摘要：
A novelty in-situ heterogeneous electro-Fenton based on boron-modified and co-modified carbon felts (CF) such as B-CF, B, Fe-CF and B, Co-CF was employed for phosphorus nutrients treatment in dredged sediment. During which B, Fe-CF (1:1) was the optimal cathode for phosphorus nutrients and organic matter treatment with organic phosphorus (OP) and non-apatite inorganic phosphorus (Fe-P) conversion rates of 26.84% and 63.21%, respectively, since the generated H2O2 on bifunctional cathode could produce center dot OH with material surface reduced Fe(II). Characterized by SEM, XRD and XPS, B and Fe were successfully loaded on the electrode with elemental percentages of 0.99% and 4.40%, while B2O3 and Fe2O3 were detected. The operating parameters like initial pH and current density were explored. B, Fe-CF had a high stability and outstanding catalytic capacity for 5 cycles of phosphorus nutrient treatment. The possible mechanism was also proposed based on the electron paramagnetic resonance (EPR) and radical quenching experiment, which demonstrated that center dot OH and SO4 center dot- mainly contributed to phosphorus nutrients treatment. In this work, a highly efficient and stable carbon material was successfully prepared to treat refractory pollutants in dredging sediment, which provides new ideas and methods for subsequent resource utilization.
摘要：
Metal sulfides have gained significant attention as cocatalysts for Fenton/Fenton-like processes in recent years due to their ability to reduce trivalent iron (Fe3+). Nevertheless, the issue of hydrogen sulfide (H2S) formation as a secondary contaminant is a significant concern. In this work, tungsten carbide (WC) was innovatively intro-duced into the Fenton-like process based on ferrous ion/peroxymonosulfate (Fe2+/PMS). The results showed that the WC/Fe2+/PMS system had a significantly higher degradation efficiency and rate for tetracycline hydro-chloride (TC) than the Fe2+/PMS system. The WC/Fe2+/PMS system can work efficiently over a wide pH range (2.8-8.5), and WC has excellent reusability with negligible metal leaching. X-ray photoelectron spectrum analysis proved that the presence of W(IV) on the WC surface contributes to its excellent co-catalytic performance. Electrochemical characterization indicated that WC can facilitate the electron transfer of the system. Electron Paramagnetic Resonance analysis demonstrated that WC significantly improves the generation of four oxidative species by the Fe2+/PMS system as a result of the enhanced PMS activation due to the continuous reduction of Fe(III) by WC. Moreover, the WC/Fe2+/PMS system can work effectively under a complex water matrix and has an excellent degradation effect on other pollutants. In summary, this study provides a novel and eco-friendly cocatalyst to accelerate the Fe3+/Fe2+ cycle and activate PMS for TC degradation.
摘要：
The hydrogen addition to liquid methane gas (LMG) engines based on the rational control strategy is considered to be a promising approach to improve the performance of LMG engines. However, the current studies are limited to a few operating points. To comprehensively develop a control strategy of hydrogen addition for high compression ratio LMG engines, the effects of hydrogen addition on the emissions, combustion, and performance of an LMG engine are experimentally investigated under all operating conditions in this study. Furthermore, to achieve the optimal performance of the hydrogen-LMG engine with the optimal hydrogen blending, the coupled simulation model of MATLAB/Simulink and GT-Power is established based on the test bench, and the multiple operating parameters of the calibrated numerical model are optimized by using genetic algorithm. The results show that the maximum increases in the brake thermal efficiency with increasing hydrogen energy share (HES) are 1.6, 0.9 and 0.6 percentage points under low, medium and high loads, respectively. Correspondingly, the maximum reduction in EBSFC under low, medium and high loads is 6.5 %, 2.2 % and 1.4 %, respectively. The ignition delay is reduced and the combustion is promoted with the increase in HES. As a result, the cylinder pressure and HRR rise faster and reach a higher peak earlier. In addition, the 50 % combustion location is advanced and the 10-90 % combustion duration is shortened. In terms of emissions, the increasing HES promotes the NOx emissions and reduces the HC emissions. Especially at medium and high loads, the NOx emissions rise sharply with increasing HES. It is desirable that HES should not exceed 15 %, 4 % and 2 % at low, medium and high loads, respectively. In addition, by co-optimizing the intake valve opening timing, exhaust valve opening timing and the spark angle, the BSFC of the hydrogen-LMG engine with the optimal HES under 1200 rpm and BMEP of 6 bar is still improved by 2.2 %. This study provides new insights to further explore the energy-saving potential of hydrogen-LMG engines.
作者机构：
[Zhou, Feng; Zhou, F; Yu, Juan; Zeng, Wen] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Peoples R China.;[Fu, Jianqin; Zhou, Feng; Liu, Jingping] Hunan Univ, State Key Lab Adv Design & Mfg Vehicle Body, Changsha 410082, Peoples R China.;[Yuan, Kainan] China Machinery Int Engn Design & Res Inst Co Ltd, Changsha 410000, Hunan, Peoples R China.
通讯机构：
[Zhou, F ] C;Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Peoples R China.
关键词：
Deep neural networks;Hyperparameter optimization;NO X prediction;Transient cycle;Diesel engine;Population based training
摘要：
Due to the rising environmental concerns, particularly air quality, the emission regulations for non -road mobile machinery are becoming increasingly strict. Real-time emission prediction from diesel engines is significant for emission control and regional pollution estimation. This study aims to develop a machine learning model and optimize its hyperparameters by using a hyperparameter optimization method to NOX emission. Firstly, we collected NOX emission data from test under the non -road transient test cycle (NRTC) and built a significant dataset to choose a best model. Then, the model was trained by dataset and the hyperparameters were automatically optimized by combining Bayesian and Population based training. The accuracy of the optimized was indicated by an R2 value of 0.9784 with the 8 input features. The relative error in the cycle level was 1.3%. Lastly, the quality of NOX emissions during the cycle and the effect of each parameter on NOX emissions were analyzed. The results show that the model is able to predict the real-time concentration changes of NOX more accurately. It can provide a reference for the research and development of emission control technology for nonroad mobile machinery.
摘要：
In this paper, the combustion, heat-work conversion process and emission characteristic at high compression ratio for the spark ignition engine fuelled with E20 (20 % ethanol, 80 % gasoline) fuel were investigated under ultra-lean burn conditions. Specifically, the direct injection (DI) mode combined with port fuel injection (PFI) mode strategy was used in the experiments. In addition, the dual injection strategies were comprehensively investigated by using different fuel injection masses and injection timing. The results indicated that using optimal injection timing and reasonable injection masses can improve heat-work conversion efficiency and combustion efficiency, combustion stability in the test engine. Furthermore, under the lean combustion model, using earlier injection timing could not only inhibit the soot production, but also decrease the nitrogen oxides formation. Compared to the equivalence ratio at 0.82 and DI injection timing at 120 degrees CA bTDC, soot and NOX emissions were respectively reduced by 14.93 %-26.6 % and 39.84 %-73.56 % under the equivalence ratio at 0.685 and DI injection timing at 180 degrees CA bTDC. This study provides an optimization direction for the application of ethanolgasoline blends in the internal combustion engine (ICE) engines for high efficiency and clean combustion.
摘要：
The passive pre-chamber exhibits great potential for practical applications in the internal combustion engine due to its simple structure. However, it faces difficulties in scavenging process, making optimization of pre-chamber structure particularly important. In this study, the effects of pre-chamber ignition systems with different structures and original spark ignition were conducted on a high compression ratio direct-injection SI engine to investigate the combustion, performance, and emission characteristics. The results show that the increase in prechamber volume weakens the in-cylinder combustion process and engine performance, while increasing the prechamber orifice diameter can enhance the combustion stability at medium to high loads, but will weaken the engine performance at low load. Compared to spark ignition, pre-chamber ignition results in an earlier 50% combustion position, a shorter combustion duration and lower COVIMEP, with these effects becoming stronger as load increases. At high load, the pre-chamber ignition (PC1) advances the 50% combustion position by 5.6 degrees CA and shortens the combustion duration by 16.7%. In addition, the indicated thermal efficiency of the pre-chamber ignition achieves an increase of 0.84% at the optimal point and 2.5% at high load. Overall, using the smaller orifice diameter and volume in the pre-chamber can improve in-cylinder combustion process and increase thermal efficiency across the load range. For emission analysis, the pre-chamber ignition leads to an increase in NOx and HC emissions due to the influence of in-cylinder combustion temperature and quenching effect, while the CO emissions are similar to spark ignition.
期刊：
Science of The Total Environment,2024年913:169708 ISSN：0048-9697
通讯作者：
Duan, XB
作者机构：
[Zhou, Feng; Yu, Juan; Wu, Chenghao] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Peoples R China.;[Fu, Jianqin; Zhou, Feng; Liu, Jingping; Duan, Xiongbo] Hunan Univ, Coll Mech & Vehicle Engn, Changsha 410082, Peoples R China.;[Duan, XB; Duan, Xiongbo] Cent South Univ, Sch Energy Sci & Engn, Changsha 410083, Peoples R China.
通讯机构：
[Duan, XB ] C;Cent South Univ, Sch Energy Sci & Engn, Changsha 410083, Peoples R China.
关键词：
Cold start;Combustion;Low carbon fuel;Methanol engine;Regulated and unregulated emissions;Renewable fuel
摘要：
In the context of global carbon neutrality, the internal combustion engines aim to further reduce the carbon emission and improve the fuel economy for the transportation sector. Methanol is treated as a renewable, reliability, and applicability energy, which also shows some superior physicochemical properties compared to the traditional fossil fuels. However, some challenges such as cold start issue, low fuel economy, high unregulated emissions need to address before the methanol widely applies in the engines. This article comprehensively reviews the physicochemical properties and production processes of the methanol, the cold start issue of the methanol engine, and emission and combustion characteristics of the methanol engine for evaluating its potential effect of emission reduction and energy saving in the transportation sector. In addition, different optimization strategies and advanced technologies are proposed and comprehensively discussed in this paper for addressing the issues of the cold start, combustion and emissions of the methanol engines in the real application. Finally, the conclusions and prospects of the methanol engine are presented for promoting its application in the transportation sector and further reducing the carbon emission in the near future, thereby achieving the carbon peak and carbon neutrality in the China.
摘要：
It is well-known that the classical Johnson's Rule leads to optimal schedules on a two-stage flowshop. However, it is still unclear how Johnson's Rule would help in approximation algorithms for scheduling an arbitrary number of parallel two-stage flowshops with the objective of minimizing the makespan. Thus within the paper, we study the problem and propose a new efficient algorithm that incorporates Johnson's Rule applied on each individual flowshop with a carefully designed job assignment process to flowshops. The algorithm is successfully shown to have a runtime O(nlogn)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$O(n \log n)$$\end{document} and an approximation ratio 7/3, where n is the number of jobs. Compared with the recent PTAS result for the problem (Dong et al. in Eur J Oper Res 218(1):16-24, 2020), our algorithm has a larger approximation ratio, but it is more efficient in practice from the perspective of runtime.
摘要：
With the continuous development of deep learning (DL), the task of multimodal dialog emotion recognition (MDER) has recently received extensive research attention, which is also an essential branch of DL. The MDER aims to identify the emotional information contained in different modalities, e.g., text, video, and audio, and in different dialog scenes. However, the existing research has focused on modeling contextual semantic information and dialog relations between speakers while ignoring the impact of event relations on emotion. To tackle the above issues, we propose a novel dialog and event relation-aware graph convolutional neural network (DER-GCN) for multimodal emotion recognition method. It models dialog relations between speakers and captures latent event relations information. Specifically, we construct a weighted multirelationship graph to simultaneously capture the dependencies between speakers and event relations in a dialog. Moreover, we also introduce a self-supervised masked graph autoencoder (SMGAE) to improve the fusion representation ability of features and structures. Next, we design a new multiple information Transformer (MIT) to capture the correlation between different relations, which can provide a better fuse of the multivariate information between relations. Finally, we propose a loss optimization strategy based on contrastive learning to enhance the representation learning ability of minority class features. We conduct extensive experiments on the benchmark datasets, Interactive Emotional Dyadic Motion Capture (IEMOCAP) and Multimodal EmotionLines Dataset (MELD), which verify the effectiveness of the DER-GCN model. The results demonstrate that our model significantly improves both the average accuracy and the F1 value of emotion recognition. Our code is publicly available at https://github.com/yuntaoshou/DER-GCN.
通讯机构：
[Tan, Y ] C;Cent South Univ Forestry & Technol, Changsha, Peoples R China.
摘要：
Medical image description can be applied to clinical medical diagnosis, but the field still faces serious challenges. There is a serious problem of visual and textual data bias in medical datasets, which are the imbalanced distribution of health and disease data. This can greatly affect the learning performance of data-driven neural networks and finally lead to errors in the generated medical image descriptions. To address this problem, we propose a new medical image description network architecture named multimodal data-assisted knowledge fusion network (MDAKF), which introduces multimodal auxiliary signals to guide the Transformer network to generate more accurate medical reports. In detail, audio auxiliary signals provide clear abnormal visual regions to alleviate the visual data bias problem. However, the audio modality signals with similar pronunciation lack recognizability, which may lead to incorrect mapping of audio labels to medical image regions. Therefore, we further fuse the audio with text features as the auxiliary signal to improve the overall performance of the model. Through the experiments on two medical image description datasets, IU-X-ray and COV-CTR, it is found that the proposed model is superior to the previous models in terms of language generation evaluation indicators.
摘要：
A novel cellulose nanofibril/titanate nanofiber modified with CdS quantum dots hydrogel (CTH) was synthesized as an effective, stable, and recyclable photocatalytic adsorbent using cellulose nanofibril (CN), titanate nanofiber (TN), and CdS quantum dots. Within the CTH structure, CN formed an essential framework, creating a three-dimensional (3D) porous structure that enhanced the specific surface area and provided abundant adsorption sites for Cr(VI). Simultaneously, TN modified with CdS quantum dots (TN-CdS) served as a nanoscale Z-type photocatalyst, facilitating the efficient separation of photoinduced electrons and holes, further increasing the photocatalytic efficiency. The morphological, chemical, and optical properties of CTH were thoroughly characterized. The CTH demonstrated the maximum theoretical adsorption capacity of 373.3±14.2mg/g, which was 3.4 times higher than that of CN hydrogel. Furthermore, the photocatalytic reduction rate constant of the CTH was 0.0586±0.0038min(-1), which was 6.4 times higher than that of TN-CdS. Notably, CTH displayed outstanding stability, maintaining 84.9% of its initial removal efficiency even after undergoing five consecutive adsorption-desorption cycles. The remarkable performance of CTH in Cr(VI) removal was attributed to its 3D porous structure, comprising CN and TN-CdS. These findings provide novel insights into developing a stable photocatalytic adsorbent for Cr(VI) removal.
摘要：
Nitrogen (N) is an essential nutrient for ecosystem productivity, restoration and succession processes. Biological N fixation and chemical N addition are both important strategies for accessing N nutrients in soil ecosystem. However, it is unclear which N supplement strategies is more effective in restoring ecosystem stability, partic-ularly in soil micro-food web component, which plays a crucial role in nutrient cycling. Here, an in-situ study was conducted in a natural grassland to investigate the effects of N supply on soil microbial and nematode com-munities by three legume species: Amorpha fruticose (AF), Derris fordii (DF), and Indigofera atropurpurea (IA) at two interplanting densities (1: low density, 1.5 x 2 m; and 2: high density, 1 x 1 m), and by two N fertilization rates (N5: 5 g N m- 2 y-1 and N10: 10 g N m- 2 y-1). Results showed the microbial biomass of total-PLFA, bacteria, fungi, actinomycetes and chlorophyta increased by DF1 and IA2, and the biomasses of total nema-todes, herbivores and omnivores were promoted by AF1, AF2 and DF1, but the biomass of most components was inhibited by N fertilizers. The interactions of soil micro-food web were complicated by DF1 and DF2, but simplified by N5 and N10. Furthermore, different N supplement strategies showed distinct energy flow patterns, such as the bacterial channel was promoted exclusively in AF2, the plant channel was enhanced in AF1 and AF2, and the fungal channel was boosted in DF1 and DF2 but declined in N5 and N10. These results demonstrated that the structure and energy flow of the soil micro-food web might be benefited by legume interplanting but impaired by N fertilizers. In particular, interplanting with D. fordii granted a more sustainable way of N sup-plementation for promoting the complexity and stability of the soil micro-food web, compared to interplanting with other legume species. Our findings provide better understanding of the interactions between legumes and soil biota and have important implications for sustainable restoration of degraded karst grasslands.
摘要：
With the increase in people's living standards, the number of patients suffering from liver injury keeps on increasing. Traditional diagnostic methods can no longer meet the needs of early and accurate diagnosis due to their limitations in application. However, fluorescent probes based on different fluorophores and nanomaterials have been gradually lighting up medical research due to their unique properties, such as high specificity and non-invasiveness. In addition, accurate identification of the different types of liver injury biomarkers can significantly improve the level of early diagnosis. Therefore, this review reviews the fluorescent probes used in the detection of biomarkers of liver injury over recent years and briefly summarizes the corresponding biomarkers of different types of liver injury. Impressively, this review also lists the structures and the response mechanisms of the different probes, and concludes with an outlook, suggesting directions in which improvements can be made. Finally, we hope that this review will contribute to the further development of fluorescent probes for the early diagnosis and assessment of liver injury. With the increase in people's living standards, the number of patients suffering from liver injury keeps on increasing.
摘要：
Screening and identifying the active compounds in foods are important for the development and utilization of functional foods. In this study, the anti-enteritis activity of ethanol extract from Camellia oleifera oil (PECS) was quickly evaluated using a Smurf Drosophila model and the metabolomics approach, combined with molecular docking techniques, were performed to rapidly screen and identify compounds with potential anti-enteritis activity in PECS. PECS showed good anti-enteritis activity and inhibited the activity of 5-lipoxygenase (LOX), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). In particular, wighteone and p-octopamine were newly identified in C. oleifera oil and were proven to have good anti-enteritis activity. The inhibitory activity of kaempferitrin (IC(50) = 0.365 mmol L(-1)) was higher than that of wighteone (IC(50) = 0.424 mmol L(-1)) and p-octopamine (IC(50) = 0.402 mmol L(-1)). Of note, the IC(50) value of salazosulfapyridine was 0.810 mmol L(-1). Inhibition of LOX activity is likely one of the anti-enteritis mechanisms of PECS. These new findings lay the foundation for further investigations into the underlying mechanisms of anti-enteritis activity in C. oleifera oil.
摘要：
Efficient and comprehensive analysis of lipid profiles in yak ghee samples collected from different elevations is crucial for optimal utilization of these resources. Unfortunately, such research is relatively rare. Yak ghee collected from three locations at different altitudes (S2: 2986m; S5: 3671m; S6: 4508m) were analyzed by quantitative lipidomic. Our analysis identified a total of 176 lipids, and 147s lipid of them were upregulated and 29 lipids were downregulated. These lipids have the potential to serve as biomarkers for distinguishing yak ghee from different altitudes. Notably, S2 exhibited higher levels of fatty acids (21:1) and branched fatty acid esters of hydroxy fatty acids (14:0/18:0), while S5 showed increased levels of phosphatidylserine (O-20:0/19:1) and glycerophosphoric acid (19:0/22:1). S6 displayed higher levels of triacylglycerol (17:0/20:5/22:3), ceramide alpha-hydroxy fatty acid-sphingosine (d17:3/34:2), and acyl glucosylceramides (16:0-18:0-18:1). Yak ghee exhibited a high content of neutralizing glycerophospholipids and various functional lipids, including sphingolipids and 21 newly discovered functional lipids. Our findings provide insights into quantitative changes in yak ghee lipids during different altitudes, development of yak ghee products, and screening of potential biomarkers.
期刊：
Building and Environment,2024年249:111127 ISSN：0360-1323
通讯作者：
Deng, QH
作者机构：
[Zhao, Jinping; Wang, Hanqing] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Peoples R China.;[Zhao, Jinping; Wang, Hanqing] Cent South Univ Forestry & Technol, Hunan Engn Res Ctr Full Life Cycle Energy Efficien, Changsha, Peoples R China.;[Ou, Dengsong; Wang, Yan] Cent South Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China.;[Wang, Yan] Wuhan Hanyang Municipal Construct Grp Co Ltd, Wuhan, Peoples R China.;[Li, Yuguo] Univ Hong Kong, Dept Mech Engn, Hong Kong, Peoples R China.
关键词：
Cold exposure;Hypothermia;Body core temperature;Thermoregulatory fatigue;Survival time
摘要：
Background: Extreme temperatures are becoming increasingly common due to global warming. Extreme cold and heat events lead to an increase in mortality rates. More deaths occur in cold weather as a result of hypothermia. However, the change progress of body core temperature and the survival time during cold exposure has yet to be extensively studied. Objectives: To establish a mathematical thermoregulatory model for prolonged cold air exposure and to propose a method for predicting survival time under sedentary conditions. Methods: We extended the classical multi -segment multi -node human thermoregulatory model by considering the effects of thermoregulatory fatigue on shivering and vasoconstriction based on the variable setpoint theory. The core threshold temperatures and the sensitivity of the responses decreased with the degree of fatigue (fa). The model was then used to systematically examine the effects of environmental parameters on the time course of body core temperature in the development of fatal hypothermia. A new wind chill index was constructed based on the simulated data of our thermoregulatory model to estimate the survival time. Results: Our extended thermoregulatory model predicted that during prolonged cold air exposures, body core temperature would decrease in three distinct stages: an initial decrease due to uncompensated cooling load, an equilibrium plateau due to shivering, and a final rapid drop due to thermoregulatory fatigue. Fatal hypothermia occurred at the third stage due to impaired shivering and vasoconstriction caused by fatigue. Lower air temperature and higher air speed can accelerate the occurrence of hypothermia. We proposed a predictive equation for survival time, i.e., the maximum endurance time before fatal hypothermia occurs, which is an exponential function of the wind chill index, and the newly defined wind chill index considers the contribution from both air temperature and air speed. Conclusions: We suggest a new thermoregulatory model to predict the fatal hypothermia due to thermoregulatory fatigue during cold air exposure. We proposed a survival time chart based on a new wind chill index, which can be used to alert the early risk of fatal hypothermia during extreme cold events.
摘要：
Removal of suspended solids (SS) is a prerequisite for delivering clean water. However, removal of ultrafine SS during water purification in a cost-effective manner remains a global challenge. Here we develop an injection-driven filter system that integrates a fully bio-based biodegradable nanofibre hydrogel film with a syringe to remove ultrafine SS for portable and sustainable water purification. The hydrogel film features a densely stacked and entangled nanofibre network, enabling it to reject ultrafine SS with a cut-off size of similar to 10 nm at a similar to 100% rejection efficiency, greatly surpassing commercial filter papers and microporous membranes. During operation, the flux of the injection-driven filter system reaches 90.6 g cm-2 h-1, which is 7.2 times higher than that of commercial polycarbonate ultrafiltration membrane operated under the same conditions. Moreover, this filter system demonstrates good scalability and reusability, with low cost and reduced environmental footprint. The versatility of this filter system is further proven by successful clean water production from various difficult-to-purify water resources, including muddy water, river water, dirty water from melted snow and nanoplastic-contaminated water. Overall, this work provides a facile yet cost-effective tool for sustainable water purification. Removal of ultrafine suspended solids from contaminated water in a cost-effective manner remains a global challenge. Here the authors develop an injection-driven filter system that is based on a fully bio-based biodegradable nanofibre hydrogel film to achieve such a goal.
作者机构：
[Chen, Yingkang; Fu, Junwei; Wang, Jun; Liu, Min; Luo, Tao; Liao, Wanru; Wang, Qiyou; Liu, M; Li, Hongmei; Wang, Xiqing; Liu, Kang; Ni, Ganghai] Cent South Univ, Hunan Joint Int Res Ctr Carbon Dioxide Resource Ut, Sch Phys, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Liu, Changxu] Univ Exeter, Ctr Metamaterial Res & Innovat, Dept Engn, Exeter EX4 4QF, England.;[Wang, Yanqiu; Li, Wenzhang; Chen, Shanyong] Cent South Univ, Sch Chem & Chem Engn, Changsha 410083, Peoples R China.;[Chan, Ting-Shan] Natl Synchrotron Radiat Res Ctr, Hsinchu 300092, Taiwan.;[Ma, Chao] Hunan Univ, Coll Mat Sci & Engn, Changsha 410082, Peoples R China.
通讯机构：
[Liu, M ; Xi, BD ; Fu, JW] C;Cent South Univ, Hunan Joint Int Res Ctr Carbon Dioxide Resource Ut, Sch Phys, State Key Lab Powder Met, Changsha 410083, Peoples R China.;Chinese Res Inst Environm Sci, State Key Lab Environm Criteria & Risk Assessment, Beijing 100012, Peoples R China.
摘要：
Nitrate (NO(3)(‒)) pollution poses significant threats to water quality and global nitrogen cycles. Alkaline electrocatalytic NO(3)(‒) reduction reaction (NO(3)RR) emerges as an attractive route for enabling NO(3)(‒) removal and sustainable ammonia (NH(3)) synthesis. However, it suffers from insufficient proton (H(+)) supply in high pH conditions, restricting NO(3)(‒)-to-NH(3) activity. Herein, we propose a halogen-mediated H(+) feeding strategy to enhance the alkaline NO(3)RR performance. Our platform achieves near-100% NH(3) Faradaic efficiency (pH = 14) with a current density of 2 A cm(-2) and enables an over 99% NO(3)(-)-to-NH(3) conversion efficiency. We also convert NO(3)(‒) to high-purity NH(4)Cl with near-unity efficiency, suggesting a practical approach to valorizing pollutants into valuable ammonia products. Theoretical simulations and in situ experiments reveal that Cl-coordination endows a shifted d-band center of Pd atoms to construct local H(+)-abundant environments, through arousing dangling O-H water dissociation and fast *H desorption, for *NO intermediate hydrogenation and finally effective NO(3)(‒)-to-NH(3) conversion.
关键词：
Heavy metals;Magnetic material;Matrix effect;Multiple-ion adsorption;Trace concentration
摘要：
A one-pot synthesis afforded a magnetic, crosslinked polymer adsorbent (m-P6) with a variety of functional groups to realize simultaneous adsorption of Cd(2+), Pb(2+), Hg(2+), and As(3+). The material was characterized by TEM-EDS, XRD, FT-IR, VSM, and XPS. Kinetic and isothermal analyses suggested mainly chemisorption processes of heavy metal ions that form multiple layers on heterogeneous surfaces. Theoretical adsorption capacities calculated by a pseudo-2nd-order kinetic model and the Sips isothermal model were 282.88mg/g for Cd(2+), 326.18mg/g for Pb(2+), 117.85mg/g for Hg(2+), and 320.29mg/g for As(3+). m-P6 not only can efficiently adsorb divalent heavy metals (Cd(2+), Pb(2+), Hg(2+)), but also demonstrate a process of adsorption-driven catalytic oxidation by single-electron transfer (SET) from As(3+) to As(5+). In application, in addition to adsorption in water, m-P6 is capable of minimizing matrix interference, and extracting trace heavy metals in a complex environment (cereal) through easy operations for improving the detection accuracy, as well as it is potential for application in detection of trace heavy metals in foodstuffs. m-P6 can be readily regenerated and efficiently recycled for 5 cycles using eluent E12 and dilute acid.
