A novel (N,Fe)-dual-functional biosorbent (N/Fe-DB) capable of efficient synergistic removal of Ni(II) and H2PO4- from aqueous solution was synthesized. The adsorption capacities of Ni(II) and H2PO4- were both remarkably enhanced over 3 times compared with those in single systems. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed that complexation of amino groups and ligand exchange of hydrous ferric oxide in N/Fe-DB played dominant roles. The electric double layer compressing and chelating ligand of deprotonated H2PO4- accounted for the enhanced removal of Ni(II) in binary system, while cation bridge interaction promoted uptake of H2PO4-. Furthermore, the coadsorbates were sequentially recovered, with the ratios of more than 99.0%. Besides, the recovered N/Fe-DB remained stable and applicable to the treatment of real electroplating wastewater even after six adsorption-regeneration cycles. Since the electroplating industry is springing up, effective control of heavy metals and phosphate has attracted global concerns. Based on the enhanced coremoval properties and superb regenerability, N/Fe-DB is potentially applicable to practical production.
Keywords: (N,Fe)-dual-functional bio-sorbent; Interaction mechanisms; Nickel; Phosphate; Synergistic removal.
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