2018 Volume 41 Issue 4 Pages 73-81
Soil contamination and accompanying groundwater contamination by heavy metals is a serious environmental problem worldwide. In this study, sorption properties of lead and cadmium onto kaolinite under the presence and absence of hydroxamate siderophore (desferrioxamine B, DFOB) were investigated. The obtained insights were then used to interpret the results obtained from the experiments performed to investigate the influence of DFOB on the immobilization performance of lead and cadmium in kaolinite using magnesium oxide (MgO) . The experimental results and species calculation showed that DFOB influenced the sorption properties of these heavy metals, but the way and magnitude of the influence depended on the aqueous pH. The addition of DFOB enhanced the sorption of these heavy metals at pH below 6.5, while the opposite trend was observed at pH above 6.5 owing to the formation of complexes between DFOB and heavy metals. These results indicated that DFOB negatively influences the immobilization performance of heavy metals by MgO because the addition of MgO increases the soil pH to around 10. In fact, the results of leaching tests performed with leaching solutions of pH5.8-6.3 at a solid-liquid ratio of 1:10 (w/v) revealed that DFOB increased the leaching levels of both lead and cadmium.
