The feasibility of copper recovery by induced crystallization in a long period（174 days） was investigated in a seeded fluidized bed reactor（FBR）. The process was divided into 3 periods according to different influ...The feasibility of copper recovery by induced crystallization in a long period（174 days） was investigated in a seeded fluidized bed reactor（FBR）. The process was divided into 3 periods according to different influent conditions, and the period Ⅲ was separated into Ⅲ-a and Ⅲb due to the adjustment of the molar ratio of CO3^2- concentration to copper concentration（[CT]/[Cu^2＋]）. The removal efficiency could exceed 95% and the average effluent copper concentration decreased to 3.0 mg/L. The mean particle size of seed grains with copper crystals coating on, raised to 0.36 mm from initial 0.18 mm. During period Ⅲ-a, the supersaturation exceeded 2.88 × 104, the removal efficiency decreased to 60%–80% and the particle size dropped to 0.30 mm, due to the generation of fines by homogeneous crystallization and seeds breaking. And the morphology of the crystals on the seed grains changed from rod-like to spherical which lead to the particle size decreasing. In period Ⅲ-b,the supersaturation was modified by adjusting the molar ratio of [CT]/[Cu^2＋] to 1.2 from 2.The efficiency was back to 95% and the mean particle size grew to 0.36 mm at the end of Ⅲb, the crystals coating on the seeds turned back to rod-like products of good stability. This study illustrated that the copper salt crystal could keep on growing on the seed grains for over 150 days, the feasibility and controllability of copper recovery by induced crystallization process in FBR were satisfactory, even under the dramatic changes in influent conditions.展开更多
Although defect engineering opens up new opportunities in the field of gas sensors,the introduction of defects to enhance the gas sensing properties of metal oxide semiconductors(MOSs)has long been neglected.In this r...Although defect engineering opens up new opportunities in the field of gas sensors,the introduction of defects to enhance the gas sensing properties of metal oxide semiconductors(MOSs)has long been neglected.In this review,defect engineering strategies have been systematically introduced,with a focus on employing them for improved gas sensing performances.To keep the subject focused,we take SnO_(2) nanomaterials as an example.Various synthesis methods for defective SnO_(2),including ion/electron/ray/laser-beam irradiation,plasma treatment,heating protocol,chemical reduction,tailoring specially exposed crystal facets and atoms doping,are emphasized.Different roles of defects on the gas sensing process of SnO_(2) are discussed.Finally,critical issues and future directions of defect engineering are presented.This paper provides a platform for better understanding the relationships between synthesis,defect types and gas sensing performances of MOSs.It is also expected to unpack an important research direction for controlled synthesis of defective nanomaterials with other applications,including advanced energy conversion and storage.展开更多
A rapid deactivation of TiO2 film was observed in the process of the photocatalytic degradation of formic acid in the presence of Cu(II) due to the deposition of Cu(0). A novel regeneration method, air-assisted elect...A rapid deactivation of TiO2 film was observed in the process of the photocatalytic degradation of formic acid in the presence of Cu(II) due to the deposition of Cu(0). A novel regeneration method, air-assisted electrooxidation, could efficiently retrieve the photocatalytic activity of the deact ivated film. HNO3 medium has a regeneration extent of 97.2% for first run, much higher than that of HCl and H2SO4 mediums.展开更多
Highly sensitive,fast and low-temperature detection of triethylamine(TEA)gas based on SnO_(2) is attractive yet remains challenging.Herein,SnS_(2) nanosheets(NSs)/SnO_(2) hollow multishelled structures(HoMSs)-based se...Highly sensitive,fast and low-temperature detection of triethylamine(TEA)gas based on SnO_(2) is attractive yet remains challenging.Herein,SnS_(2) nanosheets(NSs)/SnO_(2) hollow multishelled structures(HoMSs)-based sensors are designed by the synthesis of SnO_(2) HoMSs,followed by in situ sulfuration with thioacetamide.By varying the thioacetamide levels,Sn S_(2)/SnO_(2) heterostructures with different SnS_(2) contents were obtained and their TEA gas sensing performances were investigated.展开更多
In this paper, we mainly focus on the Riesz means of eigenvalues of the subelliptic Laplacian on the Heisenberg group Hn. We establish a trace formula of associated eigenvalues, then we prove differential inequalities...In this paper, we mainly focus on the Riesz means of eigenvalues of the subelliptic Laplacian on the Heisenberg group Hn. We establish a trace formula of associated eigenvalues, then we prove differential inequalities, difference inequalities and monotonicity formulas for the Riesz means of eigenvalues of the subelliptic Laplacian.展开更多
Supercapacitors(SCs)with high power output have attracted increasing attention as efficient and environmentally friendly energy storage devices.Prussian blue and its analogues(PB/PBAs)are simple coordination polymers ...Supercapacitors(SCs)with high power output have attracted increasing attention as efficient and environmentally friendly energy storage devices.Prussian blue and its analogues(PB/PBAs)are simple coordination polymers with tunable chemical compositions and open framework.Prussian blue can act as electrode materials in its pristine form and has also been utilized to derive various metallic nanostructures for electrochemical applications due to their simple fabrication process,non-toxic characteristics,and low price.Here,we firstly describe the charge storage mechanisms of SCs briefly followed by an introduction of the fabrication methods of PB/PBAs and their derivatives.Then,a comprehensive review on recent studies of the use of PB/PBAs and their derivatives as the electrode materials for SCs are given with a focus on strategies to improve their electrochemical performances.Finally,we discuss critical challenges in this research area and propose some general ideas for future research.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21307072 and 51508303)the Joint Program of Beijing Natural Science Foundation and Beijing Academy of Science and Technology(No.L140011)the Tsinghua University Initiative Scientific Research Program(No.20121087922)
文摘The feasibility of copper recovery by induced crystallization in a long period（174 days） was investigated in a seeded fluidized bed reactor（FBR）. The process was divided into 3 periods according to different influent conditions, and the period Ⅲ was separated into Ⅲ-a and Ⅲb due to the adjustment of the molar ratio of CO3^2- concentration to copper concentration（[CT]/[Cu^2＋]）. The removal efficiency could exceed 95% and the average effluent copper concentration decreased to 3.0 mg/L. The mean particle size of seed grains with copper crystals coating on, raised to 0.36 mm from initial 0.18 mm. During period Ⅲ-a, the supersaturation exceeded 2.88 × 104, the removal efficiency decreased to 60%–80% and the particle size dropped to 0.30 mm, due to the generation of fines by homogeneous crystallization and seeds breaking. And the morphology of the crystals on the seed grains changed from rod-like to spherical which lead to the particle size decreasing. In period Ⅲ-b,the supersaturation was modified by adjusting the molar ratio of [CT]/[Cu^2＋] to 1.2 from 2.The efficiency was back to 95% and the mean particle size grew to 0.36 mm at the end of Ⅲb, the crystals coating on the seeds turned back to rod-like products of good stability. This study illustrated that the copper salt crystal could keep on growing on the seed grains for over 150 days, the feasibility and controllability of copper recovery by induced crystallization process in FBR were satisfactory, even under the dramatic changes in influent conditions.
基金supported by the National Natural Science Foundation of China(No.51872173)the Taishan Scholars Program of Shandong Province,China(No.tsqn201812068)+3 种基金the Opening Fund of State Key Laboratory of Heavy Oil Processing,China(No.SKLOP202002006)the Higher School Youth Innovation Team of Shandong Province,China(No.2019KJA013)the Science and Technology Special Project of Qingdao City,Shandong Province,China(No.20-3-4-3-nsh)financial support provided by the Natural Science Foundation of Shandong Province,China(No.ZR2021QE092).
文摘Although defect engineering opens up new opportunities in the field of gas sensors,the introduction of defects to enhance the gas sensing properties of metal oxide semiconductors(MOSs)has long been neglected.In this review,defect engineering strategies have been systematically introduced,with a focus on employing them for improved gas sensing performances.To keep the subject focused,we take SnO_(2) nanomaterials as an example.Various synthesis methods for defective SnO_(2),including ion/electron/ray/laser-beam irradiation,plasma treatment,heating protocol,chemical reduction,tailoring specially exposed crystal facets and atoms doping,are emphasized.Different roles of defects on the gas sensing process of SnO_(2) are discussed.Finally,critical issues and future directions of defect engineering are presented.This paper provides a platform for better understanding the relationships between synthesis,defect types and gas sensing performances of MOSs.It is also expected to unpack an important research direction for controlled synthesis of defective nanomaterials with other applications,including advanced energy conversion and storage.
文摘A rapid deactivation of TiO2 film was observed in the process of the photocatalytic degradation of formic acid in the presence of Cu(II) due to the deposition of Cu(0). A novel regeneration method, air-assisted electrooxidation, could efficiently retrieve the photocatalytic activity of the deact ivated film. HNO3 medium has a regeneration extent of 97.2% for first run, much higher than that of HCl and H2SO4 mediums.
基金supported by the National Natural Science Foundation of China(Nos.51872173 and 52202176)the Natural Science Foundation of Shandong Province(Nos.ZR2022JQ21and ZR2021QE092)+2 种基金the Opening Fund of State Key Laboratory of Heavy Oil Processing(No.SKLOP202002006)Higher School Youth Innovation Team of Shandong Province(No.2019KJA013)Science and Technology Special Project of Qingdao City(No.20-3-4-3-nsh)。
文摘Highly sensitive,fast and low-temperature detection of triethylamine(TEA)gas based on SnO_(2) is attractive yet remains challenging.Herein,SnS_(2) nanosheets(NSs)/SnO_(2) hollow multishelled structures(HoMSs)-based sensors are designed by the synthesis of SnO_(2) HoMSs,followed by in situ sulfuration with thioacetamide.By varying the thioacetamide levels,Sn S_(2)/SnO_(2) heterostructures with different SnS_(2) contents were obtained and their TEA gas sensing performances were investigated.
文摘In this paper, we mainly focus on the Riesz means of eigenvalues of the subelliptic Laplacian on the Heisenberg group Hn. We establish a trace formula of associated eigenvalues, then we prove differential inequalities, difference inequalities and monotonicity formulas for the Riesz means of eigenvalues of the subelliptic Laplacian.
基金supported by the National Natural Science Foundation of China(Nos.51672055,51972342,51872656,and 51702275)Taishan Scholar Project of Shandong Province(ts20190922)Key Basic Research Project of Natural Science Foundation of Shandong Province(ZR2019ZD51)
文摘Supercapacitors(SCs)with high power output have attracted increasing attention as efficient and environmentally friendly energy storage devices.Prussian blue and its analogues(PB/PBAs)are simple coordination polymers with tunable chemical compositions and open framework.Prussian blue can act as electrode materials in its pristine form and has also been utilized to derive various metallic nanostructures for electrochemical applications due to their simple fabrication process,non-toxic characteristics,and low price.Here,we firstly describe the charge storage mechanisms of SCs briefly followed by an introduction of the fabrication methods of PB/PBAs and their derivatives.Then,a comprehensive review on recent studies of the use of PB/PBAs and their derivatives as the electrode materials for SCs are given with a focus on strategies to improve their electrochemical performances.Finally,we discuss critical challenges in this research area and propose some general ideas for future research.
