Catalytic Oxidation Process and Thermal Characteristics of Toluene and Butyl Acetate Vapor in an Oven

Wet air oxidation (WAO) is an established technique for reducing the chemical oxygen demand (COD) of refinery sulfidic spent caustic waste. In the present work, the heterogeneous form of the cheap and abundant catalyst ferrous sulfate (FeSO4) was employed for WAO of sodium sulfide. The performance of this catalyst in the oxidative destruction of this model compound is thus far unfamiliar. Kinetic data for the non‐catalytic and catalytic oxidation processes was collected in a batch reactor. For the catalytic process, temperature (T), oxygen partial pressure () and catalyst concentration (ω) were varied in the ranges 80‐150°C, 0.69‐2.06 MPa and 0.8‐2.4 g/L respectively. Around 94% COD was destroyed within 1 h when feed containing 8 g/L of sulfide was oxidized at T = 100°C, = 0.69 MPa, and ω = 0.8 g/L. First, the data on disappearance of COD were fitted to a power law model and reaction rate constants were determined. The activation energy for the non‐catalytic (91 kJ/mol) and catalytic (50 kJ/mol) oxidation process was found from the temperature dependence of the rate constants. Second, hyperbolic models based on Langmuir‐Hinshelwood (L‐H) and Eley‐Rideal (E‐L) kinetics were used for fitting kinetic data. It was found that the L‐H model suggesting dissociative adsorption of oxygen provided the best fit. In this way, a deep insight into oxidation kinetics of sodium sulfide was provided.

The influence of the catalyst on the CO formation during catalytic wet peroxide oxidation process

Treatment of phenol wastewater by microwave-induced ClO 2-CuO x/Al 2O 3 catalytic oxidation process

Oxytetracycline degradation and toxicity evolution by catalytic oxidation process over sludge derived carbon

Singlet oxygen (1O2) plays a pivotal role in numerous catalytic oxidation processes utilized in water purification and chemical synthesis. The spin-trapping method based on electron paramagnetic resonance (EPR) analysis is commonly employed for 1O2 detection. However, it is often limited to time-independent acquisition. Recent studies have raised questions about the reliability of the 1O2 trapper, 2,2,6,6-tetramethylpiperidine (TEMP), in various systems. In this study, we introduce a comprehensive, kinetic examination to monitor the spin-trapping process in EPR analysis. The EPR intensity of the trapping product was used as a quantitative measurement to evaluate the concentration of 1O2 in aqueous systems. This in situ kinetic study was successfully applied to a classical photocatalytic system with exceptional accuracy. Furthermore, we demonstrated the feasibility of our approach in more intricate 1O2-driven catalytic oxidation processes for water decontamination and elucidated the molecular mechanism of direct TEMP oxidation. This method can avoid the false-positive results associated with the conventional 2D 1O2 detection techniques, and provide insights into the reaction mechanisms in 1O2-dominated catalytic oxidation processes. This work underscores the necessity of kinetic studies for spin-trapping EPR analysis, presenting an avenue for a comprehensive exploration of the mechanisms governing catalytic oxidation processes.

The system design of atrazine oxidation by catalytic oxidation process through a kinetic approach

The effect of deposit morphology on soot oxidation in non-catalytic and catalytic processes

Desulfurization of heavy naphtha by a catalytic oxidation process combining hydrogen peroxide with organic and inorganic acids and in the presence of a PMN550 catalyst. This study was conducted to find out the effect of many variables on the efficiency of the process, especially the effect of hydrogen peroxide, the amount of acid, temperature, residence time, weight of the catalyst (0.01-0.6) g, temperature (20-120) C, residence time (20-140) minutes, ratio hydrogen peroxide to heavy naphtha (0.1-0.6) ml and ratio acid to heavy naphtha (0.01-0.175) ml. The catalytic oxidation process depends on all of the above variables. Desulphurization of heavy naphtha using organic and inorganic oxidizers in combination with hydrogen peroxide, glacial acetic acid, phthalic acid, malic acid, sulfuric acid and formic acid. The maximum removal of sulfur was with sulfuric acid and formic acid, which are 50%, 55%, respectively. the catalytic oxidation process carried out In two steps: the first step was the catalytic oxidation at a moderate temperature and atmospheric pressure, and the second step was to extract the oxidized mixture with a methanol-water mixture. The efficiency of the catalytic oxidation process carried out in the presence of PMN550 reached 99%. The catalyst was manufactured in the laboratory and a set of catalyst tests were performed on it FT-IR, AFM, BET, XRD, and XRF, which It has proven its efficacy. Mathematical models of the relevant reactions were developed to match the experimental results by obtaining the optimal kinetic parameters. Using optimization methods, the maximum conversion rate was 99%, at a temperature of 90°C, a residence time 60 minutes and the initial concentration was 651.3ppm.

Dyes are used in various industries as coloring agents. The discharge of dyes, specifically synthetic dyes, in wastewater represents a serious environmental problem and causes public health concerns. The implementation of regulations for wastewater discharge has forced research towards either the development of new processes or the improvement of available techniques to attain efficient degradation of dyes. Catalytic oxidation is one of the advanced oxidation processes (AOPs), based on the active radicals produced during the reaction in the presence of a catalyst. This paper reviews the problems of dyes and hydroxyl radical-based oxidation processes, including Fenton’s process, non-iron metal catalysts, and the application of thin metal catalyst-coated tubular reactors in detail. In addition, the sulfate radical-based catalytic oxidation technique has also been described. This study also includes the effects of various operating parameters such as pH, temperature, the concentration of the oxidant, the initial concentration of dyes, and reaction time on the catalytic decomposition of dyes. Moreover, this paper analyzes the recent studies on catalytic oxidation processes. From the present study, it can be concluded that catalytic oxidation processes are very active and environmentally friendly methods for dye removal.

Determination and toxicity evaluation of the generated byproducts from sulfamethazine degradation during catalytic oxidation process

Degradation of remazol golden yellow dye wastewater in microwave enhanced ClO 2 catalytic oxidation process

Study on the treatment of 2- sec-butyl-4,6-dinitrophenol (DNBP) wastewater by ClO 2 in the presence of aluminum oxide as catalyst

The CO catalytic oxidation process on the surface of Fe-N3 co-doped graphyne was systematically investigated using first-principles calculations combined with the climbing-image nudged elastic band (CI-NEB) method. The Y-shaped FeN3 active sites on the graphyne surface were constructed by forming stable N-C covalent bonds between three N atoms and their adjacent C atoms and by establishing coordination between the transition metal Fe atom and three N atoms. CO and O2 molecules were chemisorbed on the doped surface through the formation of Fe-C and Fe-O bonds with the FeN3 active sites, with the C1 configuration surface exhibiting a stronger adsorption capacity toward the gas molecules. Comparative analysis of the kinetic behaviors of CO catalytic oxidation under three distinct reaction mechanisms, Eley-Rideal (ER), Langmuir-Hinshelwood (LH), and termolecular Eley-Rideal (TER), revealed that CO molecules preferentially undergo oxidation along the ER1 pathway on the FeN3-doped graphyne surface. The rate-determining step (RDS) energy barriers are 0.409 and 0.002 eV, respectively, with substantial heat released during the reaction process. Following the desorption of CO2 via the ER1 pathway, the remaining O atom on the doped surface can further react with another CO molecule at low energy barriers (0.066 eV for C1 and 0.016 eV for C2) to form a second CO2 molecule, indicating that the catalytic activity of the doped substrate can be fully restored. Owing to the moderate adsorption strength for CO molecules on the C2 surface with an adsorption energy of -1.108 eV, the catalytic oxidation process along the TER pathway presents distinct advantages over several noble-metal catalysts and transition-metal-doped two-dimensional material catalysts. The energy barrier of the RDS is only 0.609 eV, and the reaction proceeds with continuous heat release. Therefore, modifying the graphyne surface via Fe-N3 coordination doping may provide a new perspective for the design of graphyne-based single-atom catalysts.

A chamber study of catalytic oxidation of SO2 by Mn2+/Fe3+ in aerosol water

Advanced oxidation removal of hypophosphite by O3/H2O2 combined with sequential Fe(II) catalytic process