Efficient removal and rapid detection of Hg2+ in environment by multifunctional binding strategy on polystyrene microspheres

Abstract

Nowadays, developing a multifunctional platform with the ability to detect and remove heavy metal ions remains a huge challenge in the field of environmental pollution control. Herein, L-cysteine functionalized novel polystyrene microspheres with special fluorescent scattering effect are constructed by simple one-step reaction. This multifunctional platform is very attractive in terms of mercury ion removal and detection. To achieve the purpose of removal, polystyrene-L-cysteine (PS-LCYS) have a lot of active sites (-SH/-NH2/-OH), which can coordinate with Hg2+ to form new complexes (PS-LCYS-Hg2+). Interestingly, fluorescent scattering was enhanced with the addition of Hg2+, indicating PS-LCYS can be used to detect Hg2+. As expected, this strategy achieved a low detection limit of 85 nM in a wide range of 50–1700 μM. At the same time, target-induced aggregation rendered the effective embedding and encapsulation of Hg2+ by PS-LCYS, showing good absorption of 92.69–94.32% within 10 min. And the maximum Hg2+ absorption capacity of PS-LCYS was estimated to be 1314 mg/g. What’s more, this platform can be regenerated and reused with the treatment of EDTA, achieving 88.54% removal rate after 7 circulations. This multifunctional platform not only realized high sensitivity detection, but also can absorb a large number of mercury ions in the water environment in a short time. After repeated use, PS-LCYS still maintained good detection and adsorption performance. Therefore, the platform had the potential to solve the problem of heavy metal ion pollution.