Aerobic Oxidation Process Research Articles

Effect of climate change in WWTPs with a focus on MBR infrastructure

Climate change is expected to be one of the main challenges for urban wastewater systems in the next decades, and it is estimated that it will have a dual effect on wastewater treatment plants (WWTPs). The processes occurring in a WWTP are affected by climate change; more extreme weather events and earlier snowmelt runoff will lead to more untreated sewer overflows, increased flooding, etc. On the other hand, wastewater treatment contribute to climate change itself, as during wastewater treatment greenhouse gases, including carbon dioxide (CO2) from aerobic (oxidation processes), methane (CH4) from anaerobic processes and nitrous oxide (N2O) associated with nitrification/denitrification processes, can be emitted to the atmosphere. MBR is currently considered a rather mature technology (not innovative) with several full-scale applications; N2O is also produced during the nitritation process (i.e. ammonium oxidation to nitrite). Moreover, the microbial communities developed in MBRs are exposed to completely different conditions depending on the season of the year (spring, summer and autumn). The various problems associated with climate change and MBRs/WWTP operation and the solutions that can be applied to deal with them are summarized in this paper.

Transformation of ethers into aldehydes or ketones: a catalytic aerobic deprotection/oxidation pathway

A facile and efficient protocol for direct transformation of p-methoxybenzyl (PMB) ethers to aldehydes or ketones via a catalytic aerobic oxidation process has been developed. The reaction was performed with the combination of catalytic amounts of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,2,6,6-tetramethylpiperidine N-oxy (TEMPO), and tert-butyl nitrite (TBN), with molecular oxygen as terminal oxidant. A variety of PMB ether substrates derived from benzylic alcohols, heteroaromatic alcohols, and aliphatic alcohols, were converted to their corresponding carbonyl compounds in good conversions and selectivities.

혐기소화액의 고온호기산화 공정 적용에 관한 연구

We studied the possibility on the application of the Thermophilic Aerobic Oxidation (TAO) process to anaerobic digestate stabilization. In treating digestate with TAO reactor the internal temperature of the reactor was increasing higher and <TEX>$51^{\circ}C$</TEX> and over was maintained after 6 days on. The physiochemical compositions of liquids increased from pH 8.1 to 9.8 and EC decreased from 29.8 to 12.0 mS/cm in treating process of digestate with TAO reactor. CODcr decreased from 22,654 to 18,843 mg/L, showed about 16.82% of remove efficiency. TN and <TEX>$NH_4-N$</TEX> decreased from 4,813 to 1,733 mg/L, from 3,815 to 812 mg/L respectively, which showed about 64.0% and 78.7% of removal efficiency respectively.

Synthesis of Pyrazolo[1,5‐a]quinolines from 1‐Aryl‐5‐styrylpyrazoles via Intramolecular Friedel‐Crafts Reaction/Aerobic Oxidation

Various pyrazolo[1,5‐a]quinolines were synthesized via the intramolecular Friedel‐Crafts reaction of 1‐aryl‐5‐styrylpyrazoles and the following base‐catalyzed aerobic oxidation process. The required 1‐aryl‐5‐styrylpyrazoles were readily prepared from the corresponding conjugated dienones and arylhydrazines in a one‐pot process.

Removal of ethylbenzene and p-nitrophenol using combined approach of advanced oxidation with biological oxidation based on the use of novel modified prepared activated sludge

The treatment of a synthetically prepared wastewater containing ethylbenzene and p-nitrophenol has been investigated using combined treatment schemes based on the advanced oxidation process followed by the conventional aerobic oxidation process (using primary activated sludge (PAS), modified prepared activated sludge (MPAS) based on the use of combined sludge from different treatment sources and activated sludge (AS)). The operating conditions for the pretreatment scheme have been optimized and it has been observed that initial pH of 3–3.5, a Fe2+ dosage of 2.0gL−1 and a H2O2 dosage of 1.5gL−1 in combination with ultrasound gives the best performance. Approximately, 55–70% reduction in the chemical oxygen demand (COD) was obtained at optimum conditions after pretreatment from initial conditions of COD as 3642 and 3417mgL−1 and BOD as 881 and 533mgL−1 for the wastewater containing ethylbenzene and p-nitrophenol respectively. From an initial BOD5/COD (BI) value of around 0.15–0.2, the ratio was found to increase to about 0.30–0.35 after pretreatment, which is considered good for the aerobic treatment. In the case of aerobic oxidation, promising results were obtained for the modified prepared activated sludge giving better conversion ability of intermediates into solid residue and higher biomass yield that could be separated by simple filtration as compared to the primary activated or the activated sludge treatment. The best treatment approach as established in the work was ultrasound assisted Fenton process as the pretreatment followed by biological oxidation using MPAS.

ChemInform Abstract: Copper‐Catalyzed Aerobic Oxidative C—C Bond Cleavage of 1,3‐Diaryl‐diketones to Synthesize 1,2‐Diketones.

AbstractAliphatic 1,3‐diketones do not react to the corresponding 1,2‐diketones.

Evaluation of performance in a combined UASB and aerobic contact oxidation process treating acrylic wastewater

The lab-scale and full-scale performance of a combined mesophilic up-flow anaerobic sludge blanket (UASB) and aerobic contact oxidation (ACO) process for treating acrylic wastewater was studied. During lab-scale experiment, the overwhelmed volumetric load for UASB was above 6 kg chemical oxygen demand (COD) ·(m−3·d−1) since COD removal efficiency dropped dramatically from 73% at 6 kg COD·(m−3·d−1) to 61% at 7 kg COD·(m−3·d−1) and 53% at 8 kg COD·(m−3·d−1). Further results showed that an up-flow fluid velocity of 0.5 m h−1 for UASB obtained a highest COD removal efficiency of 75%, and the optimum COD volumetric load for the corresponding ACO was 1.00 kg COD·(m−3·d−1). Based on the configuration of the lab-scale experiment, a full-scale application with an acrylic wastewater treatment capacity of 8 m3 h−1 was constructed and operated at a volumetric load of 5.5 kg COD·(m−3·d−1), an up-flow fluid velocity of 0.5 m h−1 for UASB and a volumetric load of 0.9 kg COD·(m−3·d−1) for ACO; and the final effluent COD was around 740 mg L−1. The results suggest that a combined UASB–ACO process is promising for treating acrylic wastewater.

Development of 2-Chlorophenol Sensor Based on a Fiber Optic Oxygen Transducer via Oxidation Reaction Catalyzed by Tetranitro Iron (II) Phthalocyanine

This paper develops a 2-chlorophenol sensor based on the improvement of a fiber optic oxygen transducer. The measurement of a sensor depends on the principle of stoichiometric relationship between dissolved oxygen and 2-chlorophenol in catalytic oxidation reaction. Specifically, oxygen was consumed fast in oxidation of 2-chlorophenol catalyzed by tetranitro iron (II) phthalocyanine (TNFe(II)Pc), and the concentration changes of dissolved oxygen could be measured by a fiber optic oxygen transducer. The phase-modulation technology was employed to record the signals of phase delay responding to the aerobic oxidation process catalyzed by TNFe(II)Pc. In addition, the sensing performance of this sensor could be demonstrated by a modified Stern-Volmer equation, φ = 0.12 + 3710[2 - CP] (R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.9949), where φ and [2-CP] represent the phase delay and concentration of 2-chlorophenol, respectively. The detection limit of this sensor is 8.0 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> M. In addition, this sensor shows the satisfactory results compared with that of HPLC method for detection of the samples from Changjiang river.

Системные механизмы утомления при физических нагрузках циклической направленности

Mechanisms of fatigue during exercise of circular orientation of various volume and intensity are analyzed from the position of functional systems theory. Peculiarities of fatigue anaerobic metabolism in high-speed sports, aerobic-anaerobic metabolism in sports disciplines connected with high speed endurance and aerobic metabolism in running the long and very long distances are considered. Sprint is dominated by anaerobic processes in working skeletal muscles and central mechanisms of fatigue. Central fatigue is ahead of peripheral fatigue of neuromuscular system. Anaerobic and aerobic oxidation processes occur when running athlete on medium distances. The effects of hypoxia, hypocapnia and accumulation of oxidation products from the working muscles begin to emerge. Disorders in respiratory and cardiovascular system appear. At long distances deep metabolic aerobic changes come, toxic products of metabolism accumulate, water-salt balance impairs, the cellular and molecular processes of excitation in the central and peripheral nervous system change. A combination of different disabilities leads to decrease the athlete neuromuscular system efficiency. System approach enables to reveal the fine line between achieving the body of a new quality level of adaptation to physical loads and breakdowns of compensatory mechanisms associated with the stress of functional systems for ensuring the work.

Metabolic Effects of a Succinic Acid&lt;Based Substrate Antihypoxant

The paper discusses promises for clinical use of substrate antihypoxants. Objective: to investigate the efficacy of succinate containing substrate antihypoxants on systemic oxygen consumption, blood buffer capacity, and changes in the mixed venous blood level of lactate when they are used in gravely sick patients and victims with marked metabolic posthypoxic disorders. Subjects and methods. The trial enrolled 30 patients and victims who had sustained an episode of severe hypoxia of mixed genesis, the severity of which was evaluated by the APACHE II scale and amounted to 23 to 30 scores with a 46 to 70.3% risk of death. The standard infusion program in this group involved the succinate-containing drug 1.5% reamberin solution in a total dose of 800 ml. A comparison group included 15 patients who had undergone emergency extensive surgery for abdominal diseases. 400 ml of 10% glucose solution was used as an infusion medium. Oxygen consumption (VO 2 ml/min) and carbon dioxide production (VCO 2 ml/min) were measured before infusion and monitored for 2 hours. Arterial blood gases and acid-base balance (ABB) parameters and mixed venous blood lactate levels were examined. Measurements were made before and 30 minutes after the infusion of reamberin or glucose solution. Results. Infusion of 1.5% reamberin solution was followed by a significant increase in minute oxygen consumption from 281.5±21.2 to 310.4±24.4 ml/min. CO 2 production declined (on average, from 223.3±6.5 to 206.5±7.59 ml/min). During infusion of 10% glucose solution, all the patients of the comparison group showed a rise in oxygen consumption from 303.6±33.86 to 443.13±32.1 ml/min, i.e. about 1.5-fold. VCO 2 changed similarly. The intravenous infusion of 800 ml of 1.5% reamberin solution raised arterial blood buffer capacity, which was reflected by changes in pH, BE, and HCO 3 . There was a clear trend for lactate values to drop in the mixed venous blood. The intravenous injection of 400 ml of 10% glucose solution caused no significant changes in major ABB indicators, which reinforced the statement that there is a difference in the metabolism of these substrates. Conclusion. The succinate-containing drugs are able to compensate for metabolic acidosis. Their use is followed by increased oxygen consumption and activated aerobic oxidation processes. The basis of their antihypoxant properties was thought to be recovered intracellular aerobic metabolic processes due to corrected intracellular metabolic acidosis and increased blood buffer capacity.

Copper-Catalyzed Aerobic Oxidative C–C Bond Cleavage of 1,3-Diaryl­diketones To Synthesize 1,2-Diketones

An aerobic oxidative C–C bond cleavage of 1,3-diaryldiketones for the synthesis of 1,2-diketones by using O₂ as the oxidant has been developed. Control experiments illustrate that the copper catalyst not only assist the aerobic oxidative process of 1,3-diketones, but also catalyze the 1,2-Wagner–Meerwein-type rearrangement process.

Frontiers in the microbial processes of ammonia oxidation in soils and sediments

Two recent discoveries in nitrogen (N) cycling processes, i.e., archaeal ammonia oxidizers and anaerobic ammonia (ammonium) oxidation (anammox), have triggered great interest in studying microbial ammonia oxidation processes. The purpose of this review is to highlight recent progress in ammonia oxidation processes in soils and sediments and to propose future research activities in this topic. Aerobic ammonia oxidation and anammox processes are linked through the production and consumption of nitrite, respectively, thereby removing the reactive N (NH4 +, NO2 −, NO3 −) from soil and sediment ecosystems. Ammonia-oxidizing microorganisms are widely distributed in soils and sediments, and increasing evidence suggests that ammonia-oxidizing archaea and bacteria are functionally dominant in the ammonia oxidation of acid soils and other soils, respectively. The widespread occurrence and great variation in the abundance of anammox bacteria indicate their heterogeneous distribution and niche differentiation. Therefore, the worldwide distribution of both microbial groups in nature has stimulated researchers to investigate the physiology and metabolism of related groups, as well as appraising their contribution to N cycling. We summarized the current progress and provided future perspectives in the microbiology of aerobic and anaerobic ammonia oxidation in soils and sediments. With increasing concern and interest in soil and sediment ammonia oxidation processes, studies in the microbial mechanisms underlying nitrification and anammox, as well as their interactions, are essential for understanding their contribution to the loss of N either through nitrate leaching or N-related gas emissions.

ChemInform Abstract: Nitroxide‐Catalyzed Transition‐Metal‐Free Aerobic Oxidation Processes

AbstractReview: 195 refs.

Trace metal pyritization variability in response to mangrove soil aerobic and anaerobic oxidation processes

The degree of iron pyritization (DOP) and degree of trace metal pyritization (DTMP) were evaluated in mangrove soil profiles from an estuarine area located in Rio de Janeiro (SE Brazil). The soil pH was negatively correlated with redox potential (Eh) and positively correlated with DOP and DTMP of some elements (Mn, Cu and Pb), suggesting that pyrite oxidation generated acidity and can affect the importance of pyrite as a trace metal-binding phase, mainly in response to spatial variability in tidal flooding. Besides these aerobic oxidation effects, results from a sequential extraction analyses of reactive phases evidenced that Mn oxidized phase consumption in reaction with pyrite can be also important to determine the pyritization of trace elements. Cumulative effects of these aerobic and anaerobic oxidation processes were evidenced as factors affecting the capacity of mangrove soils to act as a sink for trace metals through pyritization processes.

Aerobic and Anaerobic Ammonia-Oxidizing Microorganisms in Low-Temperature Hydrothermal Fe-Si-rich Precipitates of the Southwestern Pacific Ocean

Fe-Si-rich hydrothermal precipitates are distributed widely in low-temperature diffusing hydrothermal fields. Due to the significant contribution of Fe-oxidizing bacteria (FeOB) to the formation of this type of hydrothermal precipitates, previous studies focus mostly on investigating FeOB-related microbial populations, albeit these precipitates actually accommodate abundant other microbial communities, particularly those involved in marine nitrogen cycle. In this study, we investigated the composition, diversity, and abundance of aerobic and anaerobic ammonia-oxidizing microorganisms dwelling in low-temperature Fe-Si-rich hydrothermal precipitates of the Lau Integrated Study Site based on ammonia monooxygenase (amoA) gene and 16S rRNA gene. Phylogenetic analysis revealed the common presence of ammonia-oxidizing archaea (AOA), Nitrosospira-like ammonia-oxidizing bacteria (AOB) and anaerobic ammonium-oxidizing anammox (bacteria) in the Fe-Si-rich hydrothermal precipitates. Quantitative PCR analysis showed that AOA dominated the whole microbial community and the abundance of archaeal amoA gene was 2–3 orders of magnitude higher than that of AOB and anammox bacteria. Result of glycerol dialkyl glycerol tetraether analysis confirmed the presence and abundance of AOA. Our results suggest that microbial ammonia oxidations, especially archaeal aerobic ammonia oxidation, are prevalent and pivotal processes in low-temperature diffusing hydrothermal fields. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the supplemental file.

ChemInform Abstract: Highly Selective Wacker Reaction of Styrene Derivatives: A Green and Efficient Aerobic Oxidative Process Promoted by Benzoquinone/NaNO2/HClO4 under Mild Conditions.

AbstractVicinal disubstituted olefins are not suited as starting material.

ChemInform Abstract: An Efficient Synthesis of o‐Terphenyls from Morita—Baylis—Hillman Adducts of Cinnamaldehydes: A Consecutive Bromination, Wittig Reaction 6π‐Electrocyclization, and an Aerobic Oxidation Process.

An efficient synthetic method of o-terphenyls was developed from Morita–Baylis–Hillman adducts. The synthesis was carried out via a sequential bromination of MBH adducts, Wittig reaction with various aldehydes, 6π-electrocyclization, and a base-mediated aerobic oxidation process.

ChemInform Abstract: A Cooperative Catalytic System of Platinum/Iridium Alloyed Nanoclusters and a Dimeric Catechol Derivative: An Efficient Synthesis of Quinazolines Through a Sequential Aerobic Oxidative Process.

AbstractA new polymer‐supported catalyst system consisting of platinum/iridium alloyed nanoclusters and spiro‐bisindane ligand THSI is used for the facile preparation of fused quinazoline derivatives under mild aerobic oxidative conditions.

An efficient synthesis of o-terphenyls from Morita–Baylis–Hillman adducts of cinnamaldehydes: a consecutive bromination, Wittig reaction, 6π-electrocyclization, and an aerobic oxidation process

An efficient synthetic method of o-terphenyls was developed from Morita–Baylis–Hillman adducts. The synthesis was carried out via a sequential bromination of MBH adducts, Wittig reaction with various aldehydes, 6π-electrocyclization, and a base-mediated aerobic oxidation process.

Nitroxide-catalyzed transition-metal-free aerobic oxidation processes

Advances in the field of transition-metal-free nitroxide-catalyzed aerobic oxidation processes are covered in this critical review. Along with the relevant physical properties of nitroxides, their application as oxidation catalysts by using dioxygen as a reagent or terminal oxidant will be discussed. The second part of the review focuses on the use of TEMPO-based nitroxides as catalysts for aerobic alcohol oxidation. Mechanistic studies will also be addressed (130 references).