Spongy Crosslinked Branched Polyethylenimine-Grafted Dithiocarbamate: Highly Efficient Heavy Metal Ion–Adsorbing Material

Abstract

To remove heavy metals from polluted water efficiently and cost-effectively is a big challenge. This paper reports on a spongy crosslinked branched polyethylenimine-grafted dithiocarbamate (CBP-G-D) adsorbing material, which was prepared by crosslinking branched polyethyleneimine (PEI) with glutaraldehyde to form a crosslinked polymer, and then reducing the resulting C = N double bonds with sodium borohydride to give a crosslinked polyamine polymer and finally grafting on it with carbon disulfide. Scanning electron microscopy (SEM) verified that it was a spongelike three-dimensional network material. At room temperature, the material can efficiently uptake heavy-metal ions such as cadmium (II), copper (II), and lead (II) from wastewater based on complexation and van der Waals force. Its adsorption capability for cadmium (II), copper (II), and lead (II) reached 1.83, 3.23, and 2.18 mmol/g within 40 min, respectively; the removal percentages reached 99.85%, 99.38%, and 99.82%, respectively. Another advantage of this material is its recyclability.