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Simultaneous generation of free radicals, Fe(IV) and Fe(V) by ferrate activation: A review

CHEMICAL engineering JOURNAL 2024年 481卷

作者： Dong, Feilong Fu, Chuyun Feng, Mingbao Wang, Da Song, Shuang Li, Cong Lichtfouse, Eric Li, Jinzhe Lin, Qiufeng Sharma, Virender K. Zhejiang Univ Technol Coll Environm Hangzhou 310014 Peoples R China Xiamen Univ Coll Environm & Ecol Xiamen 361100 Peoples R China Univ Shanghai Sci & Technol Sch Environm & Architecture Shanghai 200433 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Montclair State Univ Dept Earth & Environm Studies Montclair NJ 07043 USA Texas A&M Univ Sch Publ Hlth Dept Environm & Occupat Hlth Program Environm & Sustainabil 212 Adriance Lab Rd1266 TAMU College Stn TX 77843 USA

Ferrate (FeVIO42-, Fe(VI)) is a green and effective oxidant that has been extensively studied for removing organic pollutants in water and wastewater. However, practical applications of ferrate are limited due to selfdecomposition at nearly neutral pH and low removal efficiency for electron-deficient pollutants. Therefore, recent research has focused on activating Fe(VI). Although various methods for enhancing Fe(VI) oxidation efficacy have been explored and reviewed extensively, there remains a gap in the systematic comparison of the different highly reactive species involved in the Fe(VI) activation process. To bridge this gap, this review aims to comprehensively present the mechanisms, strategies, and efficiencies of generating key reactive species, including sulfate radicals (SO4 center dot-), hydroxyl radicals (center dot OH), and intermediate iron species (Fe(IV) and Fe(V)), in the Fe(VI) activation system. We observed that both iron intermediates and free radicals react at much higher rate constants than their Fe(VI) precursor, resulting in rapid abatement of organic pollutants. The oxidation characteristics of these active species in Fe(VI) activation are discussed. Finally, the practicability of each Fe(VI) activating strategy is evaluated for rapid and efficient removal of organic pollutants in water and wastewater.

关键词： Ferrate High-valent iron intermediates Free radicals Activation Mechanism Degradation

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Passive decay heat removal system design for the integral inherent safety light water reactor (I²S-LWR)

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ANNALS OF NUCLEAR ENERGY 2020年 145卷 106987-106987页

作者： Wang, Mingjun Manera, Annalisa Petrov, Victor Memmott, Matthew J. Qiu, Suizheng Su, G. H. Xi An Jiao Tong Univ Dept Nucl Sci & Technol State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Univ Michigan Dept Nucl Engn & Radiol Sci Ann Arbor MI 48109 USA Brigham Young Univ 350 Clyde Bldg Provo UT 84602 USA

The Integral, Inherently Safe Light Water Reactor ((IS)-S-2-LWR) is an innovative Pressurized Water Reactor (PWR) concept being developed by a multi-institutional team led by Georgia Tech and in collaboration with Westinghouse, under the Department of Energy's Nuclear Energy University Programs Integrated Research Projects (DOE NEUP IRP). The University of Michigan leads the design of the thermal-hydraulic and passive safety systems, in collaboration with Westinghouse and Bringham Young University. The I2S-LWR features an integral primary system configuration and is more conducive to the implementation of inherent safety features by eliminating potential accidents. In this paper, a novel passive Decay Heat Removal System (DHRS), is presented, consisting of a primary loop, an intermediate loop and a cooling tower loop. This passive system is designed to remove the I2S-LWR decay heat in the case of emergency heat removal transients, without the need for external power or operator action. The proposed DHR uses atmosphere as ultimate heat sink, to achieve indefinite decay heat removal. In this paper, firstly, the design of primary and secondary DHRS heat exchangers is optimized. Then the DHR heat removal characteristics are studied using the best-estimate thermal hydraulic code RELAP5. In addition, CFD simulations have been performed in order to investigate the DRHS helical coil primary heat exchanger performance with different coil pipe arrangements, and optimize its design. The performance of the proposed DHRS concept is investigated in case of a Station Black-Out (SBO) scenario. Operation of two, three and four DHRS trains is studied respectively. The results show that three out of four DHRS trains are sufficient to indefinitely remove the core decay heat successfully during a SBO, and keep the reactor in a safe state without the need of any other auxiliary active system. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： DHR Integral reactor Station Black-Out Heat removal

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Obstacles of solar-powered photocatalytic water splitting for hydrogen production: A perspective from energy flow and mass flow

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ENERGY 2019年 172卷 1079-1086页

作者： Guo, Liejin Chen, Yubin Su, Jinzhan Liu, Maochang Liu, Ya Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

Solar-driven photocatalytic water splitting for hydrogen production has emerged as one of the foremost scientific issues. However, the efficient, low-cost, and large-scale operable system is still missing. Photocatalytic water splitting has multiple processes that involve light absorption, charge excitation and transfer, mass transfer, and chemical reaction, making it extremely complicated and challenging. Herein, we review the whole-process photocatalytic water splitting from two kinds of "flow": energy flow and mass flow. The energy flow represents transmission and conversion of solar energy through the concentrator, reactor, reaction solution, and photocatalyst. The mass flow refers to transfer of reactants and products in the gas-liquid-solid multiphase environment. For the first time, we clearly describe the energy flow and mass flow in photocatalytic water splitting from multiple spatiotemporal scales, and point out that the low efficiencies of photocatalytic water splitting are attributed to obstacles in energy flow and mass flow, as well as non-coupling and mismatching of energy flow and mass flow. The mechanistic insights learned from this perspective indicate that, in addition to the material optimization, the scientific and engineered design of sunlight collection, interfacial reaction, and mass transfer is of great significance. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Solar energy Hydrogen production Photocatalytic water splitting Energy flow Mass flow

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Enhanced viscoelastic focusing of particle in microchannel

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ELECTROPHORESIS 2020年第10-11期41卷 973-982页

作者： Fan, Liang-Liang Zhao, Zhi Tao, Yi-Yi Wu, Xu Yan, Qing Zhe, Jiang Zhao, Liang Xi An Jiao Tong Univ Sch Mech Engn Xian Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Univ Akron Dept Mech Engn Akron OH 44325 USA

A novel method is reported to enhance the focusing of microparticle in the viscoelastic fluid. Gradually contracted geometry is designed in microchannel, which changes the distribution of the elastic lift force on the cross section. Additionally, it induces the viscous drag force and the Saffman lift force in the lateral direction. Under the combined effect of these forces, microparticles fast migrate to the center of the channel. In comparison to the channel with constant cross section, the present channel significantly enhances the particle's lateral migration, leading to efficient viscoelastic particle focusing in a short channel length. The influence of flow rate, channel length, particle size and fluid property on the particle focusing is also investigated. With simple structure, small footprint and perfect particle focusing performance, the present device has great potential in the particle focusing processes in various lab-on-a-chip applications.

关键词： Elastic lift force lab chip Microfluidic Particle focusing Viscous drag force

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Modulating charge centers and vacancies in P-CoNi loaded phosphorus-doped ZnIn2S4 nanosheets for H2 and H2O2 photosynthesis from pure water

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NANO ENERGY 2023年 117卷

作者： Xue, Fei Zhang, Chunyang Peng, Huiping Sun, Lin Yan, Xueli Liu, Feng Wu, Wentong Liu, Maochang Liu, Liangbin Hu, Zhiwei Kao, Cheng-Wei Chan, Ting-Shan Xu, Yong Huang, Xiaoqing Xiamen Univ Coll Chem & Chem Engn State Key Lab Phys Chem Solid Surfaces Xiamen 361005 Peoples R China Guangdong Univ Technol Sch Mat & Energy Collaborat Innovat Ctr Adv Energy Mat Guangzhou Key Lab Low Dimens Mat & Energy Storage Guangzhou 510006 Peoples R China Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Max Planck Inst Chem Phys Solids Nothnitzer Str 40 D-01187 Dresden Germany Natl Synchrotron Radiat Res Ctr 101 Hsin Ann Rd Hsinchu 30076 Taiwan Innovat Lab Sci & Technol Energy Mat Fujian Prov I Xiamen 361005 Peoples R China

Photocatalytic water splitting has recently attracted increasing interests for solar to chemical energy conversion. Nevertheless, the high-efficiency process for photocatalytic water splitting is driven by recombination of photogenerated electron-hole pairs and the resultant low H2 productivity. Herein, we demonstrate that P-doping induced positive charge centers (P delta+) and indium vacancies (VIn) in ZnIn2S4 (ZIS) nanosheets can significantly promote photosplitting pure water to simultaneously produce H2 and H2O2. Microstructural and spectroscopic analysis suggest that P delta+ and VIn can trap photogenerated electrons and holes, respectively, as a result of enhanced separation of electron-hole pairs. The optimal catalyst of P-CoNi/ZIS displays a stoichiometric H2 and H2O2 productivity of 1228.7 and 1105.5 mu mol h-1 g-1, respectively, with an apparent quantum efficiency of 6.2% at 365 nm. Impressively, H2 productivity of P-CoNi/ZIS has surpassed most reported catalysts for photocatalytic pure water splitting. This work provides a unique strategy to create efficient photocatalyst for pure water splitting.

关键词： In vacancy P doping Pure water splitting

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Taming NO oxidation efficiency by γ-MnO2morphology regulation

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CATALYSIS SCIENCE & TECHNOLOGY 2020年第17期10卷 5996-6005页

作者： Chen, Lei Zhang, Jinping Li, Yuxin Wu, Xiaomei Zhang, Zaoxiao Lu, Qiang He, Chi Xi An Jiao Tong Univ Sch Chem Engn & Technol Shaanxi Key Lab Energy Chem Proc Intensificat Xian Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian Peoples R China Xi An Jiao Tong Univ Sch Energy & Power Engn Key Lab Thermofluid Sci & Engn MOE Xian 710049 Peoples R China North China Elect Power Univ Natl Engn Lab Biomass Power Generat Equipment Beijing 102206 Peoples R China Univ Chinese Acad Sci Natl Engn Lab VOCs Pollut Control Mat & Technol Beijing 101408 Peoples R China

Nitric oxide (NO) emitted from the combustion of fossil fuels has drawn global concern, and the oxidation of NO contributes greatly to the DeNO(x)process. Herein, single-crystal gamma-MnO(2)catalysts with well-defined hollow-sphere-, sea-urchin-, and flower-like morphologies (gamma-MnO2-HS, gamma-MnO2-SU, and gamma-MnO2-F) were rationally designed and synthesizedviaan environmental-friendly template-free hydrothermal strategy. The physicochemical properties of the prepared materials were characterized by XRD, FE-SEM, TEM, BET, XPS, H-2-TPR, O-2/NO-TPD andin situDRIFTS, and their catalytic activities in NO oxidation were evaluated. The results showed the gamma-MnO2-HS sample possessed the highest activity and could oxidize 91.1% of NO at 275 degrees C, which was obviously higher than those of the gamma-MnO2-SU and gamma-MnO2-F catalysts. It was found that the presence of abundant surface-adsorbed oxygen and the largest quantity of Mn(3+)over the gamma-MnO2-HS material respectively accelerated the processes of NO adsorption and O(2)activation, which greatly promoted the NO oxidation process. This work provides significant insights into NO oxidation over gamma-MnO(2)catalysts.

关键词： Nitric oxide

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Study on the surface structure development of porous char particles in catalytic supercritical water gasification process

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FUEL PROCESSING TECHNOLOGY 2019年 193卷 73-81页

作者： Fan, Chao Jin, Hui Shang, Fei Feng, Huifang Sun, Jingli Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn SKLMF 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China

Porous structure and its development have significant influence on the heat and mass transfer between char particle and surrounding fluid, and the unique properties of supercritical water might make this process different. In this work, the catalytic supercritical water gasification experiments of semi-coke were conducted with K2CO3 as the catalyst at 650 degrees C to 750 degrees C, and the porous structure was characterized by nitrogen adsorption and SEM. Both micropores of 1.8 nm and mesopores that were enlarged in the gasification process were detected. K2CO3 addition was found to obviously promote the development of mesopore structure, while temperature had no obvious influence on structure development. Specific surface area and pore volume increased after gasification by one to two orders of magnitude, most up to 600 m(2).g(-1) and 0.57 cm(3).g(-1), respectively. Fractal dimension D increased sharply firstly due to the formation of a large amount of pores in the initial stage and then began to decrease because of the plasticity of char. The obtained structure evolution rules would be used for the establishment and optimization of kinetic models and the study of heat and mass transfer characteristics between char particle and surrounding fluid.

关键词： Supercritical water gasification Porous structure Catalyst Nitrogen adsorption

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Local degradation in proton exchange membrane fuel cells with dead-ended anode

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JOURNAL OF power SOURCES 2020年 477卷 229021-229021页

作者： Yang, Yupeng Zhang, Xu Guo, Liejin Liu, Hongtan Xidian Univ Key Lab Elect Equipment Struct Design Minist Educ Xian 710071 Shaanxi Peoples R China Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Univ Miami Clean Energy Res Inst Dept Mech & Aerosp Engn Coral Gables FL 33124 USA

The dead-ended anode (DEA) configuration can simplify proton exchange membrane fuel cell (PEMFC) systems and reduce system cost. However, the DEA configuration can also accelerate fuel cell degradation during long-term operations. Understanding the degradation mechanisms is crucial to improve fuel cell durability. In this study, experiments are performed to investigate the local degradation phenomena in PEMFCs during DEA operations. The detailed degradation mechanisms are revealed through various electrochemical analysis. The local polarization curves show that the local fuel cell performance decreases are very non-uniform and the inlet area suffers the most severe performance decrease. Electrochemical measurements indicate that the most serious carbon corrosion in catalyst layer occurs near the anode outlet. However, the most severe local membrane degradation is observed near the anode inlet. Furthermore, we observe that the pressure swing anode supply mode can significantly mitigate fuel cell degradation during DEA operation. The water and gas distributions in the anode are much more uniform with the periodical oscillatory flow under pressure swing mode, reducing local membrane dehydration and avoiding local hydrogen starvation. Thus, both the local membrane degradation and local carbon corrosion are significantly mitigated under the pressure swing mode.

关键词： Proton exchange membrane fuel cell Dead-ended anode Local degradation Pressure swing

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Microscale drag model considering the effect of interface between dense and dilute phases for gas-solid suspensions at moderate Reynolds numbers

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INTERNATIONAL JOURNAL OF multiphase flow 2022年 157卷

作者： Ma, Teng Li, Yu Zhou, Qiang Chen, Xiao Xi An Jiao Tong Univ Sch Chem Engn & Technol Xian 710049 Shaanxi Peoples R China Univ Shaanxi Prov Engn Res Ctr New Energy Syst Engn & Equipment Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

Particle-resolved direct numerical simulations of flows past various fixed structures of spheres are performed to study the drag force at local Reynolds numbers up to 250. At the gas-solid interface, the drag force is found to be 5% similar to 800% of that estimated by BVK law (Beetstra et al. AIChE Journal, 2007, 53(2):489-501) at different particle Reynolds numbers and solid volume fraction gradients. Thus a microscale drag model at the cluster interface is developed as a function of the particle Reynolds number and the solid concentrations of dense and dilute phases. Assessments of the proposed drag model are performed with direct numerical simulations of flows past plug-like, spherical, ellipsoidal clusters as well as bubble-containing structures. The results show that the new model well captures the drag variations at microscales of several sphere diameters and correlates well with the solid concentrations and velocities of dense and dilute phases.

关键词： Gas-solid flows The drag force Particle-resolved direct numerical simulations Clusters of particles

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PORE STRUCTURE AND ITS EVOLUTION IN CHAR DURING SUPERCRITICAL WATER GASIFICATION PROCESS

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JOURNAL OF POROUS MEDIA 2019年第2期22卷 195-207页

作者： Jin, Hui Fan, Chao Guo, Liejin Zhao, Xiao Cao, Changqing Wei, Wenwen Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn SKLMF 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China

Pore structure and its evolution provide key information for the heat and mass transfer in char particles and are important for supercritical water gasification reactor design. Supercritical water gasification was conducted in an autoclave, and nitrogen adsorption and scanning electron microscopy were applied for pore characterization in char. Specific surface area and pore volume showed an increasing tendency, but the growth of the specific surface area obviously slowed down as the reaction proceeded. Micropores with pore size of about 1.8 nm in original char increased obviously in quantity but remained nearly constant in size in the gasification process, whereas mesopores showed an increasing trend in both quantity and size from 3 to 5.5 nm. The surface fractal dimension calculated through the Frenkel-Halsey-Hill equation increased first and then decreased. These evolution characteristics may provide useful information for the establishment and optimization of kinetic models for supercritical water gasification.

关键词： supercritical water gasification nitrogen adsorption pore structure fractal dimension

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