Metallic Iron for Water Remediation: Plenty of Room for Collaboration and Convergence to Advance the Science

Scientific collaboration among various geographically scattered research groups on the broad topic of "metallic iron (Fe-0) for water remediation" has evolved greatly over the past three decades. This collaboration has involved different kinds of research partners, including researchers from the same organization and domestic researchers from non-academic organizations as well as international partners. The present analysis of recent publications by some leading scientists shows that after a decade of frank collaboration in search of ways to improve the efficiency of Fe-0/H2O systems, the research community has divided itself into two schools of thought since about 2007. Since then, progress in knowledge has stagnated. The first school maintains that Fe-0 is a reducing agent for some relevant contaminants. The second school argues that Fe-0 in-situ generates flocculants (iron hydroxides) for contaminant scavenging and reducing species (e.g., Fe-II, H-2, and Fe3O4), but reductive transformation is not a relevant contaminant removal mechanism. The problem encountered in assessing the validity of the views of both schools arises from the quantitative dominance of the supporters of the first school, who mostly ignore the second school in their presentations. The net result is that the various derivations of the original Fe-0 remediation technology may be collectively flawed by the same mistake. While recognizing that the whole research community strives for the success of a very promising but unestablished technology, annual review articles are suggested as an ingredient for successful collaboration.