An overview of preparation and applications of stabilized zero-valent iron nanoparticles for soil and groundwater remediation

• Published in: Water research (Oxford) Vol. 100; pp. 245 - 266
• Main Authors: Zhao, Xiao, Liu, Wen, Cai, Zhengqing, Han, Bing, Qian, Tianwei, Zhao, Dongye
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-09-2016
• Subjects: Dechlorination; Environmental Restoration and Remediation; Groundwater; Iron; Metal Nanoparticles; Soil; Soil remediation; Stabilized nanoparticles; Water contamination; Zero-valent iron; Stabilized nanoparticles; Soil remediation; Dechlorination; Groundwater; Zero-valent iron; Water contamination
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2016.05.019

Nano-scale zero-valent iron (nZVI) is one of the most intensively studied materials for environmental cleanup uses over the past 20 years or so. Freshly prepared nZVI is highly reactive due to its high specific surface area and strong reducing power. Over years, the classic borohydride reduction method for preparing nZVI has been modified by use of various stabilizers or surface modifiers to acquire more stable and soil deliverable nZVI for treatment of different organic and inorganic contaminants in water and soil. While most studies have been focused on testing nZVI for water treatment, the greater potential or advantage of nZVI appears to be for in situ remediation of contaminated soil and groundwater by directly delivering stabilized nZVI into the contaminated subsurface as it was proposed from the beginning. Compared to conventional remediation practices, the in situ remediation technique using stabilized nZVI offers some unique advantages. This work provides an update on the latest development of stabilized nZVI for various environmental cleanup uses, and overviews the evolution and environmental applications of stabilized nZVI. Commonly used stabilizers are compared and the stabilizing mechanisms are discussed. The effectiveness and constraints of the nZVI-based in situ remediation technology are summarized. This review also reveals some critical knowledge gaps and research needs, such as interactions between delivered nZVI and the local biogeochemical conditions.
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•Critically reviewed applications of stabilized ZVI nanoparticles in last 20 years.•Compared effectiveness of various stabilizers and elucidated stabilizing mechanism.•Identified critical knowledge gaps and constraints of ZVI-based cleanup technology.•Stabilizers enhance soil deliverability and reactivity of nZVI for in situ remediation.•Stabilized ZVI nanoparticles do not pose significant adverse effects on biota.