title: Degradation products from consumer nanocomposites: a case study on quantum dot lighting.
abstract: Most nanomaterials enter the natural environment as nanoenabled products, which are typically composites with primary nanoparticles bound on substrates or embedded in liquid or solid matrices. The environmental risks associated with these products are expected to differ from those associated with the as-produced particles. This article presents a case study on the end-of-life emission of a commercial prototype polymer/quantum-dot (QD) composite used in solid-state lighting for homes. We report the extent of cadmium release upon exposure to a series of environmental and biological simulant fluids, and track the loss of QD-characteristic fluorescence as a marker for chemical damage to the CdSe/ZnS nanoparticles. Measured cadmium releases after 30-day exposure range from 0.007 to 1.2 mg/g of polymer, and the higher values arise for low-pH simulants containing nitric or gastric acid. Centrifugal ultrafiltration and ICP was used to distinguish soluble cadmium from particulate forms. The leachate is found to contain soluble metals with no evidence of free QDs or QD-containing polymeric debris. The absence of free nanoparticles suggests that this product does not raise nanotechnology-specific environmental issues associated with degradation and leaching, but is more usefully regarded as a conventional chemical product that is a potential source of small amounts of soluble cadmium.
authors.affiliation: Department of Chemistry, Brown University, Providence, Rhode Island, United States.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Liu
authors.forename: John
authors.initials: J
authors.lastname: Katahara
authors.forename: Guanglai
authors.initials: G
authors.lastname: Li
authors.forename: Seth
authors.initials: S
authors.lastname: Coe-Sullivan
authors.forename: Robert H
authors.initials: RH
authors.lastname: Hurt
mesh_terms: D001578:Benzopyrans / Q000737:chemistry; D002104:Cadmium / Q000032:analysis*; D019187:Cadmium Compounds / Q000737:chemistry*; D003257:Consumer Product Safety; D005744:Gastric Acid / Q000737:chemistry; D006812:Humic Substances; D006861:Hydrogen Peroxide / Q000737:chemistry; D008029:Lighting; D008856:Microscopy, Fluorescence; D053761:Nanocomposites / Q000737:chemistry*; D017942:Nitric Acid / Q000737:chemistry; D016877:Oxidants / Q000737:chemistry; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D001578:Benzopyrans; D019187:Cadmium Compounds; D006812:Humic Substances; D016877:Oxidants; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D002104:Cadmium; D014867:Water; D017942:Nitric Acid; D012965:Sodium Chloride; C058667:cadmium selenide; D006861:Hydrogen Peroxide; C031238:zinc sulfide; C005023:fulvic acid