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Comparison of UV-based advanced oxidation processes for the removal of different fractions of NOM from drinking water

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Journal of Environmental Sciences 2023年第4期126卷 387-395页

作者： Zhenxing Yao Mingquan Wang Ruibao Jia Qinghua Zhao Li Liu Shaohua Sun Shandong Province City water supply and Drainage water Quality Monitoring center Jinan 250101China

This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced oxidation processes (AOPs).The changing characteristics of NOM were evaluated by dissolved organic carbon (DOC),the specific UV absorbance (SUVA),trihalomethanes formation potential (THMFP),organic halogen adsorbable on activated carbon formation potential (AOXFP) and parallel factor analysis of excitation–emission matrices (PARAFAC-EEMs).In the three UV-based AOPs,HPI fraction with low molecular weight and aromaticity was more likely to degradate than HPO and TPI,and the removal efficiency of SUVA for HPO was much higher than TPI and HPI *** terms of the specific THMFP of HPO,TPI and HPI,a reduction was achieved in the UV/H_(2)O_(2)process,and the higest removal rate even reached to 83%.UV/TiO_(2)and UV/PS processes can only decrease the specific THMFP of *** specific AOXFP of HPO,TPI and HPI fractions were all able to be degraded by the three UV-based AOPs,and HPO content is more susceptible to decompose than TPI and HPI ***/H_(2)O_(2)was found to be the most effective treatment for the removal of THMFP and AOXFP under given conditions.C1 (microbial or marine derived humic-like substances),C_(2) (terrestrially derived humic-like substances)and C_(3) (tryptophan-like proteins) fluorescent components of HPO fraction were fairly labile across the UV-based AOPs treatment.C_(3) of each fraction of NOM was the most resistant to degrade upon the UV-based *** from this study may provide the prediction about the consequence of UV-based AOPs for the degradation of different fractions of NOM with varied characteristics.

关键词： Advanced oxidation processes Natural organic matter Trihalomethanes Organic halogen adsorbable on activated carbon Parallel factor analysis

The emerging role of nitric oxide in the synaptic dysfunction of vascular dementia

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Neural Regeneration Research 2025年第2期20卷 402-415页

作者： Xiaorong Zhang Zhiying Chen Yinyi Xiong Qin Zhou Ling-Qiang Zhu Dan Liu Department of Pathology Affiliated Hospital of Jiujiang UniversityJiujiangJiangxi ProvinceChina Jiujiang Clinical Precision Medicine Research center JiujiangJiangxi ProvinceChina center for Cognitive Science and Transdisciplinary studies Jiujiang UniversityJiangxi ProvinceChina Department of Neurology Affiliated Hospital of Jiujiang UniversityJiujiangJiangxi ProvinceChina Department of Rehabilitation Affiliated Hospital of Jiujiang UniversityJiujiangJiangxi ProvinceChina Department of Pathophysiology School of Basic MedicineTongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei ProvinceChina

With an increase in global aging,the number of people affected by cerebrovascular diseases is also increasing,and the incidence of vascular dementia-closely related to cerebrovascular risk-is increasing at an epidemic ***,few therapeutic options exist that can markedly improve the cognitive impairment and prognosis of vascular dementia *** in Alzheimer’s disease and other neurological disorders,synaptic dysfunction is recognized as the main reason for cognitive *** oxide is one of the ubiquitous gaseous cellular messengers involved in multiple physiological and pathological processes of the central nervous ***,nitric oxide has been implicated in regulating synaptic plasticity and plays an important role in the pathogenesis of vascular *** review introduces in detail the emerging role of nitric oxide in physiological and pathological states of vascular dementia and summarizes the diverse effects of nitric oxide on different aspects of synaptic dysfunction,neuroinflammation,oxidative stress,and blood-brain barrier dysfunction that underlie the progress of vascular ***,we propose that targeting the nitric oxide-sGC-cGMP pathway using certain specific approaches may provide a novel therapeutic strategy for vascular dementia.

关键词： endoplasmic reticulum stress endothelial nitric oxide synthase gene therapy nitric oxide NO-sGC-cGMP pathway synaptic dysfunction vascular dementia

Sediment transport in pure acceleration-skewed oscillatory sheet flow

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Journal of Hydrodynamics 2018年第6期30卷 1045-1054页

作者： Xin Chen Fu-jun Wang Gen-fa Chen Liu-chao Qiu College of water Resources and Civil Engineering China Agricultural University Beijing Engineering Research center of Safety and Energy Saving Technology for water supply Network System China Agricultural University China Institute of water Resources and Hydropower Research

In the present study, an analytical concept model is built, using a two-phase model for the sediment transport in a pure acceleration-skewed oscillatory sheet flow. The analytical model is based on the asymmetric wave theory, the irregular boundary layer theory and the exponential concentration distribution theory, to be used for analyzing the phase lag and the boundary layer development related to the acceleration skewness. The two-phase model is applied for the calculations of the instantaneous erosion depth, the sediment flux, the boundary layer thickness and the sediment transport rate, as well as the differences between the positive acceleration stage and the negative acceleration stage caused by the acceleration skewness, as very important in the net current and sediment transport. The effects of the sediment diameter and the phase lag are explained by a comparison with the instantaneous type empirical formula, as is closely related to the acceleration skewness. With the analytical concept model and the two-phase model, the generation of the net sediment transport in the pure acceleration-skewed flows is clearly explained. The phase lag effect is important for the instantaneous sediment transport in the pure acceleration-skewed flow, whereas the boundary layer development difference between the positive acceleration stage and the negative acceleration stage plays a major role in the determination of the net sediment transport.

关键词： Acceleration skewness analytical concept model boundary layer thickness two-phase model sediment transport rate

A general two-phase mixture model for sediment-laden flow in open channel

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Journal of Hydrodynamics 2022年第2期34卷 286-298页

作者： Jia-xing Li Xin Chen Beijing Engineering Research center of Safety and Energy Saving Technology for water supply Network System China Agricultural UniversityBeijing100083China

This work extends the sediment-laden mixture model with consideration of the turbulence damping and particle wake effects under the framework of improved efficiency and *** mixture model consists of the continuity and momentum equations for the sediment-laden mixture,and the continuity equation for the sediment.A theoretical formula is derived for the relative velocity between the water and sediment phases,with consideration of the effects of the pressure gradient,the shear stress and the lift force.A modified expression of the particle wake effect,inducing the local turbulence enhancement around the sediment particle,is employed to improve the turbulent diffusion of the coarse *** k_(m)-ε_(m) model is proposed to close the mixture turbulence,with the turbulence damping effect due to the high sediment concentration expressed by the density-stratification term without an empirical *** k_(m)-ε_(m) turbulence model requires smaller computational work and offers better results than an empirical density-stratification turbulence model in high sediment concentration ***,with the proposed mixture model,the sediment transport in the open channel under a wide range of sediment sizes and concentrations can be revealed with the results in good agreement with experimental data for the velocity,the sediment concentration and the turbulent kinetic energy.

关键词： Sediment-laden flow two-phase mixture model particle wake effect turbulence damping effect density stratification

Long-term effects of silver nanoparticles on performance of phosphorus removal in a laboratory-scale vertical flow constructed wetland

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Journal of Environmental Sciences 2020年第1期32卷 319-330页

作者： Juan Huang Jun Xiao Yang Guo Wenzu Guan Chong Cao Chunni Yan Mingyu Wang School of Civil Engineering Southeast UniversityNanjing 211189China Security Support center for Urban water supply of Jiangsu Province Nanjing 210036China

Silver nanoparticles(AgNPs)have been widely used in many fields,which raised concerns about potential threats to biological sewage treatment *** this study,the phosphorus removal performance,enzymatic activity and microbial population dynamics in constructed wetlands(CWs)were evaluated under a long-term exposure to Ag NPs(0,50,and 200μg/L)for 450 *** have shown that Ag NPs inhibited the phosphorus removal efficiency in a short-term exposure,whereas caused no obviously negative effects from a long-term ***,in the coexisting CW system of Ag NPs and phosphorus,competition exhibited in the initial exposure phase,however,cooperation between them was observed in later *** activity of acid-phosphatase at the moderate temperature(10–20℃)was visibly higher than that at the high temperature(20–30℃)and CWs with Ag NPs addition had no appreciable differences compared with the ***-throughput sequencing results indicated that the microbial richness,diversity and composition of CWs were distinctly affected with the extension of exposure time at different Ag NPs ***,the phosphorus removal performance of CWs did not decline with the decrease of polyphosphate accumulating organisms(PAOs),which also confirmed that adsorption precipitation was the main way of phosphorus removal in *** study suggested that Ag NPs and phosphorus could be removed synergistically in the coexistence *** work has some reference for evaluating the influences of Ag NPs on the phosphorus removal and the interrelation between them in CWs.

关键词： Silver nanoparticles(AgNPs) Phosphorus removal Constructed wetlands Enzymatic activity Microbial community

Deflection of cavitation bubble near the rigid wall with a gas-containing hole

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Journal of Hydrodynamics 2023年第2期35卷 330-337页

作者： Yu-rong Sun Qiang Zhong Zhi-feng Yao Dan Zi Ruo-fu Xiao Fu-jun Wang College of water Resources and Civil Engineering China Agricultural UniversityBeijing100083China Beijing Engineering Research center of Safety and Energy Saving Technology for water supply Network System Beijing100083China

The presence of a rigid wall causes a microjet of the cavitation bubble to collapse to move toward the wall,while a free surface does the *** a rigid wall surface is combined with a free surface,it may affect the direction of the *** motive of this study is to find out the influence of the dynamic behavior of a laser-induced bubble near the rigid wall with a gas-containing *** of the bubble at different distances from the gas-containing hole in the horizontal and vertical directions were recorded by a high-speed camera(2.3×10^(5) fps).When the bubble collapse near the boundary,the bubble will produce two situations:away from or toward the *** focuses on the direction of the bubble,the oscillation period of a bubble,and reflection angle,and quantitative analysis of the *** was found that the boundary not only changes the morphologic of the bubble and the overall direction of movement but also affects the oscillation *** addition,it can control the deflection of the bubble.

关键词： Cavitation bubble bubble migration deflection angle gas-containing hole

A novel Omega-driven dynamic PANS model

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Journal of Hydrodynamics 2020年第4期32卷 710-716页

作者： Chao-yue Wang Fu-jun Wang Ben-hong Wang Yuan Tang Hao-ru Zhao College of water Resources and Civil Engineering China Agricultural UniversityBeijing 100083China Beijing Engineering Research center of Safety and Energy Saving Technology for water supply Network System Beijing 100083China

A novel Omega(Ω)-driven dynamic partially-averaged Navier-Stokes(PANS)model is proposed in this *** ratio of the modeled-to-total turbulent kinetic energies fk is dynamically adjusted by the rigid vorticity ratio(the ratio of the rigid vorticity to the total vorticity),the key parameter of the Ω vortex identification *** classical flow cases with rotation and curvature are used to test the *** results show that the turbulent viscosity is effectively adjusted by the new dynamic fk and the LES-like mode is activated,which can help the revelation of more turbulence information and improve the prediction *** new PANS model does not contain any explicit dependency on the grid size and enjoys good adaptability to the flow fields,and can be used for efficient engineering computations of the turbulent flows in the hydraulic machinery.

关键词： Dynamic partially-averaged Navier-Stokes(PANS) turbulence model Omega engineering computations

Identification of causative compounds and microorganisms for musty odor occurrence in the Huangpu River,China

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Journal of Environmental Sciences 2013年第3期25卷 460-465页

作者： Daolin Sun Jianwei Yu Wei An Min Yang Guoguang Chen Shujun Zhang Research center for Eco-Environmental Sciences Chinese Academy of Sciences Shanghai Municipal Control and Monitor Centre of water supply The Administrative center for China's Agenda 21 Ministry of Science and Technology

There are regular problems of musty odor in the Huangpu River,a major source of drinking water for Shanghai,*** this study,the musty odor and its main causative compounds in the Huangpu River source water were confirmed through a yearly investigation using flavor profile analysis combined with HSPME-GC-MS *** investigation showed that 2-methylisoborneol （2-MIB） with a concentration level between 28.6 and 71.0 ng/L was responsible for the musty odor in summer from July to *** observation confirmed with the cloning results showed that Phormidium spp.,which accounted for 80%-95% of the algal cell density,was the microorganisms responsible for the production of 2-MIB and the estimated 2-MIB yield was 0.022 pg/*** from a wide-area sampling campaign in the Huangpu River watershed showed that,other than the large tributaries receiving water from Tai Lake,several small creeks close to the intake may have contributed most of the 2-MIB and the Phormidium *** the Huangpu River source *** study provides methodology for the investigation of odor causing compounds and microorganisms in river-type source water,and the result will be useful for water quality control in both source water and drinking water.

关键词： river water source 2-methylisoborneol musty odor Phormidium watershed

Analytical approach for sheet flow transport in purely acceleration-skewed oscillatory flow

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International Journal of Sediment Research 2018年第3期33卷 234-242页

作者： Xin Chen Fujun Wang Xuelin Tang Beijing Engineering Research center of Safety and Energy Saving Technology for water supply Network System China Agricultural University

An instantaneous analytical approach is developed to predict sheet flow transport in purely accelerationskewed oscillatory flow. The approach is derived from exponential approximations of velocity and concentration profiles above a mobile seabed, and it particularly considers factors of phase lead; phase lag(i.e. phase residual and phase shift); acceleration modification; and asymmetries in shear stress,roughness height, and boundary layer development. The approach can predict net boundary layer flow above a mobile seabed, and can revert to the classical bedload model. Instantaneous and net sediment transport rates are studied using the approach. The instantaneous sediment transport rate in an onshore flow stage can be approximated by a power function of velocity in which the exponent is confirmed to range between 1 and 5 with a decrease in the phase residual. The net sediment transport rate predicted using the approach is validated using a considerable amount of measured data, and compared with existing instantaneous and half-period type models that consider the phase lag or acceleration modification. For the net sediment transport rate in purely acceleration-skewed oscillatory flow, the phase residual is less important than the acceleration-skewed boundary layer difference between onshore and offshore acceleration stages.

关键词： Analytical approach Sheet flow Acceleration-skewed oscillatory flow Phase lag Boundary layer flow