Abstract Chinese air pollution has increased in this century along with the rapid socioeconomic development and resulting anthropogenic emissions. While recent emission control measures have shown encouraging re sults...Abstract Chinese air pollution has increased in this century along with the rapid socioeconomic development and resulting anthropogenic emissions. While recent emission control measures have shown encouraging re sults and have reduced the levels of sulfur dioxide and primary aerosols, the concentrations of other air pollutants continue to grow, particularly secondary pollutants in cluding ozone and secondary aerosols. Meanwhile, a va riety of intentional and unintentional socioeconomic events have temporarily changed the pace, and even the signs, of growth of air pollution. These events include the short-term emission restrictions imposed during the Sino-African Summit, the Beijing Olympics and Para lympics, the Shanghai World Exposition （Shanghai Expo）, the Guangzhou Asian Olympics, and the Shenzhen Uni versiade, as well as the unintentional emission reductions associated with the recent economic recession and the annual Chinese New Year. This paper presents a brief overview of trends and temporary perturbations of Chi nese air pollution since 2000, summarizing studies on anthropogenic emission inventories, atmospheric meas urements, and inverse modeling. It concludes with rec ommendations for future research.展开更多
Nitrate is the leading cause of eutrophication worldwide and is one of the most challenging pollutants for restoration of polluted surface waters such as lakes, rivers and reservoirs. We report herein a new architectu...Nitrate is the leading cause of eutrophication worldwide and is one of the most challenging pollutants for restoration of polluted surface waters such as lakes, rivers and reservoirs. We report herein a new architecture of iron nanoparticles for high-efficiency denitrification by selective reduction of nitrate (NO3-) to dinitrogen (N2). The iron nanoparticles are doped with nitrogen (FeN) and encapsulated within a thin layer of nitride-carbon (NC). The nanoparticles have high pyrrolic N content (17.4 at.%) and large specific surface area (2040 m2/g). Laboratory experiments demonstrated high N2selectivity (91%) and nitrate removal capacity (6004 mg N/g Fe) for treatment of nitrate-containing water. This iron-based nanomaterial overcomes shortcomings of conventional catalysts by eliminating the use of precious and toxic heavy metals (e.g., Pd, Pt, Cu, Ni) and minimizing the generation of undesirable byproducts (e.g., ammonia) from the reactions with nanoscale zero-valent iron (n ZVI). The multiple electron transfers process from NO3- to N2can be fine-tuned by adjusting the NC shell thickness. Superior electrocatalytic perfor- mance, low cost and minimal environmental impact of the iron-derived nanocatalyst offer promising prospects for water purification, waste treatment and environmental remediation.展开更多
Sediment-water interfaces are important interfaces for lakes,which are related to most environmental and ecological problems.Wind-induced waves cause secondary pollution via sediment resuspension.Since the coupling me...Sediment-water interfaces are important interfaces for lakes,which are related to most environmental and ecological problems.Wind-induced waves cause secondary pollution via sediment resuspension.Since the coupling mechanism of water,resuspended sediments,and phosphorus affects the release of phosphorus(P)near the interface,a coupled model was explored for two sediment types with different adsorption-desorption capabilities to examine sediment resuspension and P release.The relationships among wind speed,wave characteristics,sediment distribution and P concentration were obtained.For different sediments,the unit sediment desorption release is negatively correlated with wind speed.When sediments are resuspended under low or moderate wind speed,the P concentration in the overlying water increases abruptly,hampering diffusion.P release exhibits the characteristics of concentrated release in a small region and changes the water environment rapidly.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 41005078 and 41175127)
文摘Abstract Chinese air pollution has increased in this century along with the rapid socioeconomic development and resulting anthropogenic emissions. While recent emission control measures have shown encouraging re sults and have reduced the levels of sulfur dioxide and primary aerosols, the concentrations of other air pollutants continue to grow, particularly secondary pollutants in cluding ozone and secondary aerosols. Meanwhile, a va riety of intentional and unintentional socioeconomic events have temporarily changed the pace, and even the signs, of growth of air pollution. These events include the short-term emission restrictions imposed during the Sino-African Summit, the Beijing Olympics and Para lympics, the Shanghai World Exposition （Shanghai Expo）, the Guangzhou Asian Olympics, and the Shenzhen Uni versiade, as well as the unintentional emission reductions associated with the recent economic recession and the annual Chinese New Year. This paper presents a brief overview of trends and temporary perturbations of Chi nese air pollution since 2000, summarizing studies on anthropogenic emission inventories, atmospheric meas urements, and inverse modeling. It concludes with rec ommendations for future research.
基金This work was financially supported by the National Natural Science Foundation of China(51978488,41772243 and 41673096).
文摘Nitrate is the leading cause of eutrophication worldwide and is one of the most challenging pollutants for restoration of polluted surface waters such as lakes, rivers and reservoirs. We report herein a new architecture of iron nanoparticles for high-efficiency denitrification by selective reduction of nitrate (NO3-) to dinitrogen (N2). The iron nanoparticles are doped with nitrogen (FeN) and encapsulated within a thin layer of nitride-carbon (NC). The nanoparticles have high pyrrolic N content (17.4 at.%) and large specific surface area (2040 m2/g). Laboratory experiments demonstrated high N2selectivity (91%) and nitrate removal capacity (6004 mg N/g Fe) for treatment of nitrate-containing water. This iron-based nanomaterial overcomes shortcomings of conventional catalysts by eliminating the use of precious and toxic heavy metals (e.g., Pd, Pt, Cu, Ni) and minimizing the generation of undesirable byproducts (e.g., ammonia) from the reactions with nanoscale zero-valent iron (n ZVI). The multiple electron transfers process from NO3- to N2can be fine-tuned by adjusting the NC shell thickness. Superior electrocatalytic perfor- mance, low cost and minimal environmental impact of the iron-derived nanocatalyst offer promising prospects for water purification, waste treatment and environmental remediation.
基金supported by the Strategic Priority Research Program of the National Key R&D Program of China(Grant Nos.201BYf,CJ505500,and 201BYFCI505504)the National Natural Science Foundation of China(NSFC)(Grant Nos.11802313,and 12032005).
文摘Sediment-water interfaces are important interfaces for lakes,which are related to most environmental and ecological problems.Wind-induced waves cause secondary pollution via sediment resuspension.Since the coupling mechanism of water,resuspended sediments,and phosphorus affects the release of phosphorus(P)near the interface,a coupled model was explored for two sediment types with different adsorption-desorption capabilities to examine sediment resuspension and P release.The relationships among wind speed,wave characteristics,sediment distribution and P concentration were obtained.For different sediments,the unit sediment desorption release is negatively correlated with wind speed.When sediments are resuspended under low or moderate wind speed,the P concentration in the overlying water increases abruptly,hampering diffusion.P release exhibits the characteristics of concentrated release in a small region and changes the water environment rapidly.
