Construction of magnetically separatable Mg/Fe bimetallic oxide-loaded biochar/sodium alginate aerogel beads for enhanced uranium(VI) capture

Due to the radioactivity and chemical toxicity of uranium(VI), the treatment of uranium-containing wastewater from the uranium leaching process is a problem that has to be faced. Many of the adsorbents currently developed for use in recovering uranium from solution face problems of being difficult to recover and prone to secondary contamination. In order to achieve efficient uranium capture and easy recovery of the adsorbent, a modified biochar aerogel bead (SA@MFBC) was synthesized using Mg/Fe bimetallic oxide-modified biochar (MFBC) and sodium alginate (SA). Notably, the developed SA@MFBC-1:2 aerogel beads had a high surface area and good thermal stability. Excellent mechanical and magnetic properties predict the ability of aerogel beads to be recovered by magnetic fields. The abundant porous structures and functional groups endowed the SA@MFBC-1:2 with a high adsorption capacity of 545.35 mg.g(-1) in the adsorption process. Even after five cycles, 80 % of the adsorption capacity was maintained. Dynamic adsorption results also showed the value of aerogel beads for practical applications. Although batch experiments demonstrated that increasing the content of modified biochar in the aerogel beads helped to increase the adsorption capacity, leaching experiments of Mg and Fe at different pH also seemed to indicate that blindly increasing the biochar in the aerogel beads could also lead to secondary contamination of the solution.