scholarly journals Simultaneous biodegradation of dimethyl sulfide and 1-propanethiol by Pseudomonas putida S-1 and Alcaligenes sp. SY1: “Lag” cause, reduction and kinetics exploration

2021 ◽  
Author(s):  
Qian Li ◽  
Zeqin Tang ◽  
Jiahui Zhang ◽  
Jingtao Hu ◽  
Jianmeng Chen ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Dimethyl Sulfide ◽  
Gompertz Model ◽  
Lag Phase ◽  
Mechanism Analysis ◽  
Order Model ◽  
First Order ◽  
Negative Effect ◽  
Pseudo First Order ◽  
Modified Gompertz Model

Abstract Simultaneous biodegradation of malodorous 1-propanethiol (PT) and dimethyl sulfide (DMS) inoculated with Pseudomonas putida S-1 and Alcaligenes sp. SY1 were investigated and interactions implicated were explored. Results showed that PT was completely degraded in 33 h, while a lag of 10 h was observed for DMS degradation alone, and the lag even extended to 81 h in the binary mixture. Mechanism analysis found that the lag was mainly attributed to the exposure of DMS degrader (Alcaligenes sp. SY1), rather than PT metabolites and PT degrader. The exposure time and PT concentration influenced the lag duration much. Citric acid could effectively reduce the lag. Pseudo first-order model was proved suitable for the description of PT degradation, revealing that PT degradation could be enhanced in presence of DMS regardless of its concentration. A modified Gompertz model, incorporated the lag phase, was developed for the description of DMS degradation in the mixture, revealing that DMS degradation depended on the initial PT concentration. When the lag was not considered, PT with low-concentration could promote DMS biodegradation, while a higher concentration (＞20 mg·L−1) cast negative effect.

Kinetic study of dye removal using TiO2 supported on polyethylene terephthalate by advanced oxidation processes through neural networks

2019 ◽  
Vol 79 (6) ◽  
pp. 1134-1143 ◽  
Author(s):  
Ada Azevedo Barbosa ◽  
Ramon Vinicius Santos de Aquino ◽  
Naiana Santos da Cruz Santana Neves ◽  
Renato Falcão Dantas ◽  
Marta Maria Menezes Bezerra Duarte ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Polyethylene Terephthalate ◽  
Advanced Oxidation Processes ◽  
Dye Removal ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Order Model ◽  
Oxidation Processes ◽  
First Order ◽  
Pseudo First Order

Abstract This work investigated the efficiency of polyethylene terephthalate (PET) as support material for TiO2 films in the photocatalytic degradation of red Bordeaux and yellow tartrazine dyes. The optimum operating conditions were determined by a factorial design, which resulted after 180 min of treatment in degradations of 99.5% and 99.1% for the UVC/H2O2/TiO2Sup and solar/H2O2/TiO2Sup systems, respectively. For the kinetic study, the experimental data fitted to the pseudo-first-order model and the calculated kinetic constants (k) values were 0.03 min−1 for the UVC/H2O2/TiO2Sup system and 0.0213 min−1 for the system solar/H2O2/TiO2Sup. It was verified that TiO2 supported in the PET remained with high degradation efficiency even after five cycles of reuse, indicating a good stability of the photocatalyst in the support. A significant reduction of TOC content was also observed along the reaction time. The phytotoxicity bioassay with Lactuca sativa demonstrated that after treatment with UVC/H2O2/TiO2Sup and solar/H2O2/TiO2SUP, an increase in IC50 and consequently lower toxicity was observed.

scholarly journals Isotherm, Thermodynamic, and Kinetics Studies of Iodide Adsorption on The Al_SBA-16 Mesoporous Nanomaterial as Radiopharmaceutical Vehicle Candidate

2020 ◽  
Vol 21 (1) ◽  
pp. 27
Author(s):  
Maria Christina Prihatiningsih ◽  
Sri Sundari Retnoasih ◽  
Athanasia Elra Andjioe ◽  
Noor Anis Kundari ◽  
Edy Giri Rachman Putra
Keyword(s):  
Activation Energy ◽  
Hypothesis Testing ◽  
Research Work ◽  
P Value ◽  
Testing Time ◽  
Order Model ◽  
First Order ◽  
Pseudo First Order ◽  
In Vitro Stability

In order to investigate the potential of Al_SBA-16 Mesoporous Nanomaterial as a candidate for radiopharmaceutical vehicles, the studies of kinetics, thermodynamic, and in vitro stability of Iodide adsorption onto the nanomaterial have been carried out. The adsorption study was conducted at different temperature, time, and iodide concentration and observed with spectrophotometric techniques. The isotherm adsorption was fitted with Langmuir and Freundlich model and the thermodynamic parameters were determined at temperatures of 293K, 301K, 308K, and 313K. Moreover, the adsorption kinetics was analyzed in terms of pseudo first order model for Al_SBA-16 Mesoporous Nanomaterial and Iodide and pseudo second order in overall reaction. The activation energy was determined by using Arrhenius equation, meanwhile, the in vitro stability testing was conducted in phosphate buffer saline at pH variation for 5.5 to 7.0, and at temperature variation for 20C to 45C and at testing time variation for 6 to 48 hours. The result indicate that the adsorption obeys the Langmuir isotherm model and has a tendency to be chemical adsorption with a value of H was -116.641 kJ/mol and the nature of spontaneous reactions. The adsorption process followed the pseudo-first-order model and the apparent activation energy was 41.26 kJ/mol. In the present research work, the in vitro stability data were evaluated using P-Value and the theory of Hypothesis Testing or Fisher's significance test. The result of hypothesis testing show that, the adsorption of iodide onto Al_SBA-16 Mesoporous Nanomaterial were highly stable under the experimental conditions adopted.

An evaluation of the Gompertz model in degradability studies of forage chemical components

1997 ◽  
Vol 64 (3) ◽  
pp. 423-431 ◽  
Author(s):  
A. Lavrenčič ◽  
B. Stefanon ◽  
P. Susmel
Keyword(s):  
Lignin Content ◽  
Correlation Coefficients ◽  
Gompertz Model ◽  
Chemical Components ◽  
Order Model ◽  
Mean Values ◽  
First Order ◽  
Total Potential ◽  
Model Average ◽  
Significant Difference

AbstractThe in situ dry matter (DM) and neutral-detergent fibre (NDF) degradability kinetics of eight forages (four grass hays and four legume hays, harvested at two different dates) were compared to assess the fitting ability of a first-order and a Gompertz model.The Gompertz model fitted DM degradability data as well as the first-order model and differences between fitted and observed data for the two models were very small but the Gompertz model proved to be statistically superior for the NDF degradability data, especially for the early hours of incubation.A numerical but not significant difference was observed in the estimated rapidly available fraction for DM and NDF, which zvas respectively lower (mean values 24·4 v. 27·8%) and higher (mean values 5·8 v. 1·8%) with the first-order model. More pronounced differences were observed for the estimates of total potential degradability of NDF, which were often significantly lower with the Gompertz model (average values for the eight forages 75·1 v. 72·3%;.The sigmoidal shape of the Gompertz model was more biologically appropriate to describe the initial phases of NDF degradation and was thus applied to the cellulose and hemicellulose degradability data.As the harvesting date progressed through the season, a decrease of the immediately available fraction of DM and nitrogen was generally observed but the effect of harvesting date was not so evident for fibre fractions; the differences within forages were very low. Correlation coefficients between lignin content and total potential degradability of fibre were always high (for NDF, r = −0·96; for hemicellulose r = −0·95; for cellulose r = −0·79; P < 0·001), while the acid-detergent fibre content influenced DM and nitrogen total potential degradability (r = −0·91 and −0·82, respectively).

Rice Husk Active Carbon as a Potential Low-Cost Adsorbent for TNT Wastewater

2011 ◽  
Vol 356-360 ◽  
pp. 1289-1292
Author(s):  
Dan Fu ◽  
Yi He Zhang ◽  
He Li Wang ◽  
Feng Zhu Lv
Keyword(s):  
Rice Husk ◽  
Active Carbon ◽  
Low Cost ◽  
Adsorption Properties ◽  
Second Order ◽  
Order Model ◽  
First Order ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
And Diffusion

In this paper, the adsorption properties of TNT on Rice husk active carbon (RHAC) were investigated. The effects of contact time was examined. Kinetic data obtained at different concentrations were conducted using Lagergren’s pseudo first-order, pseudo second-order and diffusion models. The regression results showed that the adsorption kinetics was more accurately represented by pseudo second-order model. The study indicates that there is significant potential for RHAC as an adsorbent material for TNT removal from wastewater.

scholarly journals The Application of Monkey Cola Pericarp (Cola lepidota) in the Removal of Toluene from Aqueous Medium

2020 ◽  
pp. 53-67
Author(s):  
C. Obi ◽  
N. C. Ngobiri ◽  
L. C. Agbaka ◽  
M. U. Ibezim-Ezeani
Keyword(s):  
Aqueous Medium ◽  
Contact Time ◽  
Second Order ◽  
Phytochemical Screening ◽  
Order Model ◽  
Initial Concentration ◽  
First Order ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Pseudo First Order

The study focused on the investigation of the effectiveness of the pericarp of monkey kola (Cola lepidota) biomass (CLPB) in the removal of toluene from aqueous system. X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and phytochemical screening methods were used for characterizing the biosorbent. The effects of contact time, pH, and concentration on biosorption process were studied. The phytochemical screening showed the presence of alkaloids, flavonoids, tannins, carbohydrate, saponins and steroids. Carboxylic, alkene and alcohol groups were found to be the principal functional groups. The highest percentage removal was 99.63% at toluene initial concentration of 40 mg/L and 98.30% at pH 8. The contact time 30 minutes gave better removal efficiency of 99.89%. Among the biosorption isotherm models tested (Langmuir, Freundlich, Dubinin Radushkevich and Temkin, respectively), the Langmuir model equation gave a better fit of the equilibrium data with a correlation coefficient (R2) of 0.99. The equilibrium data was tested with pseudo-first order and pseudo-second order models and pseudo-second order model (R² = 0.99) fitted more than the pseudo-first order model (R² = 0.85). This study has revealed that Cola lepidota is a potential biosorbent for the removal of toluene from aqueous medium under the operating conditions of contact time of 30 minutes, pH of 8 and initial concentration of 40 mg/g.

scholarly journals Kinetic study on the removal of heavy metals by Cajanus Cajan husk

2019 ◽  
pp. 206-229
Author(s):  
Mallappa A. Mallappa A. Devania, Mallappa A. Devania ◽  
Basudeb Munshi
Keyword(s):  
Heavy Metals ◽  
Kinetic Model ◽  
Kinetic Models ◽  
Cajanus Cajan ◽  
Second Order ◽  
Order Model ◽  
First Order ◽  
Removal Of Heavy Metals ◽  
Pseudo Second Order ◽  
Pseudo First Order

The removal of heavy metals from wastewater has become crucial to meet safe discharge standards. Development of more economic process has been strived owing to high cost of adsorbents. Thus, biosorption process has become the area of interest to researchers and engineers. The present study has carried out the transient removal of heavy metals from wastewater by both physically treated and chemically modified Cajanus cajan (Pigeon pea) husk (CCH) as novel biosorbents. Work includes five different models such as first order, second order, nth order, first order reversible and second order reversible under the heading of prediction of transient concentration of metal in the solution are used, and under the heading of prediction of transient metal uptake capacity; fractional power, pseudo first order, pseudo second order, second order reversible, Elovich, intra-particle diffusion and film diffusion models are used to analyse the kinetic data. For a metal at any particular initial concentration the best kinetic model with the least RMSE is identified. Pictorial comparison between experimental and pseudo second order and pseudo first order model predictive data of Cd(II) and Cu(II) transient biosorption, respectively onto CCH are illustrated. The trend of the results shows a successful prediction capability of all the kinetic models used in the present work. According to RMSE data, it can be concluded that the best kinetic models are pseudo second order for Cd(II) and pseudo first order for Cu(II). It has been found that the required equilibrium time is always less for the chemically activated than the physically activated sorbent. At 100 mg/L initial metal concentration, pseudo-first-order model has been identified as the best kinetic model for the transient Cu(II) and the best kinetic model for fitting the transient sorption of Cd(II) on CCH is pseudo-second-order. At initial metal concentration of 150 mg/L, initial biosorption rate of 9.7038 for Cd(II) on CCH(N) is greater than 1.4553 for Cu(II) on CCH(N). These indicate that Cd(II) undergoes faster adsorption rate than Cu(II) onto CCH.

Water Treatment Combined Chlorine (Monochloramine) Degradation using Direct Photolysis and Homogeneous Photocatalysis (UV/H2O2, UV/NaOCl) with a Medium Pressure (MP) Lamp as a Source of UV

2014 ◽  
Vol 12 (2) ◽  
pp. 671-681 ◽  
Author(s):  
Ala Abdessemed ◽  
Kamel E. Djebbar ◽  
Amer S. El-Kalliny ◽  
T. Sehili ◽  
Henk Nugteren ◽  
...  
Keyword(s):  
Oh Radicals ◽  
Order Model ◽  
Direct Photolysis ◽  
First Order ◽  
Medium Pressure ◽  
Pseudo First Order ◽  
Homogeneous Photocatalysis ◽  
Photochemical Systems ◽  
Nitrite Nitrate ◽  
The Given

Abstract The objective of this study is to investigate the use of photochemical systems (photolysis, H2O2/UVMP and NaOCl/UVMP) to deplete monochloramine compound with a medium pressure lamp as an irradiation source (200–600 nm). First, it was found that the direct photolysis treatment was a suitable method to degrade the given compound and that this degradation was greatly enhanced by H2O2/UVMP. This could be attributed to radical •OH produced in great amount by the photolysis of H2O2. However, no big advantages were observed when we used NaOCl/UVMP system. Indeed, this process generated radical •OH (but in feeble amount) and also radical Cl• (to form chloramins) and leading consequently to a less degradation rate comparatively to that obtained with H2O2/UVMP. This could be explained by a competition between the two species: •OH and Cl• for the compound. In addition, kinetics data for the three systems were best represented by a pseudo-first-order model and the photodecomposition of NH2Cl has led to the formation of nitrite, nitrate without forming ammonia.It is essential to mention that •OH radicals produced from H2O2/UVMP and NaOCl/UVMP was detected by a photoluminescence (PL) technic using terephthalic acid (TA) as a probe molecule.

Evaluation of Chlorine for Inactivation of Bioterrorism Agents in Drinking Water

2013 ◽  
Vol 295-298 ◽  
pp. 599-603
Author(s):  
Feng Liu ◽  
Zhong Lin Chen ◽  
Sheng Chang
Keyword(s):  
Drinking Water ◽  
Free Chlorine ◽  
Inactivation Kinetics ◽  
Lag Phase ◽  
Solution Ph ◽  
First Order ◽  
Pseudo First Order ◽  
Ph Range ◽  
Kinetics Of ◽  
Experimental Temperature Range

The object of this paper is to measure the characteristics of the inactivation kinetics of B. subtilis spores-surrogates for B. anthracis spores following the treatment with free chlorine. The results indicated that the inactivation kinetics of B. subtilis spores with free chlorine was characterized by a lag phase followed by a pseudo-first-order rate of inactivation. The magnitude of the lag phase increased and the rate of subsequent inactivation decreased with the decreasing temperature, for the experimental temperature range of 1-30 °C. The same tendency of inactivation kinetics curves was observed for the increasing solution pH, for the experimental pH range of 6-8. The CT concept was proved to be valid for the inactivation kinetics of B. subtilis spores with free chlorine under the conditions investigated. The validity of B. subtilis spores served as conservative surrogates for B. anthracis spore has been finally discussed.

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