Comparing the efficacy of catalytic ozonation and photocatalytical degradation of cyanide in industrial wastewater using ACF-TiO2: catalyst characterisation, degradation kinetics, and degradation mechanism

2020 ◽  
pp. 1-20 ◽  
Author(s):  
Zahra Goodarzvand Chegini ◽  
Amir Hessam Hassani ◽  
Ali Torabian ◽  
Seyed Mehdi Borghei
Keyword(s):  
Industrial Wastewater ◽  
Degradation Kinetics ◽  
Degradation Mechanism ◽  
Catalytic Ozonation ◽  
Tio2 Catalyst ◽  
Catalyst Characterisation

Thermal degradation kinetics of Opuntia Ficus Indica flour and talc-filled poly (lactic acid) hybrid biocomposites by TGA analysis

2021 ◽  
pp. 002199832110082
Author(s):  
Azzeddine Gharsallah ◽  
Abdelheq Layachi ◽  
Ali Louaer ◽  
Hamid Satha
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Degradation Mechanism ◽  
Melt Processing ◽  
Thermal Degradation Kinetics ◽  
Poly Lactic Acid ◽  
Opuntia Ficus Indica ◽  
Model Free

This paper reports the effect of lignocellulosic flour and talc powder on the thermal degradation behavior of poly (lactic acid) (PLA) by thermogravimetric analysis (TGA). Lignocellulosic flour was obtained by grinding Opuntia Ficus Indica cladodes. PLA/talc/ Opuntia Ficus Indica flour (OFI-F) biocomposites were prepared by melt processing and characterized using Wide-angle X-ray scattering (WAXS) and Scanning Electron Microscope (SEM). The thermal degradation of neat PLA and its biocomposites can be identified quantitatively by solid-state kinetics models. Thermal degradation results on biocomposites compared to neat PLA show that talc particles at 10 wt % into the PLA matrix have a minor impact on the thermal stability of biocomposites. Loading OFI-F and Talc/OFI-F mixture into the PLA matrix results in a decrease in the maximum degradation temperature, which means that the biocomposites have lower thermal stability. The activation energies (Ea) calculated by the Flynn Wall Ozawa (FWO) and Kissinger Akahira Sunose (KAS) model-free approaches and by model-fitting (Kissinger method and Coats-Redfern method) are in good agreement with one another. In addition, in this work, the degradation mechanism of biocomposites is proposed using Coats-Redfern and Criado methods.

Catalytic ozonation of iohexol with α-Fe0.9Mn0.1OOH in water: Efficiency, degradation mechanism and toxicity evaluation

2021 ◽  
Vol 402 ◽  
pp. 123574 ◽  
Author(s):  
Pengwei Yan ◽  
Zhonglin Chen ◽  
Shuyu Wang ◽  
Yanchi Zhou ◽  
Li Li ◽  
...  
Keyword(s):  
Degradation Mechanism ◽  
Catalytic Ozonation ◽  
Water Efficiency ◽  
Toxicity Evaluation

scholarly journals Optimization Parameters, Kinetics and Mechanism of Naproxen Removal by Catalytic Wet Peroxide Oxidation with a Hybrid Iron-Based Magnetic Catalyst

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 287 ◽  
Author(s):  
Ysabel Huaccallo-Aguilar ◽  
Silvia Álvarez-Torrellas ◽  
Marcos Larriba ◽  
V. Ismael Águeda ◽  
José Antonio Delgado ◽  
...  
Keyword(s):  
Degradation Kinetics ◽  
Degradation Mechanism ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Surface Model ◽  
Oh Radicals ◽  
Order Kinetic ◽  
Peroxide Oxidation ◽  
Wet Peroxide Oxidation ◽  
Catalytic Wet Peroxide Oxidation

This work presents a study of the assessment of the operating parameters of the catalytic wet peroxide oxidation (CWPO) of naproxen (NAP) using magnetite/multi-walled carbon nanotubes (Fe3O4/MWCNTs) as a catalyst. The effect of pH, temperature, and H2O2 dosage on CWPO process was evaluated by using the response surface model (RSM), allowing us to obtain an optimum NAP removal of 82% at the following operating conditions: pH = 5, T = 70 °C, [H2O2]0 = 1.5 mM, and [NAP]0 = 10.0 mg/L. Therefore, NAP degradation kinetics were revealed to follow a pseudo-second-order kinetic model, and an activation energy value of 4.75 kJ/mol was determined. Adsorption and using only H2O2 experiments, both considered as blank tests, showed no significant removal of the pollutant. Moreover, Fe3O4/MWCNTs material exhibited good recyclability along three consecutive cycles, finding an average NAP removal percentage close to 80% in each cycle of 3 h reaction time. In addition, the scavenging tests confirmed that the degradation of NAP was mainly governed by •OH radicals attack. Two reaction sequences were proposed for the degradation mechanism according to the detected byproducts. Finally, the versatility of the catalyst was evidenced in the treatment of different environmentally relevant aqueous matrices (wastewater treatment plant effluent (WWTP), surface water (SW), and a hospital wastewater (HW)) spiked with NAP, obtaining total organic carbon (TOC) removal efficiencies after 8 h in the following order: NAP-SW > NAP-HW > NAP-WWTP.

Catalytic ozonation for odour removal of high temperature alumina refinery condensate

2012 ◽  
Vol 66 (8) ◽  
pp. 1781-1786 ◽  
Author(s):  
Xinguang Wang ◽  
Jing Guan ◽  
Richard M. Stuetz
Keyword(s):  
Industrial Wastewater ◽  
Industrial Process ◽  
Catalytic Ozonation ◽  
Ozone Treatment ◽  
Experimental Conditions ◽  
Before And After ◽  
Removal Efficiencies ◽  
Odour Emissions ◽  
Odour Removal ◽  
Dynamic Olfactometry

Odour emissions from aluminium processing can cause an impact on local communities surrounding such facilities. Of particular concern is fugitive odours emitted from the handling and use of refinery condensate streams, particularly the digestion condensate. This study evaluated the application of using catalytic ozonation to treat alumina refinery condensate in order to remove the potential emission of odourous compounds from the industrial wastewater. The technical challenges in treating the alumina refinery condensate are the high pH and temperatures of the wastewater effluent (over 80 °C and pH above 10) due the industrial process. The odour removal efficiencies for different catalysts (FeCl3, MnO, and MnSO4) under experimental conditions in terms of controlled pH, temperature and ozone dosage were determined before and after ozone treatment using dynamic olfactometry. The result demonstrated that the addition of both FeCl3 and MnO catalysts improved odour removal efficiencies during the ozonation of alumina condensates at similar pH and temperature conditions. FeCl3 and MnO had similar enhancement for odour removal, however MnO was determined to be more appropriate than MnSO4 for odour removal due to the colouration of the treated condensate.

A study on simultaneous catalytic ozonation of Hg0 and NO using Mn–TiO2 catalyst at low flue gas temperatures

2018 ◽  
Vol 72 (6) ◽  
pp. 1347-1361 ◽  
Author(s):  
Ping Zhang ◽  
Wei-guo Pan ◽  
Rui-tang Guo ◽  
Shu-ming Liu ◽  
Ming-yuan Li ◽  
...  
Keyword(s):  
Flue Gas ◽  
Catalytic Ozonation ◽  
Tio2 Catalyst

scholarly journals Photodegradation of methotrexate in aqueous solution: degradation kinetics and identification of transformation products

2021 ◽  
Author(s):  
Anaïs Espinosa ◽  
Sylvie Nélieu ◽  
Pascale Lieben ◽  
Charles Skarbek ◽  
Raphaël Labruère ◽  
...  
Keyword(s):  
Glutamic Acid ◽  
Environmental Concern ◽  
Degradation Kinetics ◽  
Degradation Mechanism ◽  
Parent Compound ◽  
Drinking Water Treatment ◽  
Transformation Products ◽  
Quantum Yields ◽  
Acid Oxidation ◽  
Ionization State

Abstract Methotrexate is an antineoplastic folate analog of high environmental concern, due to its low biodegradability and toxicological properties. This study focused on its photodegradation under two irradiation conditions, aiming to be representative of environment (300–450 nm) and drinking water treatment (254 nm). The photodegradation experiments were conducted at two pH, to vary the methotrexate ionization state and to produce a large variety of transformation products (TPs). The degradation kinetics determined through LC-UV monitoring were contrasted according to pH and irradiation wavelength. However, the quantum yields were independent of ionization state at 254 nm and the changes in kinetics at higher wavelengths were attributed to a change in the degradation mechanism. The TPs formed during the reactions were identified by UHPLC-MS/MS, using both the positive and negative modes. Among the eleven proposed structures, five were described as methotrexate TPs for the first time. The TPs result from N-demethylation, glutamic acid oxidation and C-N cleavage, all of them leading to further degraded photoproducts presenting modified or lost glutamic acid part. This was made possible thanks to the negative mode, which allowed the exploration of the glutamic acid moiety modifications. Cytotoxicity assessment on A549 cancer cells demonstrated that all photoproducts formed at pH 7 were less toxic than the parent compound.

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