Removal performance and mechanism of Fe3O4/graphene oxide as an efficient and recyclable adsorbent toward aqueous Hg(II)

Decontamination of aqueous heavy metal is a challenging task of environmental remediation. Herein, we demonstrated an adsorptive method for efficient removal of aqueous Hg(II) using a magnetic nanocomposite Fe 3 O 4 /graphene oxide (Fe 3 O 4 /GO). Adsorption of Hg(II) onto Fe 3 O 4 /GO equilibrated in 4 min, with the adsorption percent and quantity of 91.17% and 547.01 mg g −1 , respectively. Fe 3 O 4 /GO can be easily recovered from solution via magnetic separation for reuse, and retaining 73.5% of its original capacity after five consecutive cycles. The Temkin model and PSO model were most suitable for describing adsorption in equilibrium and non-equilibrium state, respectively. Both GO and Fe 3 O 4 adsorbed Hg(II) via donating electrons in oxygen atoms toward Hg(II). Moreover, GO made a major contribution, while Fe 3 O 4 made a minor one to adsorption. The facile preparation, high adsorption efficiency, easy recovery, and reusability may enable Fe 3 O 4 /GO to be a promising adsorbent for aqueous Hg(II).