Mercury Uptake by Modified Mackinawite

This study investigated the mercury uptake capacity of synthetic mackinawite regarding its surface modification with L-cysteine. Mackinawite (FeS) is an excellent material for mercury uptake from anoxic-contaminated sediments. However, one limitation to its use is the low oxidation stability; it is easily transformed when applied to natural sediments. The modification of mackinawite with L-cysteine improves its oxidation stability, making it a promising material to be used in sediment remediation by in-situ capping. The results showed that L-cysteine does not affect the mercury-uptake capacity of mackinawite (around 490 mg/g for modified and unmodified mackinawite). The Hg (II) uptake decreased as the solution pH changed from acid to alkaline range, especially in solutions with low Hg (II) concentrations. Sorption curves for Hg (II) on modified mackinawite, as a function of initial concentration of Hg (II) and mackinawite, showed the same pattern as that on unmodified mackinawite, indicating no significan...