Comments on: “The effect of substituent groups on the reductive degradation of azo dyes by zerovalent iron.” By Hou M. et al. [J. Hazard. Mater. 145 (2007) 305]

This letter discusses possible improvements in experimental conditions to enable a purposeful discussion on the effect of substituent groups on the reductive degradation of azo dyes by elemental iron (Fe0) in a recent article by M. Hou and his co-workers. Also recalled is the pH dependence of the iron corrosion mechanism which is usually overlooked in the iron technology literature