A comparative study on aggregation and sedimentation of natural goethite and artificial Fe3O4 nanoparticles in synthetic and natural waters based on extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory and molecular dynamics simulations

Aiming Wu; Xiaoli Zhao; Chunyan Yang; Junyu Wang; Xia Wang; Weigang Liang; Lingfeng Zhou; Miaomiao Teng; Lin Niu; Zhi Tang; Guoqing Hou; Fengchang Wu

doi:10.1016/j.jhazmat.2022.128876

A comparative study on aggregation and sedimentation of natural goethite and artificial Fe₃O₄ nanoparticles in synthetic and natural waters based on extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory and molecular dynamics simulations

J Hazard Mater. 2022 Aug 5:435:128876. doi: 10.1016/j.jhazmat.2022.128876. Epub 2022 Apr 7.

Authors

Aiming Wu¹, Xiaoli Zhao², Chunyan Yang³, Junyu Wang⁴, Xia Wang⁴, Weigang Liang⁴, Lingfeng Zhou⁴, Miaomiao Teng⁴, Lin Niu⁴, Zhi Tang⁴, Guoqing Hou⁴, Fengchang Wu¹

Affiliations

¹ College of Environment, Hohai University, Nanjing 210098, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
² State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: zhaoxiaoli_zxl@126.com.
³ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environment Protection Key Laboratory of Regional Eco-Process and Function Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
⁴ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.

PMID: 35468390
DOI: 10.1016/j.jhazmat.2022.128876

Abstract

Natural iron oxides nanomaterials have important roles in biogeochemical processes. In this study, the effects of pH, natural organic matter, and cations on aggregation and sedimentation of natural goethite and artificial Fe₃O₄ nanoparticles in water were investigated to learn more about the environmental behaviors of engineered and natural nanomaterials and how they differ. In addition, a novel extended DLVO theory that considered steric, gravitational, and magnetic attraction forces concurrently was specifically developed to provide mechanisms explanations. Specifically, Fe₃O₄ NPs were more likely than bulk goethite to aggregate (because of magnetic attraction interactions) at low HA concentrations and disperse at high HA concentrations. Besides, goethite was less prone to settle with the same concentration of NaCl than Fe₃O₄ NPs, but the opposite trend was found for the same concentration of CaCl₂ because of the difference in maximum net energy (barrier) and strong Ca²⁺ bridging effectiveness of goethite in CaCl₂ solution. Statistical models were established to evaluate colloidal stability of the particles. XPS and molecular dynamics simulation results suggested that ions were adsorbed onto particles via ionic polarization and that the binding free energies at high coverage followed the order Ca²⁺ > Na⁺ > Cl^- and presence of cation bridging between particles.

Keywords: Aggregation; Cation bridging; Extended Derjaguin−Landau−Verwey−Overbeek (XDLVO); Iron oxides nanomaterials; Molecular dynamics (MD) simulation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Calcium Chloride
Cations
Iron Compounds
Minerals
Molecular Dynamics Simulation*
Nanoparticles*

Substances

Cations
Iron Compounds
Minerals
goethite
Calcium Chloride