Influence of water chemistry on the environmental behaviors of commercial ZnO nanoparticles in various water and wastewater samples

Yu-Huei Peng; Yi-Chun Tsai; Chia-En Hsiung; Yi-Hsuan Lin; Yang-Hsin Shih

doi:10.1016/j.jhazmat.2016.10.003

Influence of water chemistry on the environmental behaviors of commercial ZnO nanoparticles in various water and wastewater samples

J Hazard Mater. 2017 Jan 15;322(Pt B):348-356. doi: 10.1016/j.jhazmat.2016.10.003. Epub 2016 Oct 15.

Authors

Yu-Huei Peng¹, Yi-Chun Tsai¹, Chia-En Hsiung¹, Yi-Hsuan Lin¹, Yang-Hsin Shih²

Affiliations

¹ Department of Agricultural Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan, ROC.
² Department of Agricultural Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan, ROC. Electronic address: yhs@ntu.edu.tw.

PMID: 27773444
DOI: 10.1016/j.jhazmat.2016.10.003

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 (pH_zpc). Counter-ions neutralized the surface charge of NPs and promoted their destabilization. However, a high concentration of counter-ion (SO₄^2-, >10meq/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, 10mg/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.

Keywords: Aggregation; Dissolution; Sedimentation; Wastewater; Zinc oxide nanoparticle.