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1.
Inorg Chem ; 63(20): 9212-9220, 2024 May 20.
Article in English | MEDLINE | ID: mdl-38718298

ABSTRACT

The Electrochemical reduction of nitrate to ammonia (NH3) is a process of great significance to energy utilization and environmental protection. However, it suffers from sluggish multielectron/proton-involved steps involving coupling reactions between different reaction intermediates and active hydrogen species (Hads) produced by water decomposition. In this study, a Ru-doped NiFe-MIL-53 (NiFeRu-MIL-53) supported on Ni foam (NF) has been designed for the nitrate reduction reaction (NO3RR). The NiFeRu-MIL-53 exhibits excellent NO3RR activity with a maximum Faradaic efficiency (FE) of 100% at -0.4 V vs. RHE for NH3 and a maximum NH3 yield of 62.39 mg h-1 cm-2 at -0.7 V vs. RHE in alkaline media. This excellent performance for the NO3RR is attributed to a strong synergistic effect between Ru and reconstructed NiFe(OH)2. Additionally, the doped Ru facilitates water dissociation, leading to an appropriate supply of Hads required for N species hydrogenation during NO3RR, thereby further enhancing its performance. Furthermore, in situ Raman analysis reveals that incorporating Ru facilitates the reconstruction of MOFs and promotes the formation of hydroxide active species during the NO3RR process. This work provides a valuable strategy for designing electrocatalysts to improve the efficiency of the reduction of electrochemical nitrate to ammonia.

2.
ACS Omega ; 9(19): 21459-21466, 2024 May 14.
Article in English | MEDLINE | ID: mdl-38764652

ABSTRACT

Medicated bath is the most common spiking method used in the development of matrix reference materials for aquatic products; however, the environmental issues caused by the treatment of waste liquid after medicated bath cannot be ignored. We proposed an environmentally friendly spiking method based on microfluidics, which significantly improved the drug utilization rate without the need for subsequent drug residue treatment. Finely processed minced fish samples were fully mixed with quinolone drugs, and minced fish gel microspheres were prepared by microfluidic technology, utilizing the gel's water-locking function to enhance the drug-loading capacity. The results showed that this method can significantly increase the drug-loading capacity of the matrix (2.33-4.03 times) compared with the traditional spiking methods. In addition, the matrix reference material prepared by this method has good stability, and the drug concentration was adjustable and controllable.

3.
Int J Biol Macromol ; 267(Pt 2): 131188, 2024 May.
Article in English | MEDLINE | ID: mdl-38599434

ABSTRACT

Traditional spiking methods for preparing matrix reference material of aquatic products is difficult to control the drug content in the matrix, especially one matrix containing multiple drugs. Minced fish is commonly used for the preparation of matrix reference materials in aquatic products, which is a relatively complex matrix with stickiness and difficult handling. Drug loading capacity is a key factor affecting the effectiveness of matrix reference materials. Here, we proposed a new spiking approach to improve the drug loading capacity of seven quinolones based on microfluidics, simultaneously. Fresh grass carp tissue underwent grinding, fine filtration, centrifugation and reconstituted in distilled water to form a liquid sample, which was subsequently mixed with a sodium alginate solution (1 %) at a ratio of 1:1.2. The mixed solution was supplemented with seven quinolones of equal concentration, followed by the preparation of uniform fish gel microspheres using microfluidic technology. The results indicated that the recoveries of seven quinolones ranged from 82.54 % to 114.17 %, demonstrating a significant improvement in the drug loading capacity of these quinolones compared to traditional methods. Moreover, the drug concentration in the matrix can be precisely controlled. A strong linear relationship was observed between the concentration of seven quinolones in the matrix and its initial concentration, which could serve as a reference for the development of other matrix reference materials.


Subject(s)
Microfluidics , Quinolones , Animals , Quinolones/chemistry , Microfluidics/methods , Carps , Alginates/chemistry , Fishes , Microspheres
4.
Inorg Chem ; 63(8): 3955-3961, 2024 Feb 26.
Article in English | MEDLINE | ID: mdl-38334267

ABSTRACT

Electrocatalytic nitrate reduction reaction offers a sustainable approach to treating wastewater and synthesizing high-value ammonia under ambient conditions. However, electrocatalysts with low faradaic efficiency and selectivity severely hinder the development of nitrate-to-ammonia conversion. Herein, Ru-doped ultrasmall copper nanoparticles loaded on a carbon substrate (Cu-Ru@C) were fabricated by the pyrolysis of Cu-BTC metal-organic frameworks (MOFs). The Cu-Ru@C-0.5 catalyst exhibits a high faradaic efficiency (FE) of 90.4% at -0.6 V (vs RHE) and an ammonia yield rate of 1700.36 µg h-1mgcat.-1 at -0.9 V (vs RHE). Moreover, the nitrate conversion rate is almost 100% over varied pHs (including acid, neutral, and alkaline electrolytes) and different nitrate concentrations. The remarkable performance is attributed to the synergistic effect between Cu and Ru and the excellent conductivity of the carbon substrate. This work will open an exciting avenue to exploring MOF derivatives for ambient ammonia synthesis via selective electrocatalytic nitrate reduction.

5.
J Environ Sci (China) ; 139: 245-257, 2024 May.
Article in English | MEDLINE | ID: mdl-38105052

ABSTRACT

Water fluoride pollution has caused non-negligible harm to the environment and humans, and thus it is crucial to find a suitable treatment technology. In this study, La-Fe@PTA adsorbent was synthesized for the defluoridation of mine water. The results showed that the optimum conditions for defluoridation by La-Fe@PTA were pH close to 7.0, the initial F- concentration of 10 mg/L, the dosage of 0.5 g/L and the adsorption time of 240 min. Compared with SO42‒, Cl‒, NO3‒, Ca2+ and Mg2+, CO32‒ and HCO3‒ presented severer inhibition on fluoride uptake by La-Fe@PTA. The adsorption process fits well with the pseudo-second-order kinetic model and Freundlich model, and the maximum adsorption capacity of Langmuir model was 95 mg/g. Fixed-bed adsorption results indicated that fluoride in practical fluorinated mine water could be effectively removed from 3.6 mg/L to less than 1.5 mg/L within 130 bed volume (BV) by using 1.5 g La-Fe@PTA. Furthermore, the adsorbent still had good adsorption capacity after regeneration, which confirms the great application potential of La-Fe@PTA as a fluoride ion adsorbent. The mechanism analysis showed that La-Fe@PTA adsorption of fluorine ions is a physicochemical reaction driven by electrostatic attraction and ion exchange.


Subject(s)
Metal-Organic Frameworks , Water Pollutants, Chemical , Water Purification , Humans , Fluorides , Water , Adsorption , Kinetics , Hydrogen-Ion Concentration , Water Purification/methods
6.
Water Res ; 245: 120600, 2023 Oct 15.
Article in English | MEDLINE | ID: mdl-37713791

ABSTRACT

This study investigated the formation of dichloroacetamide (DCAM) and dichloroacetic acid (DCAA) from the abatement of three phenicol antibiotics (PABs, chloramphenicol, thiamphenicol, and florfenicol) during ozonation and post-chlor(am)ination. Results show that the three PABs have a low ozone reactivity (kO3 = 0.11‒0.12 M-1 s-1), and therefore are mainly abated through the hydrogen abstraction mechanism by hydroxyl radicals (•OH) during ozonation. During PAB degradation, the carboxamide moiety in the parent molecules can be cleaved off by •OH attack and thus gives rise to DCAM. The formed DCAM can then be further oxidized by O3 and/or •OH to DCAA as a more stable transformation product (TP). When the three PABs were adequately abated (abatement efficiency of ∼82 %‒95 %), the molar yields of DCAM and DCAA were determined to be 2.79 %‒4.71 % and 32.9 %‒37.2 %, respectively. Furthermore, post-chloramination of the ozonation effluents increased the yields of DCAM and DCAA slightly to 4.20 %‒6.45 % and 39.0 %‒41.1 %, respectively. In comparison, post-chlorination eliminated DCAM in the solutions, but significantly increased DCAA yields to ∼100 % due to the further conversion of DCAM and other ozonation TPs to DCAA by chlorine oxidation. The results of this study indicate that high yields of DCAM and DCAA can be generated from PAB degradation during ozonation, and post-chlorination and post-chloramination will result in very different fates of DCAM and DCAA in the disinfected effluent. The formation and transformation of DCAM and DCAA during PAB degradation need to be taken into account when selecting multi-barrier treatment processes for the treatment of PAB-containing water.


Subject(s)
Ozone , Water Pollutants, Chemical , Water Purification , Anti-Bacterial Agents , Dichloroacetic Acid , Water Pollutants, Chemical/analysis , Halogenation , Water Purification/methods , Disinfection/methods
7.
Water Res ; 244: 120480, 2023 Oct 01.
Article in English | MEDLINE | ID: mdl-37598568

ABSTRACT

Singlet oxygen (1O2) has often been identified by the popularly used quenching method as a more important reactive species (RS) than sulfate radicals (SO4•-) and hydroxyl radicals (•OH) for pollutant abatement during persulfate-based advanced oxidation processes (PS-AOPs), especially those activated by carbon-based catalysts. However, latest studies have demonstrated that the quenching method actually can often mislead the interpretations of the role of RS for pollutant abatement during AOPs due to various confounding effects caused by adding high-concentration quenchers in the system. To clarify the role of 1O2 in PS-AOPs, this study developed a probe compound-based experimental and kinetic model to quantify the concentrations and exposures of 1O2, SO4•-, and •OH, as well as their relative contributions to pollutant abatement during a cobalt oxide incorporated carbon nanotubes activated peroxymonosulfate (Co3O4@CNTs/PMS) process. Results show that during the Co3O4@CNTs/PMS process, the exposures and transient concentrations of 1O2 were about 19.6 and 41.3 times higher than those of SO4•- and •OH, respectively. However, the relative contribution of 1O2 to the abatement of most pollutants tested in this study (e.g., sulfisoxazole, sulfamethoxyprazine, trimethoprim, and metoprolol) is generally negligible (f1O2 ≤ 8%) compared to that of SO4•- and •OH ( [Formula: see text]  = 15%-98% and f•OH = 2%-78%) because of the significantly lower reactivity of 1O2 with these compounds than that of SO4•- and •OH. Reasons for misidentifying 1O2 as the dominant RS for pollutant abatement by the quenching method were then analyzed based on reaction kinetics principles. The results of this study highlight that while 1O2 can be generated in significant amounts and be present at higher concentrations than SO4•- and •OH in PS-AOP systems, 1O2 is unlikely to be the dominant RS for the abatement of most pollutants during the PS-AOPs because of its weak and selective oxidation capacity, and caution should be taken when using the quenching method to evaluate the role of RS for pollutant abatement by the PS-AOPs.


Subject(s)
Environmental Pollutants , Nanotubes, Carbon , Water Pollutants, Chemical , Singlet Oxygen , Water Pollutants, Chemical/analysis , Peroxides , Oxidation-Reduction
8.
Front Psychol ; 14: 1197170, 2023.
Article in English | MEDLINE | ID: mdl-37359871

ABSTRACT

The present study aims to investigate the associations among math self-efficacy, parenting style, and math anxiety in primary school children. The sample comprised 400 participants, aged between 10 and 11 years old, from an elementary school in China. Participants completed three self-reported questionnaires on math anxiety, parenting styles and math self-efficacy. The results revealed that rejection was strongly and positively correlated with math anxiety, while emotional warmth was negatively related to math anxiety. Interestingly, math anxiety was found to be related to rejection, with math self-efficacy playing a mediating role in this relationship. Conversely, math self-efficacy played a mediating role in the relationship between parenting styles and math anxiety, while over protection exhibited no significant correlation with math anxiety. The study also showed that gender differences existed in the level of math anxiety and math self-efficacy, with boys exhibiting lower math anxiety and higher math self-efficacy than girls. These results provide important insights into the development and treatment of math anxiety in primary school children. Specifically, parents and educators should focus on enhancing children's math self-efficacy beliefs, while adopting a parenting style characterized by emotional warmth and low levels of rejection.

9.
Environ Res ; 210: 112986, 2022 07.
Article in English | MEDLINE | ID: mdl-35192806

ABSTRACT

Although there are some review papers on carbon capture, utilization and storage (CCUS), hardly any of these reviews are focused on the role of CO2 enhanced oil recovery (EOR) in accelerating carbon neutrality in China. In this review, strategies to achieve carbon neutrality is briefly but critically discussed, followed by a review of CO2-EOR as a promising technology. Especially, data analysis, including the number of publications on China's carbon neutrality, per capita CO2 emissions, China's power generation, and the crude oil production of China's large oilfields, is carried out to make the discussion more comprehensive. Given the large amount of coal consumed in China, the high percent of electricity generated with coal, and the slow penetration of renewables already observed, it seems unlikely that 2060 targets will be met without CCUS. In order to achieve carbon neutrality, both reduction in carbon emissions and increase in carbon sequestration are inevitable. Furthermore, it is concluded that CO2 storage through EOR is likely to have a bright future. However, there are some critical issues to be solved, including the technical issues, leakage and safety issues, cost issues, policy issues, etc. In order to turn CO2-EOR into a reliable and more favorable technology, more research and efforts are needed to solve these issues, including advancing carbon capture technologies, improving storage technologies, developing effective monitoring technologies, deploying government support and incentive policies, etc.


Subject(s)
Carbon Dioxide , Carbon , Carbon/analysis , Carbon Dioxide/analysis , Carbon Sequestration , China , Coal/analysis , Technology
10.
Chemosphere ; 287(Pt 2): 132131, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34492413

ABSTRACT

Ion exchange membranes (IEMs) are widely used in water treatment applications such as electrodialysis. However, the exploration of IEMs as effective antibacterial food contact materials (e.g., food packaging membranes) against pathogenic bacteria to ensure food safety has not been reported. Here, we report a simple but effective method to prepare high performance antibacterial membranes via ion exchange coupled with in-situ reduction. The general membrane properties are characterized using SEM, EDS, FTIR, XPS, XRD, DSC, TGA, water uptake, etc. The distribution of silver and copper in the membranes are generally in line with the distribution of sulfur, indicating that the antibacterial ions are introduced into the membranes via ion exchange and are bonded with the sulfonate groups in the membranes. The antibacterial performance is investigated using zone of inhibition tests and continuous bacteria growth inhibition tests. All of the prepared membranes show obvious antibacterial activities compared to the bare cation exchange membranes. The diameters of inhibition zone against Staphylococcus aureus (S. aureus) are all larger than those of Escherichia coli (E. coli), indicating that the prepared membranes are more efficient in inhibiting S. aureus compared to E. coli. Furthermore, the silver-based membrane shows more sustainable antibacterial activities compared to the copper-based membrane. Especially, the results clearly reveal that the silver-based membrane is capable of killing bacteria instead of just inhibiting the growth of bacteria. We have shown for the first time that membranes derived from IEMs have the potential as food contact materials to inhibit the growth of pathogenic bacteria so as to eliminate the risk of bacterial infections and meanwhile delay food spoilage due to bacteria growth.


Subject(s)
Metal Nanoparticles , Silver , Anti-Bacterial Agents/pharmacology , Copper , Escherichia coli , Ion Exchange , Microbial Sensitivity Tests , Silver/pharmacology , Staphylococcus aureus
11.
Environ Sci Pollut Res Int ; 28(39): 54511-54530, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34431060

ABSTRACT

Environment protection and food safety are two critical issues in the world. In this review, a novel approach which integrates statistical study and subjective discussion was adopted to review recent advances on environment and food safety. Firstly, a scientometric-based statistical study was conducted based on 4904 publications collected from the Web of Science Core Collection database. It was found that the research on environment and food safety was growing steadily from 2001 to 2020. Interestingly, the statistical analysis of most-cited papers, titles, abstracts, keywords, and research areas revealed that the research on environment and food safety was diverse and multidisciplinary. In addition to the scientometric study, strategies to protect environment and ensure food safety were critically discussed, followed by a discussion on the emerging research topics, including emerging contaminates (e.g., microplastics), rapid detection of contaminants (e.g., biosensors), and environment friendly food packaging materials (e.g., biodegradable polymers). Finally, current challenges and future research directions were proposed.


Subject(s)
Environmental Pollution , Food Safety , Plastics , Environmental Monitoring
12.
J Neurosci Methods ; 362: 109320, 2021 10 01.
Article in English | MEDLINE | ID: mdl-34390757

ABSTRACT

BACKGROUND: Emotions play a crucial role in human communication and affect all aspects of human life. However, to date, there have been few studies conducted on how movements under different emotions influence human brain activity and cortico-muscular coupling (CMC). NEW METHODS: In this study, for the first time, electroencephalogram (EEG) and electromyogram physiological electrical signals were used to explore this relationship. We performed frequency domain and nonlinear dynamics analyses on EEG signals and used transfer entropy to explore the CMC associated with the emotion-movement relationship. To study the transmission of information between different brain regions, we also constructed a functional brain network and calculated various network metrics using graph theory. RESULTS: We found that, compared with a neutral emotional state, movements made during happy and sad emotions had increased CMC strength and EEG power and complexity. The functional brain network metrics of these three emotional states were also different. COMPARISON WITH EXISTING METHODS: Much of the emotion-movement relationship research has been based on subjective expression and external performance. Our research method, however, focused on the processing of physiological electrical signals, which contain a wealth of information and can objectively reveal the inner mechanisms of the emotion-movement relationship. CONCLUSIONS: Different emotional states can have a significant influence on human movement. This study presents a detailed introduction to brain activity and CMC.


Subject(s)
Brain , Electroencephalography , Electromyography , Emotions , Humans , Movement
13.
Neurosci Lett ; 760: 136012, 2021 08 24.
Article in English | MEDLINE | ID: mdl-34098023

ABSTRACT

The study of functional corticomuscular coupling can reflect the interaction between the cerebral cortex and muscle tissue, thereby helping to understand how the brain controls muscle tissue and the effect of muscle movement on brain function. This study proposes a detection model of the coupling strength between the cortex and muscles. The detection model uses an adaptive selector to choose the optimal long short-term memory network, uses this network to extract the features of electroencephalography and electromyography, and finally transforms time characteristics into the frequency domain. The transfer entropy is used to represent the interaction intensity of signals in different frequency bands. Using this model, we analyze the coupling relationship between the cortex and muscles in the three movements of wrist flexion, wrist extension, and clench fist, and compare the model with traditional wavelet coherence analysis and deep canonical correlation analysis. The experimental results show that our model can not only express the bidirectional coupling relationship between different frequency bands but also suppress the possible false coupling that traditional methods may detect. Our research shows that the proposed model has great potential in medical rehabilitation, movement decoding, and other fields.


Subject(s)
Memory, Long-Term/physiology , Memory, Short-Term/physiology , Motor Cortex/physiology , Movement/physiology , Muscle, Skeletal/physiology , Canonical Correlation Analysis , Electroencephalography , Electromyography , Entropy , Female , Healthy Volunteers , Humans , Male , Models, Neurological , Movement Disorders/physiopathology , Movement Disorders/rehabilitation
14.
Chemosphere ; 282: 130817, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34091294

ABSTRACT

Ion exchange membranes (IEMs) are undergoing prosperous development in recent years. More than 30,000 papers which are indexed by Science Citation Index Expanded (SCIE) have been published on IEMs during the past twenty years (2001-2020). Especially, more than 3000 papers are published in the year of 2020, revealing researchers' great interest in this area. This paper firstly reviews the different types (e.g., cation exchange membrane, anion exchange membrane, proton exchange membrane, bipolar membrane) and electrochemical properties (e.g., permselectivity, electrical resistance/ionic conductivity) of IEMs and the corresponding working principles, followed by membrane synthesis methods, including the common solution casting method. Especially, as a promising future direction, green synthesis is critically discussed. IEMs are extensively applied in various applications, which can be generalized into two big categories, where the water-based category mainly includes electrodialysis, diffusion dialysis and membrane capacitive deionization, while the energy-based category mainly includes reverse electrodialysis, fuel cells, redox flow battery and electrolysis for hydrogen production. These applications are comprehensively discussed in this paper. This review may open new possibilities for the future development of IEMs.


Subject(s)
Membranes, Artificial , Renal Dialysis , Cations , Ion Exchange , Water
15.
Chemosphere ; 279: 130605, 2021 Sep.
Article in English | MEDLINE | ID: mdl-33894512

ABSTRACT

Rapid and highly efficient treatment of acid mine drainage (AMD) is still challenging due to the low pH and high metal concentrations in it. This research focuses on a novel treatment method of AMD using direct contact membrane distillation (DCMD) and photocatalysis to recover water and utilize iron. In the DCMD process without pretreatment, the flux decreased by 93.38%. If pretreated by adding sodium oxalate, scale formation potential was effectively mitigated due to the removal of calcium and complexing of iron. For the treatment of the pretreated AMD (PAMD), 60% of water was recovered in the DCMD process with the flux decrease of 22%. The concentrate obtained from the DCMD process demonstrated high photocatalytic activity in the methylene blue (MB) degradation in an aqueous solution. In addition, the Fe (III)-oxalate complexes in the concentrate were reduced to insoluble Fe (II)-oxalate with visible light irradiation, which could be separated by sedimentation and used as a Fenton catalyst. Hence, this novel method exhibits great advantages on effectively inhibiting DCMD membrane fouling during AMD treatment, producing high-quality distillate with low conductivity, and realizing near zero-discharge of AMD.


Subject(s)
Water Pollutants, Chemical , Water Purification , Distillation , Iron , Membranes, Artificial , Mining , Water , Water Pollutants, Chemical/analysis
16.
Chemosphere ; 266: 129230, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33316471

ABSTRACT

The electro-peroxone (EP) process has been considered an attractive alternative to conventional ozonation for micropollutant abatement in water treatment. However, how to integrate the EP process into the water treatment trains in water utilities has yet to be investigated. This study compared micropollutant abatement during the EP treatment of potable source water with and without pretreatment of biological oxidation, flocculation, sedimentation, and filtration. Results show that this pretreatment train removed 39% of dissolved organic carbon (DOC) and 28% of the UV254 absorbance of the raw water, leading to higher ozone (O3) stability in the treated water. By electrochemically generating hydrogen peroxide to accelerate O3 decomposition to hydroxyl radicals (•OH), the EP process considerably shortened the time required for ozone depletion and micropollutant abatement during the treatment of both the raw and pretreated water to ∼1 min, compared to ∼3 and 7.5 min during conventional ozonation of the raw and treated water, respectively. For the same specific ozone dose of 1 mg O3 mg-1 DOC (corresponding to 4.3 and 2.8 mg O3 L-1 for the raw and treated water, respectively), the abatement efficiencies of micropollutants with moderate and low ozone reactivity were increased by ∼10-15%, while the energy consumption for micropollutant abatement was decreased by ∼24-56% during the EP treatment of the treated water than the raw water. These results indicate that partial removal of DOC and ammonia from the raw water by the pretreatment train has a beneficial effect on enhancing micropollutant abatement and reducing energy consumption of the EP process. Therefore, it is more cost-effective to integrate the EP process after the pretreatment train in water utilities for micropollutant abatement.


Subject(s)
Ozone , Water Pollutants, Chemical , Water Purification , Hydrogen Peroxide , Oxidation-Reduction , Wastewater , Water Pollutants, Chemical/analysis
17.
Brain Res ; 1752: 147221, 2021 02 01.
Article in English | MEDLINE | ID: mdl-33358729

ABSTRACT

Electroencephalogram (EEG) and electromyogram (EMG) signals during motion control reflect the interaction between the cortex and muscle. Therefore, dynamic information regarding the cortical-muscle system is of significance for the evaluation of muscle fatigue. We treated the cortex and muscle as a whole system and then applied graph theory and symbolic transfer entropy to establish an effective cortical-muscle network in the beta band (12-30 Hz) and the gamma band (30-45 Hz). Ten healthy volunteers were recruited to participate in the isometric contraction at the level of 30% maximal voluntary contraction. Pre- and post-fatigue EEG and EMG data were recorded. According to the Borg scale, only data with an index greater than 14<19 were selected as fatigue data. The results show that after muscle fatigue: (1) the decrease in the force-generating capacity leads to an increase in STE of the cortical-muscle system; (2) increases of dynamic forces in fatigue leads to a shift from the beta band to gamma band in the activity of the cortical-muscle network; (3) the areas of the frontal and parietal lobes involved in muscle activation within the ipsilateral hemibrain have a compensatory role. Classification based on support vector machine algorithm showed that the accuracy is improved compared to the brain network. These results illustrate the regulation mechanism of the cortical-muscle system during the development of muscle fatigue, and reveal the great potential of the cortical-muscle network in analyzing motor tasks.


Subject(s)
Cerebral Cortex/physiology , Muscle Fatigue/physiology , Muscle, Skeletal/physiology , Adult , Beta Rhythm , Electroencephalography , Electromyography , Female , Gamma Rhythm , Humans , Isometric Contraction , Male , Neural Pathways/physiology , Signal Processing, Computer-Assisted , Young Adult
18.
Water Res ; 183: 116115, 2020 Sep 15.
Article in English | MEDLINE | ID: mdl-32652347

ABSTRACT

The ultraviolet/chlorine (UV/Cl2) process is an emerging advanced oxidation technology for micropollutant abatement in water and wastewater treatment. However, the application of the conventional UV/Cl2 process in decentralized systems is limited by the transport and management of liquid chlorine. To overcome this limitation, this study evaluated an electrochemically driven UV/Cl2 (E-UV/Cl2) process for micropollutant abatement under conditions simulating decentralized water treatment. The E-UV/Cl2 process combines UV irradiation with in situ electrochemical Cl2 production from anodic oxidation of chloride (Cl-) in source waters. The results show that with typical Cl- concentrations present in water sources for decentralized systems (30-300 mg/L Cl-), sufficient amounts of chlorine could be quickly electrochemically produced at the anode to enable E-UV/Cl2 process for water treatment. Due to its multiple mechanisms for micropollutant abatement (direct photolysis, direct electrolysis, Cl2-mediated oxidation, as well as hydroxyl radical and reactive chlorine species oxidation), the E-UV/Cl2 process effectively eliminated all micropollutants (trimethoprim, ciprofloxacin, metoprolol, and carbamazepine) spiked in a surface water in 5 min. In contrast, at least one micropollutant with ∼20-80% residual concentrations could still be detected in the water treated by 10 min of UV irradiation, chlorination, electrolysis, and the conventional UV/Cl2 process under similar experimental conditions. The electrical energy per order (EEO) for micropollutant abatement ranged from 0.15 to 1.8 kWh/m3 for the E-UV/Cl2 process, which is generally comparable to that for the conventional UV/Cl2 process (0.14-2.7 kWh/m3). These results suggest that by in-situ generating Cl2 from anodic oxidation of Cl-, the E-UV/Cl2 process can overcome the barrier of the conventional UV/Cl2 process and thus provide a promising technology for micropollutant abatement in decentralized water treatment systems.


Subject(s)
Water Pollutants, Chemical , Water Purification , Chlorine , Oxidation-Reduction , Ultraviolet Rays , Wastewater/analysis
19.
J Hazard Mater ; 390: 122180, 2020 05 15.
Article in English | MEDLINE | ID: mdl-32006850

ABSTRACT

In this study, the abatement of neonicotinoid insecticide, thiamethoxam, by single ozonation, ozone/ultraviolet (O3/UV) and electro-peroxone (EP) process was evaluated. The second-order rate constants for the reaction of thiamethoxam with O3 and hydroxyl radical (OH) at pH 7 were determined to be 15.4 M-1 s-1 and 3.9 × 109 M-1 s-1, respectively. The degradation pathways of thiamethoxam were proposed based on quantum chemical calculations and transformation products were identified using chromatographic and mass-spectrometric techniques. The acute and chronic toxicity of thiamethoxam and its major TPs to various aquatic organisms were assessed. With typical ozone doses applied in water treatment (≤5 mg/L), thiamethoxam was abated by only ∼16-32 % in two real water matrices (groundwater and surface water) during single ozonation, but by ∼100 % and >70 % during the O3/UV and EP treatment, respectively. The energy demand to abate 90 % thiamethoxam in the two water matrices was generally comparable for single ozonation and the EP process (∼0.14 ±â€¯0.03 kW h/m3), but higher for the O3/UV process (0.21-0.22 kW h/m3). These results suggest that single ozonation is unable to sufficiently abate thiamethoxam under typical conditions of water treatment. Therefore, ozone-based advanced oxidation processes are needed to enhance thiamethoxam abatement.

20.
ISA Trans ; 104: 122-129, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31759683

ABSTRACT

The consensus problem via event-triggered strategy of nonlinear multi-agent systems (MASs) with Markovian switching topologies is addressed in this paper. To simplify information transmission, a distributed event-triggered mechanism (ETM) is designed. By combining the Markovian switching topologies and ETM, an appropriate consensus control protocol is presented. Considering the impact of delay on systems stability, the system model is transformed by the delay system approach. By choosing a Lyapunov-Krasovskii function and applying linear matrix inequalities technique, sufficient conditions are obtained to ensure the consensus stability with H∞ norm bound of the MASs. A numerical simulation is given to confirm the effectiveness of the designed method.

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