Heptachlor degradation characteristics of a novel strain and its application

Abstract With heptachlor as the sole carbon source, an effective heptachlor-degrading microorganism (named strain H) was isolated from the sludge of heptachlor-polluted sewage of a chemical plant, via enrichment, screening and purification. Strain H was identified as a facultative anaerobic Gram-negative bacterial strain belonging to genus Shigella based on the physiological-biochemical characteristics and the similarity analysis of its 16S rDNA gene sequence with the sequences logged in the Ribosomal Database Project and GenBank databases. When the optimal inoculation volume and the pH were 20% and 7.1–7.6, respectively, strain H was able to degrade heptachlor by more than 88.2% after130 h, with initial concentration of heptachlor being 300 μg/L at 30 ± 0.5 °C. It was also shown that strain H can grow on the degradation products of heptachlor such as 1-hydroxychlordene or heptachlor epoxide. Furthermore, additional carbon sources can accelerate the degradation rate of heptachlor because of co-metabolism. The degradation dynamics could be described by a first-order reaction model. A real-world field experiment demonstrated that strain H was effective in practical applications of heptachlor biodegradation in contaminated soil.

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Microbial degradation of estrogens using activated sludge and night soil-composting microorganisms

Water Science & Technology ◽

10.2166/wst.2004.0510 ◽

2004 ◽

Vol 50 (8) ◽

pp. 153-159 ◽

Cited By ~ 17

Author(s):

J.H. Shi ◽

Y. Suzuki ◽

S. Nakai ◽

M. Hosomi

Keyword(s):

Activated Sludge ◽

Microbial Degradation ◽

Estrogenic Activity ◽

Degradation Products ◽

Order Reaction ◽

Yeast Two Hybrid ◽

First Order ◽

Natural Estrogens ◽

17Β Estradiol ◽

Two Hybrid

In order to investigate the potential for microbial degradation of estrogens, and the products formed, activated sludge collected from Korea (ASK) and night soil-composting microorganisms (NSCM) were used to degrade estrogens. Results showed that both ASK and NSCM degraded almost 100% of the natural estrogens estrone (E1), 17β-estradiol (E2), and estriol (E3) from initial concentrations of 20-25 mg/L, while synthetic estrogen, ethynylestradiol (EE2), was not degraded. Analysis of degradation products of E2 by using HPLC-ECD and a consecutive first-order reaction calculation confirmed that E2 was sequentially degraded to E1, which was further degraded to other unknown compounds by ASK and NSCM. We then used the yeast two-hybrid assay to show that the unknown degradation products did not appear to possess estrogenic activity when E1, E2 or E3 were degraded to below the detection limit after 14 days of incubation, indicating that ASK and NSCM not only degrade natural estrogens, but also remove their estrogenic activities.

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Kinetics of Cs adsorption/desorption on granite by a pseudo first order reaction model

Journal of Radioanalytical and Nuclear Chemistry ◽

10.1007/s10967-007-7045-y ◽

2007 ◽

Vol 275 (3) ◽

pp. 555-562 ◽

Cited By ~ 15

Author(s):

Shih-Chin Tsai ◽

Tsing-Hai Wang ◽

Yuan-Yaw Wei ◽

Wen-Chun Yeh ◽

Yi-Lin Jan ◽

...

Keyword(s):

Reaction Model ◽

Order Reaction ◽

First Order Reaction ◽

Pseudo First Order Reaction ◽

First Order ◽

Pseudo First Order ◽

Adsorption Desorption ◽

Kinetics Of

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Evaluation of Thermal Evolution Profiles and Estimation of Kinetic Parameters for Pyrolysis of Coal/Corn Stover Blends Using Thermogravimetric Analysis

Journal of Fuels ◽

10.1155/2014/914856 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 8

Author(s):

Abhijit Bhagavatula ◽

Gerald Huffman ◽

Naresh Shah ◽

Rick Honaker

Keyword(s):

Thermogravimetric Analysis ◽

Kinetic Parameters ◽

Corn Stover ◽

Thermal Evolution ◽

Reaction Model ◽

Order Reaction ◽

First Order Reaction ◽

First Order ◽

Temperature Regimes ◽

Lignite Coal

The thermal evolution profiles and kinetic parameters for the pyrolysis of two Montana coals (DECS-38 subbituminous coal and DECS-25 lignite coal), one biomass sample (corn stover), and their blends (10%, 20%, and 30% by weight of corn stover) have been investigated at a heating rate of 5°C/min in an inert nitrogen atmosphere, using thermogravimetric analysis. The thermal evolution profiles of subbituminous coal and lignite coal display only one major peak over a wide temperature distribution, ~152–814°C and ~175–818°C, respectively, whereas the thermal decomposition profile for corn stover falls in a much narrower band than that of the coals, ~226–608°C. The nonlinearity in the evolution of volatile matter with increasing percentage of corn stover in the blends verifies the possibility of synergistic behavior in the blends with subbituminous coal where deviations from the predicted yield ranging between 2% and 7% were observed whereas very little deviations (1%–3%) from predicted yield were observed in blends with lignite indicating no significant interactions with corn stover. In addition, a single first-order reaction model using the Coats-Redfern approximation was utilized to predict the kinetic parameters of the pyrolysis reaction. The kinetic analysis indicated that each thermal evolution profile may be represented as a single first-order reaction. Three temperature regimes were identified for each of the coals while corn stover and the blends were analyzed using two and four temperature regimes, respectively.

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Kajian Dehidroksilasi Termal Kaolin menjadi Metakaolin menggunakan Analisis Termogravimetri

ALCHEMY Jurnal Penelitian Kimia ◽

10.20961/alchemy.17.1.47337.105-112 ◽

2021 ◽

Vol 17 (1) ◽

pp. 105

Author(s):

Aprilina Purbasari ◽

Tjokorde Walmiki Samadhi

Keyword(s):

Fourier Transform ◽

Thermogravimetric Analysis ◽

Fourier Transform Infrared ◽

Reaction Model ◽

Order Reaction ◽

X Ray Diffraction ◽

Exponential Factor ◽

X Ray ◽

First Order ◽

Air Atmosphere

Kaolin merupakan mineral yang banyak dimanfaatkan di berbagai industri. Kaolin dapat diubah menjadi metakaolin yang lebih reaktif melalui proses dehidroksilasi termal. Pada penelitian ini, proses dehidroksilasi termal kaolin dari Bangka Belitung menjadi metakaolin dikaji menggunakan analisis termogravimetri pada rentang suhu 30 – 900 °C dengan laju pemanasan 10 °C/menit dalam lingkungan atmosfer udara. Kaolin mengalami empat tahap dekomposisi dan dehidroksilasi kaolin menjadi metakaolin terjadi pada suhu sekitar 450 – 600 °C. Berdasarkan metode Coats dan Redfern, dehidroksilasi kaolin mengikuti model reaksi order satu dengan energi aktivasi 271,66 kJ/mol dan faktor pre-eksponensial 6,13×1015 s-1. Hasil analisis menggunakan spektroskopi X-ray diffraction (XRD) dan Fourier Transform Infrared (FTIR) pada kaolin setelah dipanaskan pada suhu 550 °C selama 3 jam menunjukkan bahwa sebagian besar kaolin telah berubah menjadi metakaolin.Study of Thermal Dehydroxylation of Kaolin to Metakaolin using Thermogravimetric Analysis. Kaolin is a mineral that is widely used in various industries. Kaolin can be converted into metakaolin which is more reactive through thermal dehydroxylation processes. In this study, thermal dehydroxylation process of Bangka Belitung kaolin into metakaolin was studied using thermogravimetric analysis in a temperature range of 30 – 900 °C with a heating rate of 10 oC/min in an air atmosphere condition. Kaolin underwent four stages of decomposition and dehydroxylation of kaolin into metakaolin occured at temperatures around 450 – 600 °C. Based on the Coats and Redfern method, kaolin dehydroxylation followed first order reaction model with activation energy of 271.66 kJ/mol and pre-exponential factor of 6.13×1015 s-1. The analysis using X-ray diffraction (XRD) dan Fourier Transform Infrared (FTIR) spectroscopy on kaolin after heating at temperature of 550 °C for 3 hours showed that most of the kaolin had turned into metakaolin.

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Oxidation Chemistry of Primary and Secondary Antioxidants

World Tribology Congress III, Volume 1 ◽

10.1115/wtc2005-63592 ◽

2005 ◽

Author(s):

T. E. Karis ◽

M. D. Carter

Keyword(s):

Heat Flow ◽

Heating Rate ◽

Combustion Temperature ◽

Reaction Model ◽

Order Reaction ◽

First Order Reaction ◽

Heat Flow Rate ◽

Base Oil ◽

First Order ◽

End Use

Inhibition of oil oxidation is the key to long life of synthetic lubricants operating in thermal stress and boundary lubrication environments [1]. Bench-scale tests to screen oil formulations provide a rapid means for optimizing formulations prior to longer running verification tests done with the oil in the end-use application [2]. The ultimate goal of accelerated oil life tests is to link the sample combustion temperature, or induction time, at a given heating rate, or temperature, to the estimated lifetime under normal use temperatures. A first order reaction model has recently been employed to derive kinetic parameters from the heating rate dependence of the combustion temperature in the non-isothermal pressure DSC (NIPDSC) test by Adhvaryu et al. [3]. The first order reaction model [4] is also employed here, but we show that a more detailed scheme is needed to fit the heat flow during the combustion exotherm. The detailed kinetic model also provides the link between the NIPDSC test and the isothermal pressure DSC test, as well lifetime estimation at temperatures closer to the end-use conditions. Although isothermal PDSC is useful on grease [5], it does not provide a sharp exotherm for the unthickened base oil [6]. The NIPDSC test provides a reasonably sharp exotherm for formulated base oil in a relatively short amount of time. In the NIPDSC test, 10–12 mg of oil is placed in an open DSC pan. The sample chamber is pressurized with oxygen. The sample temperature is linearly increased with time until the occurrence of the combustion exotherm. The exotherm peak temperature and total heat flow did not exhibit any regular dependence on oxygen pressure between 0.55 and 3.4 MPa. The base oil was an (average) C7 ester of pentaerythritol. Primary antioxidants were hindered phenol and aromatic amines, and Zn-dialkyldithiocarbamate (ZDTC) and Zn-dialkyldithiophosphate (ZDDP) were used as secondary antioxidants. For some of the tests, soluble catalyst [2] was incorporated as iron (III) 2-ethylhexanoate. The reduced heat flow thermograms during the NIPDSC test on the base oil are shown in Fig. 1. The curves are normalized by the peak heat flow rate as Q/Qp, and the symbols denote curves from the first order reaction model, discussed below. The exotherm temperature increases and the exotherm sharpens with increased heating rate. At the 20 °C/min heating rates, the internal heating upon combustion noticeably skews the shape of the exotherm.

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Kinetic model for the biotransformation of tetrachloroethylene in groundwater

Water Science & Technology ◽

10.2166/wst.1994.0293 ◽

1994 ◽

Vol 30 (7) ◽

pp. 13-18 ◽

Cited By ~ 3

Author(s):

K. Ninomiya ◽

M. Sakai ◽

E. Ohba ◽

N. Kashiwagi

Keyword(s):

Environmental Fate ◽

Reaction Model ◽

Order Reaction ◽

Kinetic Constants ◽

Contamination Level ◽

Initial Amount ◽

Molar Percentage ◽

Soil Microcosms ◽

First Order ◽

Kinetics Of

The biotransformation of tetrachloroethylene (PCE) to trichloroethylene (TCE) and then to cis-1,2-dichloroethylene (cis-DCE) under an anaerobic condition was studied using static soil microcosms. The kinetics of the biotransformation could be well approximated by the consecutive first-order reaction model, PCE →k1 TCE →k2 cis-DCE This model implied that the total amount of the above three compounds was always constant and was equal to the initial amount of PCE, even if the amount of each compound changed with time. Based on this stoichiometric relationship, two indices to characterize groundwater contamination with PCE were derived. The first was the total contamination level which was defined by the total molarity of the three compounds. The second was the degradation level which was defined by the total molar percentage of the products (TCE+DCE). These indices enabled us to evaluate the initial molarity of the pollutant PCE and the degree of the degradation. The kinetic theory also provided a useful rule such that the same time-concentration profile was obtained for the same ratio of the kinetic constants k2/k1, even if the scale of time changed. This rule enabled us to estimate the ratio of the kinetic constants, which suggested environmental fate of groundwater, from observed molarities of the three compounds.

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Potential of ozonation for the degradation of antibiotics in wastewater

Water Science & Technology ◽

10.2166/wst.2007.427 ◽

2007 ◽

Vol 55 (12) ◽

pp. 321-326 ◽

Cited By ~ 17

Author(s):

V. Yargeau ◽

C. Leclair

Keyword(s):

Bacterial Infections ◽

Reaction Order ◽

Degradation Products ◽

Order Reaction ◽

Published Data ◽

Second Order Reaction ◽

Promising Technique ◽

First Order ◽

Treatment Conditions ◽

Ft Ir

Increasing concern in recent years over the occurrence and fate of low-level concentrations of pharmaceuticals in the aquatic environment stimulates research on alternative treatment methods. This paper presents a study of the degradation of sulphamethoxazole, an antibiotic used on humans and animals in order to treat various bacterial infections, by ozonation. After 4.5 min of treatment, the concentration of sulphamethoxazole was below the HPLC detection limit of 0.6 mgL−1, indicating degradation efficiency higher than 99.24%. This value is comparable and in some cases higher than published data on the degradation in drinking water. Kinetic analysis of the data indicated an overall first-order reaction with a rate constant of 1.0594 min−1 at 20 °C. The reaction order differs with the second-order reaction observed by other researchers. This change of reaction order could be explained by the different treatment conditions used. Preliminary analysis using the FT-IR technique was also performed in order to obtain information on the structure of the degradation products. Further analysis using a GC-MS is needed in order to elucidate the structure of the degradation products. Finally, based on the experiments performed, ozonation seems to be a promising technique for the degradation of antibiotics, even in wastewater.

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Photodegradation of Bis(4-Hydroxyphenyl) Methane Based on the Inclusion of Two Cyclodextrins under Ultraviolet Irradiation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.665.575 ◽

2014 ◽

Vol 665 ◽

pp. 575-578

Author(s):

Ji Ping Yu ◽

Li Guo ◽

An Yun Yang ◽

Jian Xiang Li

Keyword(s):

Aqueous Solution ◽

Ultraviolet Irradiation ◽

Inclusion Complexation ◽

Reaction Model ◽

Order Reaction ◽

First Order ◽

Photodegradation Efficiency ◽

Cyclodextrin Inclusion ◽

Inclusion Interaction ◽

Kinetics Of

Photodegradation of bis (4-hydroxyphenyl) methane (BPE) was investigated under ultraviolet light (λ=254nm) based on the inclusion of two kinds cyclodextrin (α-CD, β-CD) in aqueous solution. The inclusion interaction of α-and β-cyclodextrin with BPE was characterized by fluorescence spectrophotometer. The addition of cyclodextrin could promote photodegradation efficiency of BPE, which the β-CD promoted the most. The kinetics of BPE photodegradation with different initial concentrations was investigated by first-order reaction model. Experiment results demonstrate that β-cyclodextrin inclusion complexation can accelerate BPE photodegradation in aqueous solution under ultraviolet irradiation.

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Modeling the kinetics of peroxidase inactivation, colour and texture changes of Portuguese cabbage (Brassica oleracea L. var. costata DC) during UV-C light and heat blanching

International Journal of Food Studies ◽

10.7455/ijfs.v5i2.346 ◽

2016 ◽

Vol 5 (2) ◽

Cited By ~ 1

Author(s):

Rui M.S. Cruz ◽

Ana I.A. Godinho ◽

Dilek Aslan ◽

Necip F. Koçak ◽

Margarida C. Vieira

Keyword(s):

Combined Treatment ◽

Reaction Model ◽

Order Reaction ◽

First Order ◽

Processing Times ◽

Texture Parameters ◽

Colour Changes ◽

Kinetics Of ◽

Uv C ◽

Brassica Oleracea L

The effects of heat blanching and UV-C light followed by heat on Portuguese cabbage peroxidase (POD), colour and texture were studied in the temperature range of 80-95 °C. POD inactivation, lightness (L) and yellowness (b) colour changes were described by a first-order reaction model. The greenness (a) colour and texture (firmness) changes followed a two fraction kinetic model behaviour. The temperature effect was well described by the Arrhenius law.At lower temperatures the combined treatment showed higher POD inactivation. Colour and texture parameters did not show significant differences between treatments. Long processing times turned the leaves slightly darker, decreased greenness, yellowness and firmness. Short processing times increased the firmness and greenness of the leaves. The treatment at 80 °C for 90 seconds reduced 90% of POD, retaining 98% of lightness and 92% of yellowness and improved the green colour (130%) and firmness (125%). At 80 °C the heat blanching required 7.4 min to inactivate 90% of the enzyme activity, reducing lightness, greenness, yellowness and firmness to 92%, 68%, 62% and 61%, respectively. The present findings will help to optimize the Portuguese cabbage blanching conditions.

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GASIFICATION STUDY OF SARAWAK COALS

ASEAN Journal on Science and Technology for Development ◽

10.29037/ajstd.232 ◽

2017 ◽

Vol 25 (1) ◽

pp. 67-72

Author(s):

Nor Fadzilah Othman ◽

Mohd Hariffin Bosrooh

Keyword(s):

Activation Energy ◽

Kinetic Parameters ◽

Arrhenius Equation ◽

Preliminary Investigation ◽

Reaction Model ◽

Order Reaction ◽

Low Rank ◽

Heating Rates ◽

First Order ◽

Air Atmosphere

Thermogravimetry (TG) has been applied in a preliminary investigation, to the gasification of two low rank Sarawak coals. The coal samples, about 10 mg were investigated within the temperature range 30–900°C at different heating rate of 10, 20 and 30°C min-1, under a synthetic air atmosphere for the gasification study. The kinetic parameters were determined using Arrhenius type reaction model assuming a first-order reaction. The reactivity, RT values are fitted with Arrhenius equation at r2 = 0.83 - 0.98 for MP coal, while the RT values for MB coal are fitted with the Arrhenius equation at r2 = 0.99. The activation energy, EA for MP coal are in the range of 3.7 -4.7 kJ mol-1 and for MB coal are 7.6 - 25.6 kJ mol-1 at 3 different heating rates.

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