Comments on “Reply to Comments on Comparison of reductive dechlorination of p-chlorophenol using Fe0 and nanosized Fe0”, by Wang & Cheng, Journal of Hazardous Materials (2007), In Press

It is unclear as to whether Wang & Cheng’s reply [1] actually addresses the specific criticisms made in the comments [2] on their article [3]. Although the authors said that they do agree with enumerated viewpoints, their reply seems to be limited at justifying their experimental conditions: the used mixing intensity and iron (Fe0) loading. The comments [2] should have certainly more carefully considered the R-values in relation with the specific objective of the individual experiments. Nevertheless, it should be pointed out that even though the actual reaction stoichiometry may be difficult to access, an adequate assumption can be made. For example by considering Fe0 as the sole contaminant reducing agent and balancing the redox equation for complete contaminant reduction. Another remark concerns the fact that procedures that are currently/usually used are not always practical. This is true in particular for using the same mass of Fe0 in excess and for mixing the reacting systems. It is the challenge of scientific research to identify disturbing factors and eliminate them for better process understanding. Considering the effect of mixing operations it is clear that any mixing intensity above natural turbulence is too vigorous. Mixing disturbs processes of oxide-film formation [4], might kee