Products and mechanism of thermal decomposition of chlorpyrifos under inert and oxidative conditions

Weber, Nathan H.; Stockenhuber, Sebastian P.; Benhelal, Emad; Grimison, Charles; Lucas, John; Mackie, John C.; Stockenhuber, Michael; Kennedy, Eric M.

doi:10.1039/d0em00295j

Cited by 9 publications

(12 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A solvent (dichloromethane, ChemSupply, Australia, >99.9%) liquid trap was also used for liquid product analysis using an Agilent GC 6890 MS 5973N (an HP-5MS column of 30 m × 0.25 mm). A similar experimental procedure can be found in our previous publication . For further information on the GC methodology used, refer to the Supporting Information.…”

Section: Experimental Methodologymentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of Decomposition of PFOS Relevant to Thermal Desorption Remediation of Soils

Weber

Stockenhuber

Delva

et al. 2021

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

Kinetics of pyrolysis of the pollutant perfluorooctanesulfonic acid (PFOS) in inert bath gases have been studied in two flow reactors constructed of α-alumina and of stainless steel (SS) at temperatures between 400 and 615 °C. Results from the SS reactor give support to previous and our own quantum chemical calculations based on smaller perfluorinated sulfonates, according to which initiation of decomposition of PFOS first takes place by elimination of HF to form an unstable α-sultone with a rate constant, k 1 . The sultone then rapidly liberates SO 2 and forms perfluorooctanoyl fluoride with a rate constant, k 2 with k 2 ≫ k 1 such that the overall rate constant k′ ≈ k 1 . Products observed from both reactors in the above temperature range comprised HF, SO 2 , and perfluorooctanoyl fluoride. The value of the rate constant for the formation of HF and SO 2 measured in the SS reactor was found to be k 1 = (1.3 ± 0.5) × 10 14 exp(−253 ± 5 kJ/mol/RT) s −1 .

show abstract

Section: Experimental Methodologymentioning

confidence: 99%

“…A similar experimental procedure can be found in our previous publication. 23 For further information on the GC methodology used, refer to the Supporting Information.…”

Section: ■ Experimental Methodologymentioning

confidence: 99%

Kinetics of Decomposition of PFOS Relevant to Thermal Desorption Remediation of Soils

Weber

Stockenhuber

Delva

et al. 2021

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

show abstract

“…A more detailed experimental procedure is provided in our previous work. 24,27 Quantitative Analysis. For quantitative analysis of the thermal decomposition of PFOS, the reactor furnace was operated in a linear heating mode with a 5 °C min −1 heating rate.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Modeling and Experimental Study on the Thermal Decomposition of Perfluorooctanesulfonic Acid (PFOS) in an α-Alumina Reactor

Weber

Delva

Stockenhuber

et al. 2022

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

Pyrolysis of perfluorooctanesulfonic acid (PFOS) (200−450 PPMV) was studied in an α-alumina flow reactor under plug flow conditions at temperatures from 450 to 1000 °C and helium flow velocities of 100, 200, and 300 mL min −1 . Major products at the lowest temperatures were HF, SO 2 , and perfluorooctanyl fluoride (C 8 F 16 O). A new low-temperature product, C 2 F 4 , was detected in significant quantities from the decomposition of PFOS. The pyrolysis mechanism was studied by quantum chemical calculation at the b3lyp/GTLarge//b3lyp/6-31G(d,p) and G4MP2 levels of theory to develop a thermochemical analysis and preliminary chemical kinetic model for the decomposition. Alongside the previously postulated initiation of pyrolysis via an α-sultone intermediate to C 8 F 16 O, we have discovered a competitive direct fission route for PFOS into C 8 F 17 radicals and HOSO 2 . C 8 F 17 rapidly fissions CF 2 radicals, which are the source of the observed C 2 F 4 . At the lowest temperatures, an acceleration in the rates of production of C 2 F 4 , HF, and SO 2 was observed in the α-alumina reactor when compared with predictions of the kinetic model. An alumina nanocluster was subjected to quantum chemical analysis to show that PFOS can be both chemisorbed and physisorbed on an alumina surface, a process that might explain the experimental observation of an acceleration of decomposition in an α-alumina reactor at low temperatures.

show abstract

“…According to Salama et al ., the decomposition of AMS occurs in two different steps with a first mass loss (C 9 H 12 SO 3 N molecule) in the temperature range 202–390 °C and a second loss (C 6 H 12 N and CH 3 NO) in the temperature range 393.41–726.86 °C 53 . Furthermore, carbamazepine and amitriptyline require decomposition temperatures higher than 377 °C and 270 °C, respectively, 54,55 while thermal decomposition of chlorpyrifos under inert and oxidative conditions was achieved at temperatures higher than 550 °C 56 . Thus, runs 4, 10 and 13, with lower reaction temperatures and time, exhibited decreased removal rates (64.79%, 66% and 55.79%, respectively) compared to runs 2, 3 and 6 employing higher temperatures and decomposition efficiencies (79.1%, 83.11% and 88.63%, respectively).…”

Section: Resultsmentioning

confidence: 99%

“…53 Furthermore, carbamazepine and amitriptyline require decomposition temperatures higher than 377 °C and 270 °C, respectively, 54,55 while thermal decomposition of chlorpyrifos under inert and oxidative conditions was achieved at temperatures higher than 550 °C. 56 Thus, runs 4, 10 and 13, with lower reaction temperatures and time, exhibited decreased removal rates (64.79%, 66% and 55.79%, respectively) compared to runs 2, 3 and 6 employing higher temperatures and decomposition efficiencies (79.1%, 83.11% and 88.63%, respectively). Furthermore, autogenic pressure in co-presence with temperature can change the properties of water affecting the degradation of pollutants.…”

Section: Fate Of Organic Pollutants During Htcmentioning

confidence: 87%

Removal of organic pollutants (pharmaceuticals and pesticides) from sewage sludge by hydrothermal carbonization using response surface methodology (RSM)

Miserli

Nastopoulou

Konstantinou

2022

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

BACKGROUND Conventional wastewater treatment plants (WWTPs) cannot degrade completely emerging pollutants such as pharmaceuticals and pesticides. The release of such contaminants through WWTP effluents or sludge disposal is of high environmental concern. Hydrothermal treatment has been adopted as alternative treatment technology for sludge to recover energy and valuable products. This study demonstrates the removal of inherent concentration levels of organic pollutants from the previous classes under variable reaction conditions, i.e. temperature, reaction time and sludge‐to‐water (%wt) ratio. RESULTS Response surface methodology (RSM) was applied to model removal efficiency for the sum of detected pharmaceutical compounds and to evaluate the significant operational parameters. The results showed that higher values of temperature and time enhanced the percent degradation efficiency while sludge‐to‐water (%wt) ratio was not a significant factor affecting the removal process. The maximum removal efficiency of pharmaceutical residues reached 89.8% under the following conditions: 220 °C, 360 min reaction time, 7.50%wt sludge‐to‐water ratio. Additionally, hydrothermal treatment removed completely trace levels of detected pesticides, regardless of the applied conditions. RSM was also applied separately to those pharmaceuticals (i.e., amisulpride and amitriptyline) detected most frequently and at higher concentrations in sludge samples. Both compounds have been degraded at >90% using reaction temperatures from 205 to 220 °C and reaction time between 297 and 360 min with 7.5% sludge/H2O ratio. CONCLUSION Hydrothermal treatment is a suitable and promising technology for sewage sludge treatment for the efficient destruction of organic pollutants and the production of renewable hydrochars. © 2022 Society of Chemical Industry (SCI).

show abstract

Products and mechanism of thermal decomposition of chlorpyrifos under inert and oxidative conditions

Abstract: Chlorpyrifos (CPF) is a widely used pesticide; however, limited experimental work has been completed on its thermal decomposition. CPF is known to decompose into 3,5,6-trichloro-2-pyridinol (TCpyol) together with ethylene and...

Cited by 9 publications

References 30 publications

Kinetics of Decomposition of PFOS Relevant to Thermal Desorption Remediation of Soils

Kinetics of Decomposition of PFOS Relevant to Thermal Desorption Remediation of Soils

Modeling and Experimental Study on the Thermal Decomposition of Perfluorooctanesulfonic Acid (PFOS) in an α-Alumina Reactor

Removal of organic pollutants (pharmaceuticals and pesticides) from sewage sludge by hydrothermal carbonization using response surface methodology (RSM)

Contact Info

Product

Resources

About