fulltext.pdf 995 KB
Kamba, Yuya Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University
Ueta, Miharu Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University
Uddin, Md. Azhar Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University
Zinc (Zn) removal by physically mixed particles of zero-valent iron (Fe) and iron sulfide (FeS) was investigated as one technology for Zn removal from waste groundwater. The effects of the Fe/FeS mass ratio, including a single Fe and FeS particles, and pH on changes in the concentrations of Zn, Fe, and S were examined by a batch test and column tests, and the mechanism of Zn elimination was discussed. Among all the mixing fractions of Fe and FeS, Zn was eliminated most effectively by 3Fe/7FeS (mass ratio of Fe/FeS = 3/7). The Zn removal rate decreased in the order of 3Fe/7FeS, FeS, and Fe, whereas the Fe concentration decreased in the order of Fe, FeS, and 3Fe/7FeS. The S concentration of FeS was larger than that of 3Fe/7FeS. The Zn removal rate by physically mixed 3Fe/7FeS particles was enhanced by a local cell reaction between the Fe and FeS particles. The electrons caused by Fe corrosion moved to the FeS surface and reduced the dissolved oxygen in the solution. Zn2+, Fe2+, and OH− ions in the solution were then coprecipitated on the particles as ZnFe2(OH)6 and oxidized to ZnFe2O4. Moreover, Zn2+ was sulfurized as ZnS by both the Fe/FeS mixture and the simple FeS particles. The Zn removal rate increased with increasing pH in the range from pH 3 to 7. From a kinetic analysis of Zn removal, the rate constant of anode (Fe)/cathode (FeS) reaction was almost the same as that of ZnS formation and slightly larger than that of Fe alone.
This is a post-peer-review, pre-copyedit version of an article published in Water, Air, & Soil Pollution. The final authenticated version is available online at: http://dx.doi.org/10.1007/s11270-020-04966-4.
Water, Air, & Soil Pollution
|Web of Science KeyUT|