Thiol modified Fe3O4@SiO2 as a robust, high effective, and recycling magnetic sorbent for mercury removal

By Shengxiao Zhang, Yuanyuan Zhang, Junshen Liu, Qiang Xu, Huaqing Xiao, Xinyu Wang, Hui Xu, Jing Zhou. 2013

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abstract The SiO 2 shell was coated on Fe 3 O 4 nanoparticle by hydrolyzation of Na 2 SiO 3 , and then thiol groups weremodified on the Fe 3 O 4 @SiO 2 through silanization reaction to form Fe 3 O 4 @SiO 2 –SH sorbents. Characteriza-tion with transmission electron microscope (TEM), Energy-dispersive spectroscope (EDS), and X-ray pho-toelectron spectroscopy (XPS) proved that SiO 2 and thiol groups were successfully covered on the surfaceof Fe 3 O 4 nanoparticle. The Fe 3 O 4 core possessed superparamagnetism for magnetic separation, and theSiO 2 shell could protect the Fe 3 O 4 core from being oxidized or dissolved under acid solution and providegood modificability. Due to the strong interaction between mercury and thiol groups, the synthesizedsorbents exhibited high adsorption capacity and good anti-interference ability during mercury adsorp-tion. The maximum adsorption capacity calculated from Langmuir fitting was 148.8 mg/g at pH 6.5,and the sorbents still maintained good adsorption ability at low solution pH and high concentration ofcoexisting cations. Mercury loaded on the sorbents could be easily desorbed with 1 mol/L HCl containing3 wt.% of thiourea, and the sorbents showed good reusability. The adsorption capacities were still keptover 110 mg/g in tested natural water samples, showing practical significance in remediation of mercurycontaminated actual water. 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Subfields: Analytical Chemistry, Health, Toxicology and Mutagenesis, Water Science and Technology

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