Water-insoluble polyethyleneimine adsorbents for the high-efficiency removal of Hg(ii) from aqueous solution

Abstract

Polyethyleneimine (PEI), with an abundance of amino groups, demonstrates a strong affinity for heavy metal ions, thus emerging as a promising candidate for applications in wastewater treatment. However, the inherent water solubility of PEI limits its direct use for the remediation of heavy metals. Contrary to the previous synthetic approaches that employed PEI solely as a surface modifier, the present work utilizes the PEI polymer as the fundamental matrix for the development of water-insoluble polyethyleneimine derivative adsorbents (PAPEI). This innovative method eliminates the need for additional solid substances, enabling the effective elimination of Hg(II) from aqueous solutions. PAPEI adsorbents achieved a high adsorption capacity of 1832 mg g⁻¹ for Hg(II) with a good selectivity (distribution coefficient K_d = 3.2 × 10⁴ mL g⁻¹). The adsorption process between the PAPEI adsorbents and Hg(II) was primarily attributed to chelation affinity. This work proposed a straightforward approach for designing PAPEI adsorbents that can efficiently remove Hg(II) from aqueous environments.