The clincher: According to the journal, the researchers did not possess the proper lab equipment to perform the study as reported.
The article, “Detoxification of high-strength liquid pollutants in an ozone bubble column reactor: Gas–liquid flow patterns, interphase mass transfer and chemical depuration,” appeared in August 2011 and was written by Rodrigo J. G. Lopes and Rosa M. Quinta-Ferreira, from the Group on Environmental, Reaction and Separation Engineering in the Department of Chemical Engineering at the University of Coimbra. The paper has been cited twice, according to Thomson Scientific’s Web of Knowledge, both times by the original authors.
Here’s what the abstract has to say about the work:
The contemporary status of computational flow modelling is encouraging the application of modern CFD codes to the design and investigation of multiphase reactors. Aiming to accomplish novel and stringent environmental regulations on the decontamination of high-strength wastewaters, here we present a comprehensive discrete bubble model for the ozonation of liquid pollutants. As long as a bubble column reactor can operate on a multitude of hydrodynamic regimes, first we developed an Euler-Lagrange CFD model coupling the transport processes such as momentum and mass transfer, and ozonation kinetics. The model has been reasonably accounted for the dependency of flow regimes and extent of interaction among gas and liquid phases. Second, a quantitative assessment between computed and experimental gas and liquid superficial velocities indicated that ozone velocity and concentration play a prominent role on the mineralization rate. We found that the process efficiency has been increased until it reveals a quasi-steady behavior which indicated that the reaction system happens to be noticeably reliant on oxidant concentrations under bubbly flow conditions. Finally, interstitial flow maps were effectively corroborated with total organic carbon concentration profiles as function of inlet bubble velocities and ozone concentrations.
But according to the retraction notice, interstitial flow maps were not effectively corroborated with total organic carbon concentration profiles, for the simple reason that the researchers had no way of finding that out:
This article has been retracted at the request of the Editors for unethical use of data reporting. The article reports data that could not be obtained in the laboratory as the necessary equipment was not present.
We’re reading between the lines here, but it seems the first author, Lopes, is the key. Earlier this year, Chemical Engineering Research and Design retracted a 2012 paper on which he was corresponding author, “Multiphase CFD simulations of catalytic wet oxidation of phenol-like compounds in high-pressure trickle-bed reactors: Reactive flow and temperature behaviour,” because Lopes had forged the names of his coauthors:
The corresponding author did not gain permission from the co-authors to add their names to this paper prior to submission.
That paper — which cites the newly retracted Chemical Engineering Journal study — has yet to be cited.
Quinta-Ferreira was among the researchers listed on the article. She also appears on a 2011 article, with Lopes as first and corresponding author, in the Journal of Hazardous Materials. That paper, “Integrated detoxification methodology of hazardous phenolic wastewaters in environmentally based trickle-bed reactors: Experimental investigation and CFD simulation,” has not been retracted.
Word to the wise for the JHM: It might be time to look closely at that paper, if you haven’t already.