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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    

Effects of humic acid and surfactants on the aggregation kinetics of manganese dioxide colloids

Xiaoliu HUANGFU,Yaan WANG,Yongze LIU,Xixin LU,Xiang ZHANG,Haijun CHENG,Jin JIANG,Jun MA

《环境科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 105-111 doi: 10.1007/s11783-014-0726-1

摘要: The aggregation of common manganese dioxide (MnO ) colloids has great impact on their surface reactivity and therefore on their fates as well as associated natural and synthetic contaminants in engineered (e.g. water treatment) and natural aquatic environments. Nevertheless, little is known about the aggregation kinetics of MnO colloids and the effect of humic acid (HA) and surfactants on these. In this study, the early stage aggregation kinetics of MnO nanoparticles in NaNO and Ca(NO ) solutions in the presence of HA and surfactants (i.e., sodium dodecyl sulfate (SDS), and polyvinylpyrrolidone (PVP)) were modeled through time-resolved dynamic light scattering. In the presence of HA, MnO colloids were significantly stabilized with a critical coagulation concentration (CCC) of ~300 mmol·L NaNO and 4 mmol·L Ca(NO ) . Electrophoretic mobility (EPM) measurements confirmed that steric hindrance may be primarily responsible for increasing colloidal stability in the presence of HA. Moreover, the molecular and/or chemical properties of HA might impact its stabilizing efficiency. In the case of PVP, only a slight increase of aggregation kinetics was observed, due to steric reactions originating from adsorbed layers of PVP on the MnO surface. Consequently, higher CCC values were obtained in the presence of PVP. However, there was a negligible reduction in MnO colloidal stability in the presence of 20 mg·L SDS.

关键词: humic acid     surfactant     aggregation kinetics     drinking water     manganese dioxide colloids    

Synthesis and ultraviolet/aggregation-induced emission investigation of novel tetraphenylvinyl hydrazone

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2061-2073 doi: 10.1007/s11705-023-2366-0

摘要: Herein, three novel tetraphenylethylene hydrazone chemosensors TC12, SC16, and TC16 are prepared for the selective detection of F. Two NH and one C=N units are incorporated into the sensors for better colorimetric responses, whereas the tetraphenyl unit is in charge of the aggregation-induced emission effect. Among them, compounds SC16 and TC16 form stable gels with some organic solvents. All the tetrahydrofuran/H2O solutions of the three compounds exhibit aggregation-induced emission effect, whereby the fluorescence emission increases by varying degrees with the volume of poor solvent water. Moreover, good aggregation-induced emission effects are observed in the self-assembly of SC16 and TC16. As a sample chemosensor, TC12 in tetrahydrofuran responds to F selectively with high sensitivity, with the colorimetric and fluorometric detection limits of 8.25 × 10−7 mol·L–1 and 2.69 × 10−7 mol·L–1, respectively. The reversible gel-sol-gel phase transition and color changes indicate that both SC16-dimethyl sulfoxide and TC16-ethyl acetate gels specifically respond to F with good sensitivity. The detection results are well supported by ultraviolet-visible spectroscopy, fluorescent spectroscopy, and 1H nuclear magnetic resonance. More importantly, the driving forces of gelation are visually clarified through the single crystal X-ray analysis of compound TOMe.

关键词: organogelator     tetraphenylvinyldrazone     single crystal     aggregation-induced emission effect     ion sensing    

Trapezoidal Intuitionistic Fuzzy Aggregation Operator Based on Choquet Integral and Its Application to

Xi-hua Li,Xiao-hong Chen

《工程管理前沿(英文)》 2015年 第2卷 第3期   页码 266-276 doi: 10.15302/J-FEM-2015048

摘要: The Choquet integral can serve as a useful tool to aggregate interacting criteria in an uncertain environment. In this paper, a trapezoidal intuitionistic fuzzy aggregation operator based on the Choquet integral is proposed for multi-criteria decision-making problems. The decision information takes the form of trapezoidal intuitionistic fuzzy numbers and both the importance and the interaction information among decision-making criteria are considered. On the basis of the introduction of trapezoidal intuitionistic fuzzy numbers, its operational laws and expected value are defined. A trapezoidal intuitionistic fuzzy aggregation operator based on the Choquet integral is then defined and some of its properties are investigated. A new multi-criteria decision-making method based on a trapezoidal intuitionistic fuzzy Choquet integral operator is proposed. Finally, an illustrative example is used to show the feasibility and availability of the proposed method.

关键词: multi-criteria decision making     trapezoidal intuitionistic fuzzy numbers     Choquet integral     fuzzy measure     aggregation operator    

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    

Controlling interstory drift ratio profiles via topology optimization strategies

《结构与土木工程前沿(英文)》 2023年 第17卷 第2期   页码 165-178 doi: 10.1007/s11709-022-0892-3

摘要: An approach to control the profiles of interstory drift ratios along the height of building structures via topology optimization is proposed herein. The theoretical foundation of the proposed approach involves solving a min–max optimization problem to suppress the maximum interstory drift ratio among all stories. Two formulations are suggested: one inherits the bound formulation and the other utilizes a p-norm function to aggregate all individual interstory drift ratios. The proposed methodology can shape the interstory drift ratio profiles into inverted triangular or quadratic patterns because it realizes profile control using a group of shape weight coefficients. The proposed formulations are validated via a series of numerical examples. The disparity between the two formulations is clear. The optimization results show the optimal structural features for controlling the interstory drift ratios under different requirements.

关键词: interstory drift ratio     aggregation function     bound formulation     min–max problem     topology optimization    

Protein aggregation in association with delayed neuronal death in rat model of brain ischemia

GE Pengfei, FU Shuanglin, LI Wenchen, WANG Chonghao, ZHOU Chuibing, LUO Yinan, LUO Tianfei

《医学前沿(英文)》 2008年 第2卷 第1期   页码 70-74 doi: 10.1007/s11684-008-0013-2

摘要: To investigate the relationship between protein aggregation and delayed neuronal death, we adopted rat models of 20 min ischemia. Brain ischemia was produced using the 2-vessel occlusion (2VO) model in rats Light microscopy, transmission electronic microscopy and Western blot analysis were performed for morphological analysis of neurons, and protein detection. The results showed delayed neuronal death took place at 72 h after ischemia-reperfusion, protein aggregates formed at 4 h after reperfusion and reached the peak at 24 h after reperfusion, and Western blot analysis was consistent with transmission electronic microscopy. We conclude that protein aggregation is one of the important factors leading to delayed neuronal death.

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    

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    

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    

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    

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    

Determination of growth kinetics of microorganisms linked with 1,4-dioxane degradation in a consortium

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-022-1567-y

摘要:

● Evaluated three methods for determining the consortia’s growth kinetics.

关键词: Biodegradation     1     4-Dioxane     Kinetics     Microbial consortium     16S rRNA    

Novel approach to control adsorbent aggregation: iron fixed bentonite-fly ash for Lead (Pb) and Cadmium

Teza Mwamulima, Xiaolin Zhang, Yongmei Wang, Shaoxian Song, Changsheng Peng

《环境科学与工程前沿(英文)》 2018年 第12卷 第2期 doi: 10.1007/s11783-017-0979-6

摘要: In the present study, a novel approach was used to control zero valent iron aggregation and separation problems by fixing zero valent iron (ZVI) on bentonite-fly ash pellets. For this purpose, porous low cost bentonite-fly ash (BFA) pellets with size of 2.00 cm in length and 0.35 cm in diameter were prepared and fixed with ZVI to manufacture zero valent iron bentonite-fly ash (ZVI-BFA) pellets. Importantly, unlike powdered adsorbents, ZVI-BFA can easily be separated from final effluents when exhausted without any disintegration. The performance of the developed novel adsorbent was investigated for the removal of Pb and Cd from aqueous media. At 100 mg·L and 1 g adsorbent, a maximum of 89.5% of Cd and 95.6% of Pb was removed by ZVI-BFA as compared to 56% and 95% removal by BFA. At 200 mg·L , Cd and Pb removal by ZVI-BFA was 56% and 99.8% respectively as compared to only 28% and 96% by BFA. Further, the removal kinetics was best fitted for pseudo-second order model. The study provides the basis for improving the removal capacity of porous materials by iron fixation while taking separation ability into consideration.

关键词: Zero valent iron     Bentonite     Fly ash     Heavy metals removal     Synthesis    

Performance and kinetics of iron-based oxygen carriers reduced by carbon monoxide for chemical looping

Xiuning HUA,Wei WANG,Feng WANG

《环境科学与工程前沿(英文)》 2015年 第9卷 第6期   页码 1130-1138 doi: 10.1007/s11783-015-0821-y

摘要: Chemical looping combustion is a promising technology for energy conversion due to its low-carbon, high-efficiency, and environmental-friendly feature. A vital issue for CLC process is the development of oxygen carrier, since it must have sufficient reactivity. The mechanism and kinetics of CO reduction on iron-based oxygen carriers namely pure Fe O and Fe O supported by alumina (Fe O /Al O ) were investigated using thermo-gravimetric analysis. Fe O /Al O showed better reactivity over bare Fe O toward CO reduction. This was well supported by the observed higher rate constant for Fe O /Al O over pure Fe O with respective activation energy of 41.1±2.0 and 33.3±0.8 kJ·mol . The proposed models were compared via statistical approach comprising Akaike information criterion with correction coupled with F-test. The phase-boundary reaction and diffusion control models approximated to 95% confidence level along with scanning electron microscopy results; revealed the promising reduction reactions of pure Fe O and Fe O /Al O . The boosting recital of iron-based oxygen carrier support toward efficient chemical looping combustion could be explained accurately through the present study.

关键词: chemical looping combustion     iron-based oxygen carriers     reduction kinetics     carbon monoxide     statistics    

标题 作者 时间 类型 操作

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

期刊论文

Effects of humic acid and surfactants on the aggregation kinetics of manganese dioxide colloids

Xiaoliu HUANGFU,Yaan WANG,Yongze LIU,Xixin LU,Xiang ZHANG,Haijun CHENG,Jin JIANG,Jun MA

期刊论文

Synthesis and ultraviolet/aggregation-induced emission investigation of novel tetraphenylvinyl hydrazone

期刊论文

Trapezoidal Intuitionistic Fuzzy Aggregation Operator Based on Choquet Integral and Its Application to

Xi-hua Li,Xiao-hong Chen

期刊论文

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

期刊论文

Controlling interstory drift ratio profiles via topology optimization strategies

期刊论文

Protein aggregation in association with delayed neuronal death in rat model of brain ischemia

GE Pengfei, FU Shuanglin, LI Wenchen, WANG Chonghao, ZHOU Chuibing, LUO Yinan, LUO Tianfei

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

Modeling the aqueous reaction kinetics of estriol with ferrate

Cong LI, Naiyun GAO

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

Determination of growth kinetics of microorganisms linked with 1,4-dioxane degradation in a consortium

期刊论文

Novel approach to control adsorbent aggregation: iron fixed bentonite-fly ash for Lead (Pb) and Cadmium

Teza Mwamulima, Xiaolin Zhang, Yongmei Wang, Shaoxian Song, Changsheng Peng

期刊论文

Performance and kinetics of iron-based oxygen carriers reduced by carbon monoxide for chemical looping

Xiuning HUA,Wei WANG,Feng WANG

期刊论文