Fate of lead-zinc reaction products with different types of nZVI during aging in simulated groundwater and heavy metal release under dynamic environmental conditions

Area of Science:

• Environmental Science
• Materials Science
• Geochemistry

Background:

• Nanoscale zerovalent iron (nZVI) is crucial for remediating heavy metal-contaminated groundwater.
• Understanding the long-term transformation of nZVI-heavy metal (nZVI-HM) reaction products and metal dynamics is essential.

Purpose of the Study:

• Investigate the long-term transformation of nZVI, sulfurized nZVI (S-nZVI), and carboxymethyl cellulose (CMC) modified nZVI.
• Assess the potential for heavy metal release from these materials under varying environmental conditions.

Main Methods:

• Studied the remediation of lead (Pb) and zinc (Zn) contaminated groundwater over two months.
• Analyzed the structural evolution and composition of nZVI-HM hybrids.
• Evaluated the influence of groundwater constituents, reaction time, and nanomaterial type on remediation.

Main Results:

• All tested nZVI materials showed excellent heavy metal removal across diverse aquatic environments.
• Groundwater constituents and reaction duration influenced nZVI-HM hybrid structures.
• Humic acid had minimal impact, but pH fluctuations affected Pb/Zn sequestration, with Zn2+ release at low pH.
• Modified nZVI, especially S-nZVI, showed better acid tolerance; prolonged aging stabilized dissolved Zn2+.

Conclusions:

• nZVI nanomaterials are effective for long-term groundwater remediation.
• Modified nZVI materials offer improved stability and reduced risk of heavy metal release.
• Findings provide a scientific basis for evaluating nZVI efficacy and environmental risks in groundwater remediation.