Sargassum@magnetite Composite EDTA-Functionalized for the Potential Removal of Mercury

Sargassum spp. affects the Caribbean shores; thus, its remotion or valorization is a priority. This work aimed to synthesize a low-cost magnetically retrievable Hg⁺² adsorbent functionalized with ethylenediaminetetraacetic acid (EDTA) based on Sargassum. The Sargassum was solubilized to synthesize by co-precipitation a magnetic composite. A central composite design was assessed to maximize the adsorption of Hg⁺². The solids yield magnetically attracted mass, and the saturation magnetizations of the functionalized composite were 60.1 ± 17.2%, 75.9 ± 6.6%, and 1.4 emu g^-1. The functionalized magnetic composite yielded 29.8 ± 0.75 mg Hg⁺² g^-1 of chemisorption after 12 h, pH 5, and 25 °C achieving 75% Hg⁺² adsorption after four reuse cycles. Crosslinking and functionalization with Fe₃O₄ and EDTA created differences in surface roughness as well as the thermal events of the composites. The Fe₃O₄@Sargassum@EDTA composite was a magnetically recovered biosorbent of Hg²⁺.