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Modeling the aqueous reaction kinetics of estriol with ferrate

Cong LI, Naiyun GAO

《化学科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 39-45 doi: 10.1007/s11705-009-0098-4

摘要： In this study the aqueous oxidation kinetics of estriol (E3) by potassium ferrate (K FeO ), a chemical for its strong oxidizing power and for producing a coagulant from its reduced state (i.e. Fe(III)), was evaluated in the range of pH 8-12 with different molar ratios of the reactants. As the degree of Fe(VI) protonation varies with the solution pH, it was found that a first order model was not suitable to describe the oxidation reaction. This paper describes a theoretical representation that closely models the reaction kinetics of E3 and ferrate. From this modeling, the reaction rates of HFe and Fe with E3 have been determined. The results show that the reactivity of HFe with dissociated and undissociated E3 is greater than that of Fe , and that E3 is more reactive in its dissociated state.

关键词： ferrate     estriol     endocrine disruptor     kinetics     oxidation    

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Kinetics of oxidation of dimethyl trisulfide by potassium permanganate in drinking water

Xiaoyan MA, Shifei HU, Hongyu WANG, Jun LI, Jing HUANG, Yun ZHANG, Weigang LU, Qingsong LI

《环境科学与工程前沿（英文）》 2012年 第6卷 第2期   页码 171-176 doi: 10.1007/s11783-011-0319-1

摘要： Metabolites of algae such as geosmin, 2-methylisoborneol etc. are reported to induce pungent odors into drinking water and attract additional scientific attention. Recently, in China, taste and odor outbreaks in drinking water supply have become increasingly common. In source water affected by eutrophication, dimethyl trisulfide, speculated to be produced by decayed algae, was found to be the source of taste and odor issues and can be removed effectively by usual oxidation agents. In this experimental study, batch scale tests were carried out focusing on the removal of dimethyl trisulfide. Reaction kinetics of dimethyl trisulfide oxidized by potassium permanganate in water had been studied; influence factors such as pH, organic substrate, other existed taste, and odor contaminant in equivalent concentration were also discussed. Results showed that dimethyl trisulfide can be removed by potassium permanganate efficiently; the ratio can reach more than 70% with oxidant dosage of 4 mg·L and contact time prolonged to 120 min. The dimethyl trisulfide decomposition followed a second-order kinetics pattern with a rate constant = 0.00213 L·(min·mg) . Typically, the degradation rate of dimethyl trisulfide was increased with the increasing KMnO dosage, but dramatically dropped with the increasing levels of humic acid (1.8–4.5 mg·L ) and other odor-causing compounds (e.g. -cyclocitral, 0–1886.0 μg·L ). Solution pH (5.2–9.0) and initial dimethyl trisulfide concentration did not significantly affected the degradation. This study demonstrates that KMnO oxidation is an effective option to remove dimethyl trisulfide from water.

关键词： odor and taste     oxidation reaction     reaction kinetics     water treatment    

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Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partialoxidation of methane

《化学科学与工程前沿（英文）》 2022年 第16卷 第12期   页码 1726-1734 doi: 10.1007/s11705-022-2188-5

摘要： Chemical looping reforming of methane is a novel and effective approach to convert methane to syngas, in which oxygen transfer is achieved by a redox material. Although lots of efforts have been made to develop high-performance redox materials, a few studies have focused on the redox kinetics. In this work, the kinetics of SrFeO3−δ–CaO∙MnO nanocomposite reduction by methane was investigated both on a thermo-gravimetric analyzer and in a packed-bed microreactor. During the methane reduction, combustion occurs before the partial oxidation and there exists a transition between them. The weight loss due to combustion increases, but the transition region becomes less inconspicuous as the reduction temperature increased. The weight loss associated with the partial oxidation is much larger than that with combustion. The rate of weight loss related to the partial oxidation is well fitted by the Avrami–Erofeyev equation with n = 3 (A3 model) with an activation energy of 59.8 kJ∙mol‒1. The rate law for the partial oxidation includes a solid conversion term whose expression is given by the A3 model and a methane pressure-dependent term represented by a power law. The partial oxidation is half order with respect to methane pressure. The proposed rate law could well predict the reduction kinetics; thus, it may be used to design and/or analyze a chemical looping reforming reactor.

关键词： chemical looping reforming     SrFeO3−δ/CaO·MnO nanocomposite     reduction kinetics     Avrami–Erofeyev model     pressure-dependent term    

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Ozonation of the 5-fluorouracil anticancer drug and its prodrug capecitabine: Reaction kinetics, oxidation

Siyu Chen, Lee Blaney, Ping Chen, Shanshan Deng, Mamatha Hopanna, Yixiang Bao, Gang Yu

《环境科学与工程前沿（英文）》 2019年 第13卷 第4期 doi: 10.1007/s11783-019-1143-2

摘要：

Specific second-order rate constants were determined for 5-FU and CAP with ozone.

Reaction sites were confirmed by kinetics, Fukui analysis, and products.

The olefin moiety was the main ozone reaction site for 5-FU and CAP.

Carboxylic acids comprised most of the residual TOC for 5-FU.

Ozonation removed the toxicity associated with 5-FU and products but not CAP.

关键词： Ozone     5-fluorouracil     Capecitabine     Hydroxyl radicals     Chemotherapy agents     Toxicity    

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Product identification and toxicity change during oxidation of methotrexate by ferrate and permanganate

《环境科学与工程前沿（英文）》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1501-8

摘要：

• Oxidation of methotrexate by high-valent metal-oxo species was first explored.

关键词： Anticancer drugs     High-valent metal-oxo species     Oxidation kinetics     Reaction mechanisms     Multi-endpoint toxicity    

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Characterization of value-added chemicals derived from the thermal hydrolysis and wet oxidation of sewage

Milan Malhotra, Anurag Garg

《环境科学与工程前沿（英文）》 2021年 第15卷 第1期 doi: 10.1007/s11783-020-1305-2

摘要： Abstract • Hydrothermal treatment can greatly improve resource recovery from sewage sludge. • tCOD removal during WO was ~55% compared with ~23% after TH. • TOC solubilization during hydrothermal treatment followed first-order kinetics. • Solids and carbon balance confirmed loss of organics during thermal hydrolysis. • Reaction pathways for thermal hydrolysis and wet oxidation are proposed. We evaluated the effect of hydrothermal pretreatments, i.e., thermal hydrolysis (TH) and wet oxidation (WO) on sewage sludge to promote resource recovery. The hydrothermal processes were performed under mild temperature conditions (140°C–180°C) in a high pressure reactor. The reaction in acidic environment (pH= 3.3) suppressed the formation of the color imparting undesirable Maillard’s compounds. The oxidative conditions resulted in higher volatile suspended solids (VSS) reduction (~90%) and chemical oxygen demand (COD) removal (~55%) whereas TH caused VSS and COD removals of ~65% and ~27%, respectively at a temperature of 180°C. During TH, the concentrations of carbohydrates and proteins in treated sludge were 400–1000 mg/L and 1500–2500 mg/L, respectively. Whereas, WO resulted in solids solubilization followed by oxidative degradation of organics into smaller molecular weight carboxylic acids such as acetic acid (~400–500 mg/L). Based on sludge transformation products generated during the hydrothermal pretreatments, simplified reaction pathways are predicted. Finally, the application of macromolecules (such as proteins), VFAs and nutrients present in the treated sludge are also discussed. The future study should focus on the development of economic recovery methods for various value-added compounds.

关键词： Hydrothermal pretreatment     Reaction kinetics     Reaction pathway     Sewage sludge     Thermal hydrolysis     Wet oxidation    

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Kinetics of microwave-enhanced oxidation of phenol by hydrogen peroxide

Deming ZHAO, Jie CHENG, Michael R. HOFFMANN

《环境科学与工程前沿（英文）》 2011年 第5卷 第1期   页码 57-64 doi: 10.1007/s11783-010-0251-9

摘要： Aqueous solutions of phenol were oxidized by hydrogen peroxide assisted by microwave (MW) irradiation. A simple kinetic model for the overall degradation of phenol in the presence of excess H O is proposed in which the degradation rate of phenol is expressed as a linear function of the concentrations of phenol and H O . A detailed parametric study showed that the degradation rate of phenol increased with increasing [H O ] until saturation was observed. Phenol degradation followed apparent zero-order kinetics under MW radiation or H O oxidation. However, after 90 min of irradiation, the observed kinetics shifted to pseudo first order. The overall reaction rates were significantly enhanced in the combined MW/H O system, mainly because microwave could accelerate H O to generate hydroxyl radical ( OH) and other reactive oxygen intermediates. The observed synergetic effects of the MW/H O process resulted in an increased in the net reaction rate by a factor of 5.75. When hydrogen peroxide is present in a large stoichiometric excess, the time required to achieve complete mineralization is reduced significantly.

关键词： microwave (MW) irradiation     hydrogen peroxide     phenol     synergetic effects     kinetic model    

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Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿（英文）》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1255-8

摘要： • Mechanisms of redox reactions of Fe- and Mn-oxides were discussed. • Oxidative reactions of Mn- and Fe-oxides in complex systems were reviewed. • Reductive reaction of Fe(II)/iron oxides in complex systems was examined. • Future research on examining the redox reactivity in complex systems was suggested. Conspectus Redox reactions of Fe- and Mn-oxides play important roles in the fate and transformation of many contaminants in natural environments. Due to experimental and analytical challenges associated with complex environments, there has been a limited understanding of the reaction kinetics and mechanisms in actual environmental systems, and most of the studies so far have only focused on simple model systems. To bridge the gap between simple model systems and complex environmental systems, it is necessary to increase the complexity of model systems and examine both the involved interaction mechanisms and how the interactions affected contaminant transformation. In this Account, we primarily focused on (1) the oxidative reactivity of Mn- and Fe-oxides and (2) the reductive reactivity of Fe(II)/iron oxides in complex model systems toward contaminant degradation. The effects of common metal ions such as Mn2+ , Ca2+, Ni2+, Cr3+ and Cu2+, ligands such as small anionic ligands and natural organic matter (NOM), and second metal oxides such as Al, Si and Ti oxides on the redox reactivity of the systems are briefly summarized.

关键词： Iron oxides     manganese oxides     reduction     oxidation     complex systems     reaction kinetics and mechanisms    

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Accelerated degradation of orange G over a widepH range in the presence of FeVO

Xiaoxia Ou, Jianfang Yan, Fengjie Zhang, Chunhua Zhang

《环境科学与工程前沿（英文）》 2018年 第12卷 第1期 doi: 10.1007/s11783-018-1013-3

摘要： In this study, FeVO was prepared andused as Fenton-like catalyst to degrade orange G (OG) dye. The removalof OG in an aqueous solution containing 0.5 g·L FeVO and 15 mmol·L hydrogen peroxide at pH 7.0 reached 93.2%. Similar rates were achievedat pH 5.7 ( = 0.0471 min ), pH 7.0 ( = 0.0438 min ), and pH 7.7 ( = 0.0434 min ). The FeVO catalyst successfullyovercomes the problem faced in the heterogeneous Fenton process, i.e.,the narrow working pH range. The data for the removal of OG in FeVO systems containing H O conform to the Langmuir–Hinshelwood model ( = 0.9988),indicating that adsorption and surface reaction are the two basicmechanisms for OG removal in the FeVO –H O system. Furthermore, the irradiationof FeVO by visible light significantly increasesthe degradation rate of OG, which is attributed to the enhanced ratesof the iron cycles and vanadium cycles.

关键词： Azo dye     Degradation     FeVO4     Kinetics     Advanced oxidation processes    

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Theoretical insights into influence of additives on sulfamethoxazole crystal growth kinetics and mechanisms

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1503-1515 doi: 10.1007/s11705-022-2294-4

摘要： In this work, the influence of the initial chemical potential gradient, stirring speed, and polymer type on sulfamethoxazole (SMX) crystal growth kinetics was systematically investigated through density functional theory (DFT) calculations, experimental measurements and the two-step chemical potential gradient model. To investigate the influence of different conditions on the thermodynamic driving force of SMX crystal growth, SMX solubilities in different polymer solutions were studied. Four model polymers effectively improved SMX solubility. It was further found that polyvinylpyrrolidone (PVP) and hydroxypropyl methyl cellulose (HPMC) played a crucial role in inhibiting SMX crystal growth. However, polyethylene glycol (PEG) promoted SMX crystal growth. The effect of the polymer on the crystal growth mechanisms of SMX was further analyzed by the two-step chemical potential gradient model. In the system containing PEG 6000, crystal growth is dominated by the surface reaction. However, in the system containing PEG 20000, crystal growth is dominated by both the surface reaction and diffusion. In addition, DFT calculations results showed that HPMC and PVP could form strong and stable binding energies with SMX, indicating that PVP and HPMC had the potential ability to inhibit SMX crystal growth.

关键词： insoluble drugs     polymer     inhibition crystallization     crystal growth kinetics     DFT calculations    

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Combustion characteristics and kinetics of bio-oil

Ruixia ZHANG, Zhaoping ZHONG, Yaji HUANG

《化学科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 119-124 doi: 10.1007/s11705-009-0068-x

摘要： The combustion characteristics of bio-oils derived from rice husk and corn were studied by thermogravimetry analysis. According to the thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) curves of bio-oils in air and nitrogen atmosphere, we analyzed the combustion characteristics of different kinds of bio-oils in different atmospheres and worked out the combustion kinetics parameters of the bio-oil, providing reliable base data for the burning of bio-oil. The thermogravimetry indicated that the combustion process of bio-oil was divided into three stages. At the same time, the combustion process can be described by different order reaction models, and with the method of Coats-Redfern, the activation energy and frequency factor of different kinds of bio-oils were obtained.

关键词： bio-oil     combustion characteristics     combustion kinetics    

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Thermal degradation kinetics and lifetime estimation for polycarbonate/polymethylphenylsilsesquioxane

Jiangbo WANG, Zhong XIN

《化学科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 167-171 doi: 10.1007/s11705-009-0006-y

摘要： The thermal degradation behaviors of polycarbonate/polymethylphenylsilsesquioxane (FRPC) composites were investigated by thermogravimetric analysis (TGA) under isothermal conditions in nitrogen atmosphere. The isothermal kinetics equation was used to describe the thermal degradation process. The results showed that activation energy ( ), in the case of isothermal degradation, was a quick increasing function of conversion (α) for polycarbonate (PC) but was a strong and decreasing function of conversion for FRPC. Under the isothermal condition, the addition of polymethylphenylsilsesquioxane (PMPSQ) retardanted the thermal degradation and enhanced the thermal stability of PC during the early and middle stages of thermal degradation. It also indicated a possible existence of a difference in nucleation, nuclei growth, and gas diffusion mechanism in the thermal degradation process between PC and FRPC. Meanwhile, the addition of PMPSQ influenced the lifetime of PC, but the composite still met the demand in manufacturing and application.

关键词： polycarbonate     polymethylphenylsilsesquioxane     thermal degradation kinetics     activation energy     lifetime    

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Influence of extracellular polymeric substances from activated sludge on the aggregation kinetics of

《环境科学与工程前沿（英文）》 2022年 第16卷 第2期 doi: 10.1007/s11783-021-1450-2

摘要：

• The NPs aggregation in the electrolyte solution is consistent with the DLVO theory.

关键词： Silver nanoparticles     Silver sulfide nanoparticles     Extracellular polymeric substances     Aggregation kinetics     Influence mechanisms    

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Preparation and crystallization kinetics of micron-sized Mg(OH)

Xingfu SONG, Kefeng TONG, Shuying SUN, Ze SUN, Jianguo YU

《化学科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 130-138 doi: 10.1007/s11705-013-1332-7

摘要： Magnesium hydroxide is an important chemical, and is usually obtained from seawater or brine via precipitation process. The particle size distribution of magnesium hydroxide has great effects on the subsequent filtration and drying processes. In this paper, micron-sized magnesium hydroxide with high purity, large particle size and low water content in filter cake was synthesized via simple wet precipitation in a mixed suspension mixed product removal (MSMPR) crystallizer. The effects of reactant concentration, residence time and impurities on the properties of magnesium hydroxide were investigated by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Malvern laser particle size analyzer. The results show that NaOH concentration and residence time have great effects on the water content and particle size of Mg(OH) . The spherical Mg(OH) with uniform diameter of about 30 μm was obtained with purity higher than 99% and water content less than 31%. Furthermore, the crystallization kinetics based on the population balance theory was studied to provide the theoretical data for industrial enlargement, and the simulation coefficients ( ) based on ASL model and C-R model are 0.9962 and 0.9972, respectively, indicating that the crystal growth rate of magnesium hydroxide can be well simulated by the size-dependent growth models.

关键词： magnesium hydroxide     precipitation     micron-sized     crystallization kinetics    

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Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles

Xuantao Wu, Jie Wang

《化学科学与工程前沿（英文）》 2019年 第13卷 第2期   页码 415-426 doi: 10.1007/s11705-018-1725-8

摘要： Catalytic steam gasification of fine coal char particles was carried out using a self-made laboratory reactor to determine the intrinsic kinetics and external diffusion under varying pressures (0.1–0.5 MPa) and superficial gas flow velocities (GFVs) of 13.8–68.8 cm?s . In order to estimate the gas release rate at a low GFV, the transported effect of effluent gas on the temporal gasification rate pattern was simulated by the Fluent computation and verified experimentally. The external mass transfer coefficients ( ) and the effectiveness factors were determined at lower GFVs, based on the intrinsic gasification rate obtained at a high GFV of 55.0 cm?s . The was found to be almost invariable in a wider carbon conversion of 0.2–0.7. The variations of at a median carbon conversion with GFV, temperature and pressure were found to follow a modified Chilton-Colburn correlation: (0.04< <0.19), where is total pressure and is atmospheric pressure. An intrinsic kinetics/external diffusion integrating model could well describe the gasification rate as a function of GFV, temperature and pressure over a whole gasification process.

关键词： coal char     catalytic steam gasification     pressure     kinetics     diffusion    

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标题 作者 时间 类型 操作

Modeling the aqueous reaction kinetics of estriol with ferrate

Cong LI, Naiyun GAO

期刊论文

Kinetics of oxidation of dimethyl trisulfide by potassium permanganate in drinking water

Xiaoyan MA, Shifei HU, Hongyu WANG, Jun LI, Jing HUANG, Yun ZHANG, Weigang LU, Qingsong LI

期刊论文

Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partialoxidation of methane

期刊论文

Ozonation of the 5-fluorouracil anticancer drug and its prodrug capecitabine: Reaction kinetics, oxidation

Siyu Chen, Lee Blaney, Ping Chen, Shanshan Deng, Mamatha Hopanna, Yixiang Bao, Gang Yu

期刊论文

Product identification and toxicity change during oxidation of methotrexate by ferrate and permanganate

期刊论文

Characterization of value-added chemicals derived from the thermal hydrolysis and wet oxidation of sewage

Milan Malhotra, Anurag Garg

期刊论文

Kinetics of microwave-enhanced oxidation of phenol by hydrogen peroxide

Deming ZHAO, Jie CHENG, Michael R. HOFFMANN

期刊论文

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

期刊论文

Accelerated degradation of orange G over a widepH range in the presence of FeVO

Xiaoxia Ou, Jianfang Yan, Fengjie Zhang, Chunhua Zhang

期刊论文

Theoretical insights into influence of additives on sulfamethoxazole crystal growth kinetics and mechanisms

期刊论文

Combustion characteristics and kinetics of bio-oil

Ruixia ZHANG, Zhaoping ZHONG, Yaji HUANG

期刊论文

Thermal degradation kinetics and lifetime estimation for polycarbonate/polymethylphenylsilsesquioxane

Jiangbo WANG, Zhong XIN

期刊论文

Influence of extracellular polymeric substances from activated sludge on the aggregation kinetics of

期刊论文

Preparation and crystallization kinetics of micron-sized Mg(OH)

Xingfu SONG, Kefeng TONG, Shuying SUN, Ze SUN, Jianguo YU

期刊论文

Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles

Xuantao Wu, Jie Wang

期刊论文