This cluster of papers focuses on the applications and remediation potential of nanoscale zero-valent iron (nZVI) in groundwater remediation, wastewater treatment, and environmental cleanup. The papers cover topics such as heavy metal removal, contaminant sequestration, reductive dechlorination, and the use of permeable reactive barriers. They also explore surface modifications, spectroscopic investigation, and the long-term performance of nZVI in various environmental conditions.