暴露于空气中的金属受环境影响,表面会产生吸附、沾污和氧化等表面改性作用,引起二次电子产额(secondary electron yield,SEY)变化。为探究银表面改性对SEY的影响,使用加热、有机清洗、离子清洗实现了多种银表面状态。实验结果显示,加...暴露于空气中的金属受环境影响,表面会产生吸附、沾污和氧化等表面改性作用,引起二次电子产额(secondary electron yield,SEY)变化。为探究银表面改性对SEY的影响,使用加热、有机清洗、离子清洗实现了多种银表面状态。实验结果显示,加热能够去除部分表面吸附和沾污,并使得SEY降低;离子清洗在去除表面吸附和沾污的同时还能够剥离表面氧化层,获得高度洁净的表面。离子清洗10/30分钟后SEY峰值由2.61降至1.73/1.70,说明剥离银表面的吸附、沾污和氧化层能使得SEY明显降低。为验证氧化对SEY的影响,使用磁控溅射制备氧化银薄膜。结果表明,氧化银SEY仅比银高0.1左右,且在斜入射下两者SEY差异更小,该结果证明银表面发生氧化不会使得SEY明显升高,并间接说明表面吸附和沾污是使得银表面SEY升高的主要因素。展开更多
The efficient and rapid separation of oil from stabilized oil-in-water emulsions with micro/nanometer size is a global challenge.Owing to the low oil content in oil-in-water emulsions,separating the oil by simply cont...The efficient and rapid separation of oil from stabilized oil-in-water emulsions with micro/nanometer size is a global challenge.Owing to the low oil content in oil-in-water emulsions,separating the oil by simply controlling the surface wettability is difficult.Controlling the pore size of the membrane surface to achieve separation will lead to a sharp decrease in flux.Herein,inspired by cell membrane transportation,a hydrophilic/hydrophobic bifunctional Janus membrane for stable oil-in-water separation was prepared by simple surface polymerization and vapor diffusion.The prepared Janus membrane contained a hydrophobic side and hydrophilic polyamine layer.When used for oil-in-water emulsion separation,the polyamine layer accumulated micro/nanometer oil droplets,forming an oil layer on the hydrophobic surface.Water was retained by the 1H,1H,2H,2H-perfluorooctyl trichlorosilane layer,allowing oil droplets to selectively permeate through the membrane,achieving the separation effect.As the pore size of the modified fabric was basically unchanged,the permeation flux was fast(1.53×10^(3) Lm^(−2) h^(−1)).Furthermore,the poly(N,N-dimethylaminoethyl methacrylate)layer destroyed the emulsion stability,making the emulsion droplets aggregate without affecting the separation efficiency with fast permeation flux.Therefore,the prepared bifunctional Janus membrane shows great potential for actual wastewater treatment.展开更多
文摘暴露于空气中的金属受环境影响,表面会产生吸附、沾污和氧化等表面改性作用,引起二次电子产额(secondary electron yield,SEY)变化。为探究银表面改性对SEY的影响,使用加热、有机清洗、离子清洗实现了多种银表面状态。实验结果显示,加热能够去除部分表面吸附和沾污,并使得SEY降低;离子清洗在去除表面吸附和沾污的同时还能够剥离表面氧化层,获得高度洁净的表面。离子清洗10/30分钟后SEY峰值由2.61降至1.73/1.70,说明剥离银表面的吸附、沾污和氧化层能使得SEY明显降低。为验证氧化对SEY的影响,使用磁控溅射制备氧化银薄膜。结果表明,氧化银SEY仅比银高0.1左右,且在斜入射下两者SEY差异更小,该结果证明银表面发生氧化不会使得SEY明显升高,并间接说明表面吸附和沾污是使得银表面SEY升高的主要因素。
基金supported by the National Key Research and Development Program of China(Grant No.2020YFC1808401)the National Natural Science Foundation of China(Grant Nos.22078213,21938006,51973148,21776190)+1 种基金the Cutting-edge Technology Basic Research Project of Jiangsu(Grant No.BK20202012)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The efficient and rapid separation of oil from stabilized oil-in-water emulsions with micro/nanometer size is a global challenge.Owing to the low oil content in oil-in-water emulsions,separating the oil by simply controlling the surface wettability is difficult.Controlling the pore size of the membrane surface to achieve separation will lead to a sharp decrease in flux.Herein,inspired by cell membrane transportation,a hydrophilic/hydrophobic bifunctional Janus membrane for stable oil-in-water separation was prepared by simple surface polymerization and vapor diffusion.The prepared Janus membrane contained a hydrophobic side and hydrophilic polyamine layer.When used for oil-in-water emulsion separation,the polyamine layer accumulated micro/nanometer oil droplets,forming an oil layer on the hydrophobic surface.Water was retained by the 1H,1H,2H,2H-perfluorooctyl trichlorosilane layer,allowing oil droplets to selectively permeate through the membrane,achieving the separation effect.As the pore size of the modified fabric was basically unchanged,the permeation flux was fast(1.53×10^(3) Lm^(−2) h^(−1)).Furthermore,the poly(N,N-dimethylaminoethyl methacrylate)layer destroyed the emulsion stability,making the emulsion droplets aggregate without affecting the separation efficiency with fast permeation flux.Therefore,the prepared bifunctional Janus membrane shows great potential for actual wastewater treatment.
