Catalytic Oxidation Of Carbon Research Articles

Fluidized Immobilized Carbon Catalytic Oxidation Reactor for Treating Domestic Wastewater.

Treating wastewater and reusing it have become normal in the present era since the scarcity of fresh water prevails in many parts of the world. There are numerous techniques for treating domestic wastewater, and many have been explored to advance the ones already in use. This study is taken up to explore the new technology called fluidized immobilized carbon catalytic oxidation (FICCO). Usually, both organic and inorganic materials are present in residential wastewater. In this study, catalyst-activated carbon produced from rice husk is added to a FICCO reactor to test the effectiveness of decreasing organic contaminants in wastewater. Six FICCO models were fabricated in this research study, and tests were conducted. The effectiveness of COD and BOD removal was investigated using six FICCO models with activated carbon made from rice husk as a catalyst and presented in this paper. The FICCO reactor was also used to treat organic contaminants such as surfactants, starch, oil, and protein with rice husk as activated carbon as a catalyst. Organic pollutants used the FICCO reactor; COD removal varied from 75.6% to 92.4%, BOD removal ranged from 74.9% to 89.5% at the optimum contact time, and catalyst rice husk-activated carbon application. The optimum catalyst dosage was 12 g per 620 ml of wastewater, which is the capacity of each reactor and a substantial reduction in sludge.

Sequential combination of NaClO chain breakage/CuxO catalytic oxidation processes for high efficiency treatment of ultra-high concentration PVA wastewater

Polyvinyl alcohol (PVA) is a kind of refractory organic polymer with high COD and low BOD. Efficient treatment of PVA wastewater has always been a challenging subject especially for ultra-high concentration (UHC). In this paper, based on our previous work, a sequential combination process method including NaClO chain breakage followed by CuxO activated carbon catalytic oxidation was developed to efficient treat UHC PVA wastewater. The sequential combination system was optimized by monitoring the treatment performance with different key parameters (such as oxidant dosage, Cu loading and catalyst dosage, two-stage reaction time, pH value, etc.). And the COD of PVA wastewater declined from the initial 206,240.00 mg/L to 557.78 mg/L (removal rate 99.73 %), the PVA concentration decreased from the initial 171,325.00 mg/L to 19.94 mg/L (removal rate 99.99 %) under the optimal conditions. Through the discussion of the combined processes, it was found that both chain breakage and catalytic oxidation were necessary and indispensable to achieve efficient degradation of PVA wastewater. Additionally, the free radical scavenging experiments show that the combined oxidation process was mainly controlled by the catalytic oxidation process, and followed the free radical reaction mechanism with·OH as the main oxidant. Based on this, it is recommended that subsequent researchers focus on the combined process for the treat of refractory organic wastewater.

Synchronous COD removal and nitrogen recovery from high concentrated pharmaceutical wastewater by an integrated chemo-biocatalytic reactor systems

Present report, an investigation of highly concentrated and low bio-degradable pharmaceutical wastewater (HCPWW) treatment; simultaneously ammoniacal nitrogen recovery for struvite fertilizer. The use of multiple solvents and many formulation processes in HCPWW, resulting highly refractory chemicals. Here, in this study focused on evaluation of chemo-biocatalysts for the removal of refractory organics, nitrogen recovery from HCPWW. The initial organics, and nitrogen content in HCPWW was 20,753 ± 4606 mg/L; BOD, 6550 ± 1500 mg/L and NH4+-N, 1057.9 ± 185.8 mg/L. Initially, the biodegradability (BOD5: COD ratio from 0.32 to 0.45) of HCPWW, which was improved by heterogeneous Fenton oxidation (HFO) processes, and porous carbon (PCC, 30 g/L), along with FeSO4.7H2O, 200 mg/L and H2O2 (30% v/v), 0.4 ml/L were used as a catalyst in a weakly acidic medium. For the biocatalytic processes, the microbial culture cultivated from sewage and incorporated into a Fluidized Immobilized Carbon Catalytic Oxidation reactor (FICCO), and dominant species are Pseudomonas Putida sp., Pseudomonas Kilionesis sp., and Pseudomonas Japonica sp., which is identified by using 16 S rDNA sequencing analysis. The COD and BOD5 removal efficiency of 65–93% and 70–82%, and follow the pseudo-second-order kinetic model with the rate constants of 1.0 × 10−4 L COD−1 h−1, 1.5 × 10−3 L COD−1 h−1 and 3.0 × 10−3 L COD−1 h−1 in the HFO–FICCO-CAACO catalytic processes. The optimized hydraulic retention time (HRT) of FICCO reactor was 24 h, and 1 h for the Chemo-Autotrophic Activated Carbon Oxidation (CAACO) reactor for maximum organics removal. MAP (Magnesium Ammonium Phosphate precipitation) process showed 90% of NH4+-N elimination and recovered it as a struvite fertilizer at an optimum molar ratio of 1:1.3:1.3 (NH4+-N: Na2HPO4.2H2O: MgO). FT-IR, UV–visible, and UV-fluorescence data confirm the effective elimination of organics. Hence, this integrated treatment system is appropriate for the management of pharmaceutical wastewater especially elimination of complex organic molecules and the recovery of nitrogen in the wastewater.

Effect of Activator/Precursor Mass Ratio on Sulfur-Doped Porous Carbon for Catalytic Oxidation of Aqueous Organics with Persulfate

Effect of Activator/Precursor Mass Ratio on Sulfur-Doped Porous Carbon for Catalytic Oxidation of Aqueous Organics with Persulfate

Sodium hypochlorite and Cu–O–Mn/ columnar activated carbon catalytic oxidation for treatment of ultra-high concentration polyvinyl alcohol wastewater

Complete degradation of high concentration polyvinyl alcohol (PVA) is challenging. In this article, a two-stage process of NaClO pre-oxidation and columnar activated carbon (loaded with metal active components) catalytic oxidation was used to treat high concentration PVA wastewater. The degree of polymerization of PVA is 2400 and the water concentration is 15 wt %. In the first stage, NaClO efficiently broken long chain to short, the viscosity of PVA solution decreased from 45,100 mPaS to 4.65 mPaS. And in the second stage, the short chain was further oxidized to small molecules under H2O2 with catalysts. The solution COD decreased from 206,240 mg/L to 38.38 mg/L. The composition of catalysts and the reaction conditions were optimized, the degradation mechanism was discussed. According to the experimental results, small pore size (8–10 mesh) activated carbon loaded copper and manganese catalyst (C1M1AC-S) was the best choice. The optimal conditions of C1M1AC-S were: molar ratio of copper to manganese was 2:1, the loading rate was 25 wt% and the dosage was 9.76 mg/100 ml. The whole process is mild (25 °C–40 °C) and reaction time is short (100 min). Moreover, free radical scavenging experiments shown that the catalytic oxidation stage follows the mechanism of hydroxyl radical reaction.

Synthesis of YFeO<sub>3-δ</sub> and LaFeO<sub>3-δ</sub> Perovskites with High Catalytic Activity in Carbon Oxidation Reactions

YFeO3-δ (δ = 0.26) and LaFeO3-δ (δ = 0.5) perovskites with a high specific surface and oxygen non-stoichiometry was firstly synthesized by pyrolysis of polymer-salt compositions. It was shown that the catalytic oxidation of carbon in the presence of these complex oxide systems proceeds in the range of 400 - 700 °С, with a maximum temperature at 556 °С for YFeO3-δ; and 380 - 620 °С ,with a maximum temperature at 501 °С for LaFeO3-δ, in one-stage mode for both. By means of thermal analysis and diffractometry, it was shown that there is no contribution to the soot oxidation mechanism by cyclic perovskite surface transformations, due to the reduction of metal oxides by the soot and their subsequent reoxidation. It has been established that the basis of the catalytic reaction mechanism for both perovskites is the presence of oxygen vacancies on the surface of complex oxides.

Integrated catalytic oxidation and biological treatment of spent caustic wastewater discharged from petrochemical industries

The integrated catalytic oxidation and biological treatment of the spent caustic wastewater (SCWW) discharged from the petrochemical industry were carried out in the present investigation. The SCWW was characterized by COD 19,246–21,054 mg/L, sulphide 4280–5092 mg/L, and phenol compounds 2349–2716 mg/L. The BOD/COD of the wastewater was around 0.196–0.216 mg/L, indicating a poor biodegradable nature. The integrated treatment scheme attempted in the present investigation comprised techniques such as catalytic functionalization oxidation reactor (CFOR), heterogeneous activated carbon Fenton catalytic oxidation (HAFCO), Fenton activated carbon catalytic oxidation (FACCO) and fluidized immobilized cell carbon oxidation (FICCO). The integrated catalytic reactors demonstrated 100% efficiency in removing sulphide, without emitting them into the atmosphere, 96.7% in removing phenol, 95.3% in removing COD and 99.2% in removing BOD. The removal of dissolved organics from SCWW by integrated oxidation process was confirmed through instrumental analysis such as UV–visible and Fourier transform infrared spectroscopy.

Integrated thermophilic enzyme-immobilized reactor and high-rate biological reactors for treatment of palm oil-containing wastewater without sludge production.

Bacillus pumilus, the thermophilic microorganism, was used to biosynthesise lipase of specific activity 5173 U. The purified lipase was highly stable in the pH range from 1 to 7 and temperature at 50°C. The functionalized nanoporous activated carbon matrix was used for the immobilization of lipase at the optimum conditions and was used for the hydrolysis of palm oil-containing wastewater at optimum time, 3h, pH 7, and at temperature 50°C. The hydrolyzed palm oil wastewater was treated in an upflow anaerobic reactor for the removal of soluble COD at hydraulic retention time (HRT) of 3 days. The anaerobic-treated wastewater was applied to the fluidized immobilized carbon catalytic oxidation (FICCO) reactor at HRT of 16h to reduce the soluble COD. The FICCO-treated wastewater was further treated in chemo-autotrophic activated carbon oxidation (CAACO) reactor to reduce the COD less than 100mg/L.

Nanofabricated Catalyst Particles for the Investigation of Catalytic Carbon Oxidation by Oxygen Spillover.

The catalytic oxidation of carbon by molecular oxygen was studied using C/Pt, Pt/C, Pt/Al2O3/C, Pt/CeO2/C, Al2O3/C, and CeO2/C model samples prepared by hole-mask colloidal lithography. By this technique, the degree of contact between platinum and carbon was controlled with high precision. The oxidation of carbon was monitored using atomic force microscopy and scanning electron microscopy. The results show that Pt in direct contact with carbon catalyzes the oxidation of carbon by spillover of dissociated oxygen from Pt to carbon. By physically separating Pt and carbon with a 10 nm thin spacer layer of Al2O3, the oxygen spillover was entirely blocked. However, through a corresponding spacer layer of CeO2, carbon oxidation was still observed, either by oxygen spillover from Pt to carbon or directly dissociated on the ceria, although at a slower rate compared to the case with no spacer layer between Pt and carbon.

Formation and Oxidation/Gasification of Carbonaceous Deposits: A Review

A wide variety of hydrocarbon processes, catalytic or noncatalytic, involve the formation of carbon deposits, either on catalysts or on reactor (or engine/exhaust) surfaces. Therefore, researchers have developed a large array of catalysts to aid the combustion of these deposits. Recently, the mechanism of catalytic carbon oxidation and/or gasification has been the focus of research in an attempt to design better catalysts for carbon removal. With this approach, understanding the mechanism of formation of different types of carbon deposits is desired. Efforts undertaken for studying oxidation or gasification of various forms of carbon deposits are discussed in this review, along with the techniques used to study the mechanism of oxidation/gasification. The kinetics of catalyzed and noncatalytic carbon oxidation are described in detail. The effect of reactive gases such as NOx, water vapor, CO2, and SO2 on the gasification behavior of carbon deposits is also discussed. Reaction rates of oxidation/gasificati...

Synthesis of TiO2 nanoparticles containing Fe, Si, and V using multiple diffusion flames and catalytic oxidation capability of carbon-coated nanoparticles

Titanium dioxide (TiO2) nanoparticles containing iron, silicon, and vanadium are synthesized using multiple diffusion flames. The growth of carbon-coated (C–TiO2), carbon-coated with iron oxide (Fe/C–TiO2), silica-coated (Si–TiO2), and vanadium-doped (V–TiO2) TiO2 nanoparticles is demonstrated using a single-step process. Hydrogen, oxygen, and argon are utilized to establish the flame, with titanium tetraisopropoxide (TTIP) as the precursor for TiO2. For the growth of Fe/C–TiO2 nanoparticles, TTIP is mixed with xylene and ferrocene. While for the growth of Si–TiO2 and V–TiO2, TTIP is mixed with hexamethyldisiloxane (HMDSO) and vanadium (V) oxytriisopropoxide, respectively. The synthesized nanoparticles are characterized using high-resolution transmission electron microscopy (HRTEM) with energy-filtered TEM for elemental mapping (of Si, C, O, and Ti), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption BET surface area analysis, and thermogravimetric analysis. Anatase is the dominant phase for the C–TiO2, Fe/C–TiO2, and Si–TiO2 nanoparticles, whereas rutile is the dominant phase for the V–TiO2 nanoparticles. For C–TiO2 and Fe/C–TiO2, the nanoparticles are coated with about 3-5-nm thickness of carbon. The iron-based TiO2 nanoparticles significantly improve the catalytic oxidation of carbon, where complete oxidation of carbon occurs at a temperature of 470 °C (with iron) compared to 610 °C (without iron). Enhanced catalytic oxidation properties are also observed for model soot particles, Printex-U, when mixed with Fe/C-TiO2. With regards to Si–TiO2 nanoparticles, a uniform coating of 3 to 8 nm of silicon dioxide is observed around the TiO2 particles. This coating mainly occurs due to variance in the chemical reaction rates of the precursors. Finally, with regards to V–TiO2, vanadium is doped within the TiO2 nanoparticles as visualized by HRTEM and XPS further confirms the formation of V4+ and V5+ oxidation states.

Optimization of a direct carbon fuel cell for operation below 700 °C

Direct carbon fuel cells (DCFCs) are the most efficient technology to convert solid carbon energy to electricity and thus could have a major impact on reducing fuel consumption and CO2 emissions. The development of DCFCs to commercialisation stage is largely prohibited by their poor power densities due to the high resistive loss from anode. Here, we report a high-performance Sm0.2Ce0.8O1.9 electrolyte-supported hybrid DCFC with Ba0.5Sr0.5Co0.8Fe0.2O3−δ cathode and optimised anode configuration. The catalytic oxidation of carbon is improved, which results in an area specific resistance of only 0.41 Ω cm2 at 650 °C at the anode. The hybrid DCFC achieves a peak power density of 113.1 mW cm−2 at 650 °C operating on activated carbon. The stability of the fuel cell has also been improved due to the optimised current collection.

Structural transformations of CuMoO4 in the catalytic oxidation of carbon

The catalytic combustion of carbon black at 350–420°C in the presence of CuMoO4 has been investigated. The separate catalyst reduction and reoxidation stages make nonadditive contributions to the overall heat of the process. This indicates the formation of catalytically intermediate compounds during the redox reactions. The reduction of the catalyst with carbon yields the copper(I) molybdates Cu6Mo5O18 and Cu4Mo5O17 on its surface. The reoxidation of the reduced phases is accompanied by the release of Cu2O and MoO3 followed by the formation of the active phase Cu4 − x Mo3O12, which is capable of activating carbon black combustion.

Preparation and Application of Iron-Loaded Activated Carbon for Catalytic Oxidation of Phenol Wastewater

The catalyst was prepared by using activated carbon as the carrier and loading with iron oxide as the active component, the main factors affecting the preparation of this catalyst were further analyzed. When this catalyst was applied to the electrocatalytic oxidation degradation of phenol simulation wastewater, the affecting factors on the removing rate of phenol were studied. Under the optimized preparation conditions of soaking in 2mol/L HCl and 5%NaOH for 12 h, respectively, and then in FeCl3 with the concentration of 10% for 24h, calcination temperature 240°C for 2.5 h, the optimum catalytic activity could be obtained.

Nanostructured Ceria−Silver Synthesized in a One-Pot Redox Reaction Catalyzes Carbon Oxidation

We introduce a new concept for a nanomaterial in terms of both synthesis and properties. The nanomaterial, aggregates of ceria particles around central silver metal (CeO(2)-Ag), was fabricated by a one-pot selective redox reaction using cerium(III) and silver(I) autocatalyzed by silver metal without the need for surfactants or organic compounds. This unique nanostructure is suitable as a catalyst, in contrast to core-shell materials wherein the shell deactivates the catalyst metal. The material was developed to be intimately related to catalytic carbon oxidation.

Titanium-supported nickel-copper oxide catalysts for oxidation of carbon(II) oxide

Nickel-copper compositions for catalytic oxidation of carbon(II) oxide to carbon(IV) oxide were prepared by impregnation of oxide films on titanium surface, obtained by plasma electrolytic oxidation followed by annealing. Plasma electrolysis oxide coatings with a layer thickness of 5 to 50 μm were generated using different electrolytes. The compositions were studied by X-ray powder diffraction, X-ray spectral analysis, and electron microscopy, and moisture absorption of the initial plasma electrolytic structures was estimated. A linear correlation was found between the overall concentration of nickel and copper (4 to 25 mol %) in the surface layer of ∼2–5-μm compositions and their catalytic activity. The overall concentration of nickel and copper was found to increase in parallel with the moisture absorption of plasma electrolytic oxidation coatings. Nickel-copper compositions based on plasma electrolytic oxidation coatings generated in a silicate electrolyte displayed the best catalytic, mechanical, and adhesion properties.

Experimental study on the effects of H 2O on PCDD/Fs formation by de novo synthesis in carbon/CuCl 2 model system

The effects of H 2O vapor on de novo synthesis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and biphenyls (PCB) were investigated at two levels (none and 10 vol.%) in various model systems containing five different carbons, CuCl 2, and quartz, exposed to a flow of 10% O 2/N 2 at 300 °C. The influence of H 2O was studied on (1) speciation and behavior of copper compounds, (2) catalytic oxidation of carbons of distinct reactivity, and (3) formation of organic chlorine compounds, with the aim to investigate any effects on de novo synthesis. It is found that H 2O converts CuCl 2 to CuCl 2·CuO, and finally to CuO in a flow of 10% O 2/N 2 at 300 °C and that it decreases of organic chlorine (C–Cl) formation. When CuCl 2 is supported on carbon, the addition of H 2O promotes the catalytic oxidation of this carbon. When CuCl 2 is supported on quartz, however, H 2O inhibits carbon oxidation. A decrease in chlorination level of PCDD/Fs and PCBs with water addition is observed for all (six) model ashes; yet this addition affects the yields of PCDD/Fs and PCBs differently. Under the experimental conditions tested H 2O does not react with Cu 2Cl 2, which is the catalyst of carbon oxidation. On the basis of the experimental results, the following mechanism is proposed: conversion of CuCl 2 into CuO which is less reactive in de novo synthesis and promotion of catalytic oxidation of carbon by Cu 2Cl 2.

Catalytic Carbon Oxidation in The Presence of Cerium Oxide: Experimental Study and Modeling of The Effect of Oxygen Concentration

AbstractThe catalytic combustion of carbon black (CB) used as a model of diesel soot in tight contact with a commercial ceria (CeO2) was investigated. Oxygen mole fractions of 10, 5, and 1 % in the gas phase were tested in order to gain a better understanding of the redox properties of ceria and the mechanism of the catalytic oxidation of carbon black. Both isothermal and temperature programmed runs are performed to extract kinetic parameters, such as activation energy and reaction order with respect to oxygen partial pressure. The experimental data are used to propose a model of CB oxidation in the presence of CeO2 allowing the simulation of carbon oxidation.

Catalytic Carbon Oxidation Over Ruthenium‐Based Catalysts

Außergewöhnliche Aktivität weist ein zeolithgebundener Rutheniumkatalysator in der Kohlenstoffoxidation auf (siehe Diagramm; Y=Gewichtsverlust an Kohlenstoff), der, anders als Platinkatalysatoren, ohne NOx im Gasstrom funktioniert. Der Katalysator bietet Möglichkeiten für die katalytische Rußoxidation in Dieselabgasfiltern.

Catalytic Carbon Oxidation Over Ruthenium‐Based Catalysts

Exceptional activity in carbon oxidation is displayed by a zeolite-supported ruthenium catalyst (see diagram; Y=carbon weight loss) that unlike platinum catalysts does not require the presence of NOx in the gas stream. This catalyst opens up a new route for catalytic soot oxidation in diesel engine exhaust filters.