成人做爰免费视频免费看_成人a级高清视频在线观看,成人a大片在线观看,成人a大片高清在线观看,成人av在线播放,一a一级片,一级黄 中国色 片,一级黄 色蝶 片,一级黄色 片生活片

 文獻名： Transport and retention of silver nanoparticles in soil: Effects of input concentration, particle size and surface coating

 

作者： Jianzhou He^a,b; Dengjun Wang^c; Dongmei Zhou^a

^aKey Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China

^bUniversity of Chinese Academy of Sciences, Beijing 100049, China

^cNational Research Council Resident Research Associate, U.S. Environmental Protection Agency, Ada, OK 74820, United States

 

摘要：Soils are considered as a major sink for engineered nanoparticles (ENPs) because of their inevitable release to the subsurface environment during production, transportation, use and disposal processes. In this context, the transport and retention of silver nanoparticles (AgNPs) with different input particle concentration, particle size, and surface coating were investigated in clay loam using water-saturated column experiments. Our results showed that the mobility of AgNPs in the soil was considerably low, and >73.9% of total injected AgNPs (except for no coating condition) was retained in columns. This is primarily due to the high specific surface area and favorable retention sites in soil. Increased transport of AgNPs occurred at higher input concentration and smaller particle size. The presence of surface coatings (i.e., polyvinylpyrrolidone (PVP) and citrate) further promoted the transport and reduced the retention of AgNPs in soil, which is likely due to their effective blocking of the solid-phase sites that are originally available for AgNPs retention. Although the shape of retention profiles (RPs) of AgNPs was either hyperexponential or nonmonotonic that is different from the colloid filtration theory prediction, the 1-species (consider both time- and depth-dependent retention) and/or 2-species (account for the release of reversibly deposited AgNPs) model successfully described the transport behaviors of AgNPs in soil columns under all the investigated conditions. This study proves the applicability of mathematical model in predicting the fate and transport of ENPs in real soils, and our findings presented herein are significant to ultimately develop management strategies for reducing the potential risks of groundwater contamination due to ENPs entering the environment.