Influence of water chemistry on the environmental behaviors of commercial ZnO nanoparticles in various water and wastewater samples
Journal
Journal of Hazardous Materials
Journal Volume
322
Journal Volume
322
Pages
348-356
Start Page
348
End Page
356
ISSN
03043894
Date Issued
2017-01-15
Author(s)
Abstract
Zinc oxide nanoparticles (ZnO NPs) are widely used nanomaterials and their environmental impacts have received increasing attention. The fate and toxicity of ZnO NPs in the environment are determined by their stability and dissolution. In this study, the influence of water chemistry on aggregation, sedimentation, and dissolution of ZnO NPs was investigated. The stabilized ZnO NPs aggregated and precipitated when the aqueous pH closed to their zero point of charge (pHzpc). Counter-ions neutralized the surface charge of NPs and promoted their destabilization. However, a high concentration of counter-ion (SO4 2−, >10 meq/L) made the NPs more stable because of the inverted surface potential. The stability of ZnO NPs was maintained by high concentration of Suwannee River humic acid (SRHA, 10 mg/L) even the concentration of electrolytes was high. The influence of water chemistry on the stability and dissolution of ZnO NPs was further demonstrated in different wastewaters. In one wastewater sample, ZnO NPs was unexpectedly stable and with a high dissolution, which was due to the effects of pH value, organic matter concentration, as well as the concentration of counter ions. Our findings facilitate the predictions of the fate of stabilized ZnO NPs in the environment.
Subjects
Aggregation
Dissolution
Sedimentation
Wastewater
Zinc oxide nanoparticle
Publisher
Elsevier B.V.
Type
journal article