Highly Efficient Removal of Mercury Ions from Aqueous Solutions by Thiol-Functionalized Graphene Oxide

Mercury ion (Hg(II)) is one of the most prevalent and dangerous heavy metal ions in the environment, and its removal from water sources is a priority for public health and ecosystem conservation policies. Adsorption is a cost-effective and efficient method for removing heavy metal ions from aqueous solutions. In this study, the thiol-functionalized graphene oxide (GO-SH) was synthesized and used for efficient removal of Hg(II) from aqueous solutions. More than 98% of Hg(II) was efficiently removed by GO-SH within 36 h. The Hg(II) removal efficiency by GO-SH treatment was approximately double that by pure GO treatment. The adsorption behavior of Hg(II) on GO-SH was well described by the pseudo-second-order kinetic and the Freundlich isotherm models. Moreover, GO-SH exhibited good stability and reusability in the cycle experiments. Analysis of the adsorption mechanism showed that Hg(II) could be loaded onto the GO-SH surface by reacting with the sulfhydryl groups. This study demonstrates that GO-SH is a promising water purification material with a high efficiency for Hg(II) removal.