Four Mg-x Zn-y Sn(x=2,4 and y=1,3 wt.%)alloys are investigated as anode materials for magnesium-air(Mg-air)battery.The self-corrosion and battery discharge behavior of these four Mg-Zn-Sn alloys are analyzed by electr...Four Mg-x Zn-y Sn(x=2,4 and y=1,3 wt.%)alloys are investigated as anode materials for magnesium-air(Mg-air)battery.The self-corrosion and battery discharge behavior of these four Mg-Zn-Sn alloys are analyzed by electrochemical measurements and Mg-air battery tests.The results show that addition of Sn stimulates the electrochemical activity and significantly improves the anodic efficiency and specific capacity of Mg-Zn alloy anodes.Among the four alloy anodes,Mg-2Zn-3Sn(ZT23)shows the best battery discharge performance at low current densities(≤5 m A cm^(-2)),achieving high energy density of 1367 m Wh g^(-1)at 2 mA cm^(-2).After battery discharging,the surface morphology and electrochemical measurement results illustrate that a ZnO and SnO/SnO_(2)mixed film on alloy anode surface decreases self-corrosion and improves anodic efficiency during discharging.The excessive intermetallic phases lead to the failure of passivation films,acting as micro-cathodes to accelerate self-corrosion.展开更多
The local environment of Cu atoms in Fe73.5Cu1Nb3Si13.5B9 alloy was investigated by extended X-ray absorption fine structure(EXAFS).Cu clusters began to order when the annealing temperature was around 733 K from the r...The local environment of Cu atoms in Fe73.5Cu1Nb3Si13.5B9 alloy was investigated by extended X-ray absorption fine structure(EXAFS).Cu clusters began to order when the annealing temperature was around 733 K from the results of the Fourier transform curves.The fitting results showed that the first shell of the near fcc(face-centered cubic)Cu clusters only contained Cu atoms.The coordination number increased with the annealing temperature.Subsequently,the occupancy rate increased from 33.3%(annealed at 733 K)to 100% (annealed at 853 K).This local structural change of Cu atoms could probably affect the distribution of the bcc(body-centered cubic)α-Fe in Fe73.5Cu1Nb3Si13.5B9 alloy.展开更多
The study was performed for removing ibuprofen from water using ozonation with visible light SrWO4/ZnO catalyst.For the removal of Ibuprofen,the overall reaction was carried out in a glass reactor in the presence of U...The study was performed for removing ibuprofen from water using ozonation with visible light SrWO4/ZnO catalyst.For the removal of Ibuprofen,the overall reaction was carried out in a glass reactor in the presence of UV light and constant supply of ozone.The maximum removal efficiency of Ibuprofen was 93%at 0.1 mg/L initial Ibuprofen concentration,and 0.35 g/L catalyst concentration keeping the contact time 30 min.After a certain value,an increase in a concentration of doping agent,catalyst as well as initial Ibuprofen concentration results in a decrease of efficiency of the process.The prepared photo catalysts were characterized by X-ray diffraction,FTIR spectra and SEM analysis.XRD peaks and FTIR spectra has clearly shown that the doping of SrWO4 with ZnO showed better result as compared to individual.SEM analysis showed that they spherical nano-composite crystals were dominant in character.BOD character was found to reduce after ozonation of solution.Various by products were formed and were identified through GC-MS analysis.From results,it was found that combination of SrWO4/ZnO was able to remove 93%of ibuprofen and 0.4%dopping of ZnO on SrWO4 was found to be sufficient.Degradation pattern of by products were identitified in GC-MS with various mass ratios as 177,92,57,44.Nearly 55%removal of BOD was observed in this study.This study was found to be useful for removal of pharmaceuticals and other similar pollutants from water effectively.展开更多
Declining worldwide phosphate rock reserves has driven a growing interest in exploration of alternative phosphate supplies. This study involved phosphorus recovery from swine wastewater through precipitation of struvi...Declining worldwide phosphate rock reserves has driven a growing interest in exploration of alternative phosphate supplies. This study involved phosphorus recovery from swine wastewater through precipitation of struvite, a valuable slow-release fertiliser. The economic feasibility of this process is highly dependent on the cost of magnesium source. Two different magnesium sources were used for phosphorus recovery: pure magnesium chloride and nanofiltration(NF) saline water retentate. The paper focuses on the impact of ionic strength on phosphorus recovery performance that has not been reported elsewhere. Experimental design with five numerical variables(Mg/P molar ratio, pH, PO_(4)^(3-)-P, NH_(4)^(+)-N, and Ca^(2+) levels) and one categorical variable(type of magnesium source) was used to evaluate the effect of ionic strength on phosphorus removal and struvite purity. The experimental data were analysed using analysis of variance(ANOVA) and principal component analysis(PCA). Results indicated that a magnesium source obtained from NF retentate was as effective as MgCl_(2) for struvite precipitation. It was also revealed that ionic strength had a more positive effect on struvite purity than on phosphorus removal. Within the range of parameters studied in this research, high ionic strength, high p H and wastewater with high phosphate, high ammonium and low calcium contents were found to be the most favourable conditions for struvite precipitation. Findings from this study will be beneficial to determine the feasibility of using high ionic strength saline water, such as NF seawater retentate, as a magnesium source for phosphorus recovery from wastewater that is rich in ammoniumnitrogen and phosphate.展开更多
The synthesis of nonaqueous peracetic acid inacetone by acetaldehyde oxidation was carried out in atubular packed reactor. The influencing factors of thereacting system including packing material, oxygen carrier,and r...The synthesis of nonaqueous peracetic acid inacetone by acetaldehyde oxidation was carried out in atubular packed reactor. The influencing factors of thereacting system including packing material, oxygen carrier,and reactor configuration were investigated. Theresults show that porous materials are inappropriate forperacetic acid synthesis and only non porous materialwith appropriate surface area can provide good peraceticacid selectivity and yield. Among the six kinds of packingmaterial investigated, SA-5118 is the best one. As oxidizinggas, pure oxygen is superior to air. The optimumlength-to-inner diameter ratio of the reactor is about 40.Under the proper reaction conditions, the highest peraceticacid yield of 84.15% and the highest selectivity of93.34% can be achieved which indicates that the novelreacting system is effective and economical for nonaqueousperacetic acid production.展开更多
Self-healing hydrogels have attracted growing attention over the past decade due to their biomimetic structure,biocompatibility,as well as enhanced lifespan and reliability,thereby have been widely used in various bio...Self-healing hydrogels have attracted growing attention over the past decade due to their biomimetic structure,biocompatibility,as well as enhanced lifespan and reliability,thereby have been widely used in various biomedical,electrical and environmental engineering applications.This feature article has reviewed our recent progress in self-healing hydrogels derived from mussel-inspired interactions,multiple hydrogen-bonding functional groups such as 2-ureido-4[1H]-pyrimidinohe(UPy),dynamic covalent bonds(eg,Schiff base reactions and boronic ester bonds).The underlying molecular basics of these interactions,hydrogel preparation principles,and corresponding performances and applications are introduced.The underlying reversible intermolecular interaction mechanisms in these hydrogels were investigated using nanomechanical techniques such as surface forces apparatus(SFA)and atomic force microscopy(AFM),providing fundamental insights into the self-healing mechanisms of the hydrogels.The remaining challenging issues and perspectives in this rapidly developing research area are also discussed.展开更多
基金partially supported by the Marsden Fund managed by the Royal Society of New Zealand Te Apārangi(FastStart Marsden Grant project No.UOA1817)the scholarship from China Scholarship Council(No.201808060410)
文摘Four Mg-x Zn-y Sn(x=2,4 and y=1,3 wt.%)alloys are investigated as anode materials for magnesium-air(Mg-air)battery.The self-corrosion and battery discharge behavior of these four Mg-Zn-Sn alloys are analyzed by electrochemical measurements and Mg-air battery tests.The results show that addition of Sn stimulates the electrochemical activity and significantly improves the anodic efficiency and specific capacity of Mg-Zn alloy anodes.Among the four alloy anodes,Mg-2Zn-3Sn(ZT23)shows the best battery discharge performance at low current densities(≤5 m A cm^(-2)),achieving high energy density of 1367 m Wh g^(-1)at 2 mA cm^(-2).After battery discharging,the surface morphology and electrochemical measurement results illustrate that a ZnO and SnO/SnO_(2)mixed film on alloy anode surface decreases self-corrosion and improves anodic efficiency during discharging.The excessive intermetallic phases lead to the failure of passivation films,acting as micro-cathodes to accelerate self-corrosion.
基金supported by the National Natural Science Foundation of China(Grant No.51071109)the Young Excellent Talents in Tongji University(Grant No.2009KJ003)
文摘The local environment of Cu atoms in Fe73.5Cu1Nb3Si13.5B9 alloy was investigated by extended X-ray absorption fine structure(EXAFS).Cu clusters began to order when the annealing temperature was around 733 K from the results of the Fourier transform curves.The fitting results showed that the first shell of the near fcc(face-centered cubic)Cu clusters only contained Cu atoms.The coordination number increased with the annealing temperature.Subsequently,the occupancy rate increased from 33.3%(annealed at 733 K)to 100% (annealed at 853 K).This local structural change of Cu atoms could probably affect the distribution of the bcc(body-centered cubic)α-Fe in Fe73.5Cu1Nb3Si13.5B9 alloy.
基金the Institutional Fund Projects under grant no.(IFPRC-078-135-2020)。
文摘The study was performed for removing ibuprofen from water using ozonation with visible light SrWO4/ZnO catalyst.For the removal of Ibuprofen,the overall reaction was carried out in a glass reactor in the presence of UV light and constant supply of ozone.The maximum removal efficiency of Ibuprofen was 93%at 0.1 mg/L initial Ibuprofen concentration,and 0.35 g/L catalyst concentration keeping the contact time 30 min.After a certain value,an increase in a concentration of doping agent,catalyst as well as initial Ibuprofen concentration results in a decrease of efficiency of the process.The prepared photo catalysts were characterized by X-ray diffraction,FTIR spectra and SEM analysis.XRD peaks and FTIR spectra has clearly shown that the doping of SrWO4 with ZnO showed better result as compared to individual.SEM analysis showed that they spherical nano-composite crystals were dominant in character.BOD character was found to reduce after ozonation of solution.Various by products were formed and were identified through GC-MS analysis.From results,it was found that combination of SrWO4/ZnO was able to remove 93%of ibuprofen and 0.4%dopping of ZnO on SrWO4 was found to be sufficient.Degradation pattern of by products were identitified in GC-MS with various mass ratios as 177,92,57,44.Nearly 55%removal of BOD was observed in this study.This study was found to be useful for removal of pharmaceuticals and other similar pollutants from water effectively.
基金This research was financially supported by the Department of Chemical and Materials Engineering,Faculty of Engineering,the University of Auckland。
文摘Declining worldwide phosphate rock reserves has driven a growing interest in exploration of alternative phosphate supplies. This study involved phosphorus recovery from swine wastewater through precipitation of struvite, a valuable slow-release fertiliser. The economic feasibility of this process is highly dependent on the cost of magnesium source. Two different magnesium sources were used for phosphorus recovery: pure magnesium chloride and nanofiltration(NF) saline water retentate. The paper focuses on the impact of ionic strength on phosphorus recovery performance that has not been reported elsewhere. Experimental design with five numerical variables(Mg/P molar ratio, pH, PO_(4)^(3-)-P, NH_(4)^(+)-N, and Ca^(2+) levels) and one categorical variable(type of magnesium source) was used to evaluate the effect of ionic strength on phosphorus removal and struvite purity. The experimental data were analysed using analysis of variance(ANOVA) and principal component analysis(PCA). Results indicated that a magnesium source obtained from NF retentate was as effective as MgCl_(2) for struvite precipitation. It was also revealed that ionic strength had a more positive effect on struvite purity than on phosphorus removal. Within the range of parameters studied in this research, high ionic strength, high p H and wastewater with high phosphate, high ammonium and low calcium contents were found to be the most favourable conditions for struvite precipitation. Findings from this study will be beneficial to determine the feasibility of using high ionic strength saline water, such as NF seawater retentate, as a magnesium source for phosphorus recovery from wastewater that is rich in ammoniumnitrogen and phosphate.
基金the financial support of the Department of Science and Technology of Guangdong Province(China)(Project 2005A40201002)the University of Alberta(Canada)for providing a fellowship to one of the authors.Dr.T Y Zhang,Prof.L.Zhong,Prof.H.B.Fan are grateful to Professor K.Chuang for his help in his laboratory of the Department of Chemical and Materials Engineering in the University of Alberta.
文摘The synthesis of nonaqueous peracetic acid inacetone by acetaldehyde oxidation was carried out in atubular packed reactor. The influencing factors of thereacting system including packing material, oxygen carrier,and reactor configuration were investigated. Theresults show that porous materials are inappropriate forperacetic acid synthesis and only non porous materialwith appropriate surface area can provide good peraceticacid selectivity and yield. Among the six kinds of packingmaterial investigated, SA-5118 is the best one. As oxidizinggas, pure oxygen is superior to air. The optimumlength-to-inner diameter ratio of the reactor is about 40.Under the proper reaction conditions, the highest peraceticacid yield of 84.15% and the highest selectivity of93.34% can be achieved which indicates that the novelreacting system is effective and economical for nonaqueousperacetic acid production.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)the Canada Research Chairs program.
文摘Self-healing hydrogels have attracted growing attention over the past decade due to their biomimetic structure,biocompatibility,as well as enhanced lifespan and reliability,thereby have been widely used in various biomedical,electrical and environmental engineering applications.This feature article has reviewed our recent progress in self-healing hydrogels derived from mussel-inspired interactions,multiple hydrogen-bonding functional groups such as 2-ureido-4[1H]-pyrimidinohe(UPy),dynamic covalent bonds(eg,Schiff base reactions and boronic ester bonds).The underlying molecular basics of these interactions,hydrogel preparation principles,and corresponding performances and applications are introduced.The underlying reversible intermolecular interaction mechanisms in these hydrogels were investigated using nanomechanical techniques such as surface forces apparatus(SFA)and atomic force microscopy(AFM),providing fundamental insights into the self-healing mechanisms of the hydrogels.The remaining challenging issues and perspectives in this rapidly developing research area are also discussed.
