Discharge inventory of pharmaceuticals and personal care products in Beijing,China

Pharmaceuticals and personal care products(PPCPs)are emerging environmental contaminants,whose potential risk for the ecological environment has caused wide attention in recent years.In China,quite a large amount of PPCPs were annually emitted into the environment.Their existence in different matrix has been reported frequently,including river water,sediment and soil.However,the contribution from different sources was seldom reported and still unclear in China.Wastewater treatment plant(WWTP)was usually considered to be the main source to the urban river,but livestock and aquaculture farms were also reported as significant pollution sources of PPCPs due to poor environmental management in China.This study summarized environmental discharges of different PPCPs from various sources and obtained the discharge data through different environment media in Beijing,the statistical source of PPCPs was analyzed in detail.The sources comprised WWTPs,excess sludge,hospital wastewater,municipal untreated wastewater,aquaculture wastewater and landfill leachate.This article helps understand the general situation and the potential risk of PPCPs in Beijing.

Correlating the fluctuated growth of carbon nanotubes with catalyst evolution by atmospheric-pressure environmental transmission electron microscopy

Rate-controlled growth of carbon nanotubes(CNTs)and catalyst design are considered efficient ways for the preparation of CNTs with specific structures and properties.However,due to the difficulties in capturing the growth process of the CNTs with tiny size under a complex growth environment,the growth kinetics of CNTs and their correlation with the catalyst seed have been seldom revealed.Here,we investigated the growth process of CNTs from Ni nanoparticles(NPs)in real-time under atmospheric pressure using transmission electron microscopy equipped with a closed gas cell.It was found that the growth rates of CNTs fluctuated,and a phase transition from Ni_(3)C to Ni,and a reshaping of the catalyst NPs occurred during the growth process.We demonstrated that CNTs dynamically interacted with the connected catalyst NPs and the fluctuated growth rates of CNTs were correlated with the structure change of catalyst NPs.The origin of the growth rate fluctuation is attributed to the change of carbon concentration gradient in catalyst NPs.