Rapid Sequestration of Mercuric Ion as HgSe by a Selenocysteine-Inspired System

The sequestration of mercuric ion as insoluble mercury selenide (HgSe) is considered the best way to close the mercury cycle. Inspired by nature, this study presents the rational design and synthesis of a novel system incorporating -SeCH₂CH₂NH₂ units on a 1,3,5-triazine ring. It showed mercuric ion sequestration within 10 min as HgSe under ambient conditions, while HgS formation from the sulfur analogue was not observed. The work was duly supported by various control experiments along with ICP-MS and DFT calculations. These results provide valuable insights into hitherto unknown mechanistic aspects of mercury detoxification by selenoproteins and offer a new design strategy for next-generation systems to carry out permanent mercury sequestration in aqueous environments.