Efficient removal of iodide anion from aqueous solution with recyclable core-shell magnetic Fe3O4@Mg/Al layered double hydroxide (LDH)

• Published in: The Science of the total environment Vol. 705; p. 135814
• Main Authors: Jung, Il-Kwon, Jo, Yongheum, Han, Sol-Chan, Yun, Jong-Il
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.02.2020
• Subjects: Adsorption; Iodide removal; Magnetic layered double hydroxide (LDH); Magnetite composite; Mg/Al ratio; Recyclable adsorbent; Recyclable adsorbent; Mg/Al ratio; Iodide removal; Magnetic layered double hydroxide (LDH); Adsorption; Magnetite composite
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.135814

Magnetic Mg/Al layered double hydroxides (LDH) with three cationic ratios (Mg/Al = 2:1, 3:1, and 4:1) were successfully synthesized and utilized for the first time in an iodide adsorption study. The effects of the Mg/Al ratio of LDH on iodide adsorption were investigated, and physicochemical properties of synthetic LDHs depending on Mg/Al ratio were confirmed by XRD, TEM, ICP-OES, VSM, Zeta-potential, and BET analyses. The ferrimagnetic property was well preserved even after a coating of LDH on magnetite irrespective of the Mg/Al ratio. Among the three Mg/Al ratios, the calcined Fe3O4@4:1 Mg/Al LDH exhibited excellent performance for iodide removal with 105.04 mg/g of the maximum iodide adsorption capacity due to its wide interlayer spacing and largest BET surface area. In the presence of competing carbonate anions, the Fe3O4@4:1 LDH showed removal rate of >80% at a dosage of over 3 g/L solid to liquid ratio. The recyclability test of Fe3O4@4:1 LDH showed that the removal performance for iodide is maintained at >80% even during the first to the fourth cycles. These results demonstrated that the magnetic Mg/Al LDH adsorbent can be effectively utilized for remediation of radioactive iodide anions with high efficiency and economics. [Display omitted] •Magnetic Fe3O4@Mg/Al LDHs were successfully synthesized via co-precipitation.•Their physical properties were evaluated depending on the Mg/Al ratios.•The 4:1 Fe3O4@Mg/Al LDH was determined to be optimal for iodide adsorption.•The magnetic LDH is effective for iodide removal under various aquatic conditions.