 m2CWs mesocosm (1 unplanted, 1 unplanted with peat, 2 planted withPhragmites australis, 2 planted withTypha latifoliaand 2 planted withPhragmites australiswith peat). Two models were built using first order kinetics to simulate COD and TKN removal with ET as an input. The effect of peat was positive on ET and was related to the better growth conditions it offered to macrophytes. Removal efficiency in pilot units with larger ET was higher for TKN. On average, results show for COD ak20value of 0.88d-1and 0.36d-1for TKN. We hypothesized that the main effect of ET was to concentrate effluent, thus enhancing degradation rates.

Download Full-text

Photodegradation of levofloxacin in aqueous and organic solvents: A kinetic study

Acta Pharmaceutica ◽

10.2478/acph-2013-0011 ◽

2013 ◽

Vol 63 (2) ◽

pp. 223-229 ◽

Cited By ~ 21

Author(s):

Iqbal Ahmad ◽

Raheela Bano ◽

Muhammad Ali Sheraz ◽

Sofia Ahmed ◽

Tania Mirza ◽

...

Keyword(s):

Dielectric Constant ◽

Degradation Rate ◽

Hplc Method ◽

Ph Profile ◽

Degree Of Ionization ◽

First Order ◽

First Order Kinetics ◽

Anionic Species ◽

Ph Range ◽

Kinetics Of

The kinetics of photodegradation of levofloxacin in solution on UV irradiation in the pH range 2.0-12.0 has been studied using a HPLC method. Levofloxacin undergoes first-order kinetics in the initial stages of the reaction and the apparent first-order rate constants are of the order of 0.167 to 1.807×10-3 min-1. The rate-pH profile is represented by a curve indicating the presence of cationic, dipolar and anionic species during the reaction. The singly ionized form of the molecule is non-fluorescent and is less susceptible to photodegradation. The increase in the degradation rate in the pH range 5.0-9.0 may be due to greater reactivity of the ionized species existing in that range. The rate appears to vary with a change in the degree of ionization of the species present in a particular pH range and their susceptibility to photodegradation. Above pH 9, the decrease in the rate of photodegradation may be a result of deprotonation of the piperazinyl group. The levofloxacin molecule is more stable in the pH range around 7, which is then suitable for formulation purposes. The photodegradation of levofloxacin was found to be affected by the dielectric constant and viscosity of the medium

Download Full-text

Degradation kinetics and in vitro digestive stability of selected bioactive compounds from a beverage formulated with butterfly pea flowers

Ciência Rural ◽

10.1590/0103-8478cr20210146 ◽

2022 ◽

Vol 52 (5) ◽

Author(s):

Renata Oliveira Santos ◽

Laura Monteiro Keller ◽

Vanessa Sales de Oliveira ◽

Carlos Alberto Bucher ◽

José Lucena Barbosa Junior ◽

...

Keyword(s):

Ascorbic Acid ◽

Degradation Rate ◽

Degradation Kinetics ◽

Model Systems ◽

First Order ◽

Ph Values ◽

First Order Kinetics ◽

Butterfly Pea ◽

Effects Of Temperature

ABSTRACT: This study evaluated the effects of temperature on the pH of extracts of ascorbic acid and anthocyanins from petals of butterfly pea, as well as their in vitro digestive stability in model systems at 60, 70, and 80 °C. The pH values significantly decreased with an increase in the temperature (P < 0.05). The findings were similar for the degradation of anthocyanins and ascorbic acid, which followed first-order kinetics in all the systems. The samples heated at 80 °C presented the highest degradation rate (kobs), as well as higher percentages of degradation at the end of digestive stability in vitro.

Download Full-text

Kinetic Study of SN2 Reaction between Paranitrophenyl Benzoate and Hydrazine in the Presence of CTAB Reverse Micelles

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS ◽

10.9767/bcrec.16.4.11036.744-751 ◽

2021 ◽

Vol 16 (4) ◽

pp. 744-751

Author(s):

K. Bhargavi ◽

P. Shyamala ◽

M. Padma ◽

K. V. Nagalakshmi

Keyword(s):

Open Access ◽

Kinetic Study ◽

Reverse Micelles ◽

Cetyltrimethylammonium Bromide ◽

Micellar Medium ◽

Water Pool ◽

First Order ◽

First Order Kinetics ◽

Open Access Article ◽

Reverse Micellar

Kinetic study of the reaction between p-Nitrophenyl benzoate (PNPB) by hydrazine (HYN) in the presence of Cetyltrimethylammonium bromide (CTAB)/Chloroform/Hexane reverse micellar medium shows that the reaction obeys first order kinetics with respect to each of the reactants. The rate of the reaction is much slower in reverse micellar medium compared to aqueous medium under identical conditions (kˈAq = 2.84×10−3 sec−1, krm =1.34×10−4 sec−1). The rate constants for the reaction in the reverse micellar medium have been determined at different values of W {W=[H2O]/[CTAB]} and at different concentrations of CTAB. It was found that the observed rate constant decreases with W. This kinetic behaviour was interpreted by using modified Berezin pseudo phase model, taking into consideration the distribution of the reactants, PNPB and hydrazine between the three pseudo phases, i.e., water pool, interface an organic phase. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Download Full-text

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts

Water Science & Technology ◽

10.2166/wst.2013.820 ◽

2013 ◽

Vol 69 (6) ◽

pp. 1219-1226

Author(s):

C. Chen ◽

Q. Xie ◽

B. Q. Hu ◽

X. L. Zhao

Keyword(s):

Organic Matter ◽

Activated Carbon ◽

Degradation Rate ◽

Sol Gel ◽

Oxygen Demand ◽

Solution Ph ◽

First Order ◽

First Order Kinetics ◽

Catalyst Dosage ◽

H2o2 Addition

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol–gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate.

Download Full-text