Micro-nanobubbles as interface regulators to enhance electron transfer on mackinawite for promoting natural attenuation

Huang X 1 , Dai C 2 , Li J 3 , Liu Q 4 , Zhou H 4 , Leong KH 5 Show all authors , Yeap SP 6 , You X 7 , Zhang Y 8

Affiliations 

  • 1 Department of Geological and Hydraulic Engineering, College of Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Department of Environmental Science and Engineering, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
  • 2 Department of Geological and Hydraulic Engineering, College of Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China. Electronic address: daichaomeng@tongji.edu.cn
  • 3 Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 200120, China. Electronic address: lijixiang@sari.ac.cn
  • 4 Department of Environmental Science and Engineering, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
  • 5 Environmental Engineering Laboratory, Department of Civil Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
  • 6 Department of Chemical and Petroleum Engineering, Faculty of Engineering, Technology & Built Environment, UCSI University, Cheras, Kuala Lumpur 56000, Malaysia
  • 7 Department of Environmental Science and Engineering, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China. Electronic address: xjyou@shu.edu.cn
  • 8 State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China
J Hazard Mater, 2026 Oct 01;517:143835.
PMID: 42849070 DOI: 10.1016/j.jhazmat.2026.143835

Abstract

Naphthalene (NAP), a representative polycyclic aromatic hydrocarbon (PAH), is a hazardous groundwater contaminant because of its persistence, toxicity, and potential carcinogenicity. Although naturally occurring mackinawite (FeS) contributes to pollutant attenuation through reactive oxygen species (ROS) generation during oxygen perturbation, its reactivity is limited by inefficient interfacial electron transfer. Here, micro-nanobubbles (MNBs) were introduced as a chemical-free interfacial regulation strategy to activate FeS, significantly enhancing hydroxyl radical (•OH) production and NAP degradation. Results revealed that the strong interfacial electric field of MNBs could regulate the FeS interface and generate Fe(II) active sites, leading to approximately 7.4-fold and 1.5-fold increases in the electron utilization efficiency of ion-exchangeable and structural Fe(II), respectively. Meanwhile, MNBs accelerated the initial oxidation of S(-II) in the early reaction stage, thereby preventing prolonged competition with Fe(II) for O2 and ultimately improving Fe(II) utilization efficiency and •OH production. Furthermore, DFT calculations and ECOSAR toxicity predictions indicated that the MNB-mediated pathway drove NAP toward more reactive intermediates, reducing the risk of toxicity amplification and enhancing mineralization. Overall, this study demonstrates that MNBs effectively unlock the natural attenuation potential of FeS, providing a clean and sustainable strategy for in-situ groundwater remediation.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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