| 1. |
- Dai, Junxi, et al.
(författare)
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Promoted Sb removal with hydrogen production in microbial electrolysis cell by ZIF-67-derived modified sulfate-reducing bacteria bio-cathode
- 2023
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Ingår i: Science of the Total Environment. - : ELSEVIER. - 0048-9697 .- 1879-1026. ; 856
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Tidskriftsartikel (refereegranskat)abstract
- Bio-cathode Microbial electrolysis cell (MEC) has been widely discovered for heavy metals removal and hydrogen production. However, low electron transfer efficiency and heavy metal toxicity limit MEC treatment efficiency. In this study, ZIF-67 was introduced to modify Sulfate-reducing bacteria (SRB) bio-cathode to enhance the bioreduction of sulfate and Antimony (Sb) with hydrogen production in the MEC. ZIF-67 modified bio-cathode was developed from a bio-anode microbial fuel cell (MFC) by operating with an applied voltage of 0.8 V to reverse the polarity. Cyclic voltammetry, linear sweep voltammetry and electrochemical impedance were done to confirm the performance of the ZIF67 modified SRB bio-cathode. The synergy reduction of sulfate and Sb was accomplished by sulfide metal precipitation reaction from SRB itself. Maximum sulfate reduction rate approached 93.37 % and Sb removal efficiency could reach 92 %, which relies on the amount of sulfide concentration generated by sulfate reduction reaction, with 0.923 +/- 0.04 m(3) H-2/m(3) of hydrogen before adding Sb and 0.857 m(3) H-2/m(3) of hydrogen after adding Sb. The hydrogen was mainly produced in this system and the result of gas chromatography (GC) indicated that 73.27 % of hydrogen was produced. Meanwhile the precipitates were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy to confirm Sb2S3 was generated from Sb (V).
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| 2. |
- Dai, Yi, et al.
(författare)
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Zn-doped CaFeO3 perovskite-derived high performed catalyst on oxygen reduction reaction in microbial fuel cells
- 2021
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 489
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Tidskriftsartikel (refereegranskat)abstract
- Stable perovskite oxide is considered as a potential cathode for microbial fuel cells (MFCs). Herein, Zn is used as an effective element to modify the micro-structure and oxygen vacancy of perovskite to be a novel cathode catalyst. Physical characterizations show that due to partial volatilization at high temperature of Zn, perovskite forms hierarchically porous structures. Moreover, Zn is precipitated in electrochemical reaction to generate Zn vacancy in situ; thus, the active center of Fe has a superior interaction with oxygen-containing species, promoting the production of oxygen vacancy and forms a mixed valence state of Fe2+/Fe3+. The Zn-doped perovskite material CaFe0.7Zn0.3O3 exhibits remarkable oxygen reduction reaction (ORR) performances with outstanding onset potential (0.194 V vs. Ag/AgCl) and half-wave potential (-0.219 V vs. Ag/AgCl) under alkaline condition, which is better than Pt/C catalyst. Besides, CaFe0.7Zn0.3O3 shows an excellent four-electron pathway of ORR mechanism with remarkable corrosion resistance and stability, which enables a more reliable cathode electrocatalyst. The maximum power density of CaFe0.7Zn0.3O3 (892.10 +/- 90.79 mW m(-3)) testing on microbial fuel cell is comparable to the maximum power density (1012.86 +/- 84.03 mW m(-3)) of Pt/C. The findings of this work provide the feasibility of exploring inexpensive and high-performance cathode catalyst.
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| 3. |
- Paul, Neelima, et al.
(författare)
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Real-time observation of nucleation and growth of Au on CdSe quantum dot templates
- 2021
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductor quantum dot (QD) arrays can be useful for optical devices such as lasers, solar cells and light-emitting diodes. As the size distribution influences the band-gap, it is worthwhile to investigate QDs prepared using different solvents because each of them could influence the overall morphology differently, depending on the ligand network around individual QDs. Here, we follow the nucleation and growth of gold (Au) on CdSe QD arrays to investigate the influence of surface ligands and thereby realized interparticle distance between QDs on Au growth behaviour. We particularly emphasize on the monolayer stage as the Au decoration on individual QDs is expected at this stage. Therefore, we sputter-deposit Au on each QD array to investigate the morphological evolution in real-time using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). The growth kinetics - independent of the template - signifies that the observed template-mediated nucleation is limited only to the very first few monolayers. Delicate changes in the Au growth morphology are seen in the immediate steps following the initial replicated decoration of the QD arrays. This is followed by a subsequent clustering and finally a complete Au coverage of the QD arrays.
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| 4. |
- Sui, Zhongyi, et al.
(författare)
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An improved approach for assessing marine traffic complexity based on Voronoi diagram and complex network
- 2022
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Ingår i: Ocean Engineering. - : Elsevier BV. - 0029-8018 .- 1873-5258. ; 266, s. 112884-
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Tidskriftsartikel (refereegranskat)abstract
- The shipping industry is constantly expanding, and maritime traffic is increasing in numerous navigable waters. For maritime traffic safety, improving Situation Awareness (SA) is critical. However, the majority of relevant research placed a greater emphasis on the risk of a collision between two ships, but failed to capture the complexity of the global traffic situation. In this paper, a framework for evaluating marine traffic complexity is developed. With the combination of the Voronoi diagram and complex network, an improved Marine Traffic Complex Network (MTSCN) is coming into being. The geometric features of Voronoi diagram are used to divide the water area into multiple cells, setting safe distances is avoided by treating ships as neighbors and other ships. The impact of neighbors on the situation awareness and the impact of other ships on the collision risk of own ship are considered. This method can more truly demonstrate the traffic complexity in the water area. Simulations are introduced to investigate the validity of the proposed method with two ships crossing situation, three ships crossing situation and four ships crossing situation. The proposed method is further demonstrated using actual AIS data in the Yangtze River, and the correlation between complexity and other indicators has been analyzed. The result shows that the improved MTSCN may give an intuitive and accessible measure to capture the essence of maritime traffic, which will be helpful in understanding, monitoring, and controlling maritime traffic safety in the future. Additionally, the complexity based on MTSCN could enhance the SA of VTSOs by supporting decision-making.
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