Green and Simple Synthesis of a Nonflammable and Broad-Spectrum Adsorbent for Uranyl and Other Metal Ions

Adsorption is an effective technology widely used in the removal of radioactive and other heavy metal ions, the adsorbent plays critical role and development of novel adsorbents is being in urgent demand. In this work, phytic acid (PA)-modified melamine sponge (MS) adsorbent MS@PDA@PA is prepared conveniently in green solvent water. A wide spectrum of metal ions including radioactive uranyl and transition heavy metal ions can be effectively adsorbed by the MS@PDA@PA due to non-selectivity of phosphoric acid groups in PA. Different factors including pH of aqueous solution, contact time, and initial concentration of ions on the effect of adsorption of the resultant materials are investigated in detail, and the maximum adsorption capacities for U(VI), Pb(II), Cu(II), Cr(III) are 166.7, 168.5, 114.3, and 101.0 mg g-1 respectively at 298 K. It is notable that the MS@PDA@PA is nonflammable due to employment of MS as frame material, and the thermal stability is even improved after incorporation of PA, greatly reduce the risk of the adsorbent in the processes of storage and usage. The green yet simple synthesis and fire resistance of MS@PDA@PA make it a competitive material for practical treatment of wastewater consisting of toxic metal ions. Nonflammable and broad-spectrum adsorbent MS@PDA@PA with high thermal stability based on melamine sponge (MS) is prepared conveniently employing the phytic acid (PA) and polydopamine (PDA) as the modifier and linking agent respectively through a green process. Radioactive uranyl and transition heavy metal ions including Pb(II), Cu(II), Cr(III) can be effectively adsorbed by the material.image