Water chemistry influences on long-term dissolution kinetics of CdSe/ZnS quantum dots  

作　　者：Pooya Paydary Philip Larese-Casanova 

机构地区：[1]Department of Civil and Environmental Engineering,Northeastern University,Boston,MA,USA

出　　处：《Journal of Environmental Sciences》2020年第4期216-233,共18页环境科学学报（英文版）

基　　金：financially supported by the United States National Science Foundation(grant number CBET-1254245)

摘　　要：Widespread usage of engineered metallic quantum dots(QDs)within consumer products has evoked a need to assess their fate within environmental systems.QDs are mixed-metal nanocrystals that often include Cd2+which poses a health risk as a nanocrystal or when leached into water.The goal of this work is to study the long-term metal cation leaching behavior and the factors affecting the dissolution processes of mercaptopropionic acid(MPA)capped CdSe/ZnS QDs in aphotic conditions.QD suspensions were prepared in different water conditions,and release of Zn2+and Cd2+cations were monitored over time by size exclusion chromatography-inductively coupled plasm a-mass spectrometry.In most conditions with dissolved 02 present,the ZnS shell degraded fairly rapidly over^1 week,while some of the CdSe core remained up to 80 days.Additional MPA,Zn2+,and Cd2+temporarily delayed dissolution,indicating a moderate role for capping agent detachment and mineral solubility.The presence of H2 O2 and the ligand ethylenediaminetetraacetate accelerated dissolution,while NOM had no kinetic effect.No dissolution of CdSe core was observed when 02 was absent or when QDs formed aggregates at higher concentrations with 02 present.The shrinking particle model with product layer diffusion control best describes Zn2+and Cd2+dissolution kinetics.The longevity of QDs in their nanocrystal form appears to be partly controlled by environmental conditions,with anoxic,aphotic environments preserving the core mineral phase,and oxidants or complexing ligands promoting shell and core mineral dissolution.

关 键 词：Quantum dots CDSE/ZNS Dissolution kinetics Shrinking particle model Size exclusion chromatography Inductively coupled plasma mass spectrometry 

分 类 号：X832[环境科学与工程—环境工程]