Total removal of Hg (II) from wastewater using magnetic nanoparticles coated with nanometric Ag and functionalized with sodium 2-mercaptoethane sulfonate

• Published in: Environmental chemistry letters Vol. 18; no. 3; pp. 975 - 981
• Main Authors: Vicente-Martínez, Y., Caravaca, M., Soto-Meca, A.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.05.2020; Springer Nature B.V
• Subjects: Adsorbents; Adsorption; Analytical Chemistry; Analytical methods; Aquatic environment; Aqueous solutions; Earth and Environmental Science; Ecotoxicology; Electron microscopy; Emission analysis; Environment; Environmental Chemistry; Field emission microscopy; Geochemistry; High temperature; Low concentrations; Mercury; Mercury (metal); Nanoparticles; Original Paper; Pollution; Procedures; Removal; Room temperature; Scanning electron microscopy; Silver; Sodium; Sulfonates; Wastewater; X-ray spectroscopy; Removal; Adsorption; Mercury; Kinetic studies; Magnetic nanoparticles
• ISSN: 1610-3653; 1610-3661
• DOI: 10.1007/s10311-020-00987-x

Divalent mercury (Hg (II)) is the predominant mercury species in aquatic environments. Hg (II) combines easily with human enzymes, thus causing acute diseases, even at very low concentrations. Among existing procedures to remove Hg (II) from water, adsorption is widely used, achieving high removal efficiencies. However, most actual adsorption techniques require high temperatures, long times or tedious procedures. Here we present a novel, simple and fast method to remove Hg (II) from wastewater by using magnetic-core nanoparticles coated with metallic silver and functionalized with sodium 2-mercaptoethane sulfonate. This adsorbent was characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Brunauer–Emmett–Teller analysis, which showed a contact surface area of the adsorbent equal to 116.476 m 2 /g. The equilibrium isotherm is characterized by the Langmuir model. Results show that 100% adsorption efficiency is achieved in 30 seconds of contact time, at pH 6.2 and room temperature, employing a low dose of adsorbent. The adsorbent can be recovered and recycled, keeping 100% adsorption efficiency for two additional cycles. The presence of other ions commonly found in aqueous media does not interfere with Hg (II) adsorption.