Tannin cross-linked polyethyleneimine for highly ef fi cient removal of hexavalent chromium

A new catecholamine polymer, tannin-polyethyleneimine (TA-PEI) was fabricated via mussel-inspired polymerization for highly efficient hexavalent chromium (Cr(VI)) adsorption. The TA-PEI adsorbent was prepared with a mass ratio of TA to PEI of 3:1. This adsorbent had an ultra-high Cr(VI) removal capacity because of its amines and phenolic hydroxyl groups, with values reaching 707.96 mg/g under 308 K, which is higher than that of most PEI-based and TA-bearing adsorbents. The developed adsorbent also achieved rapid Cr(VI) adsorption, with adsorption capacity values reaching 554.94 mg/g in 15 min. Further, it displayed excellent chemical reduction ability when converting Cr(VI) to low toxicity Cr(III), as well as its good adsorption selectivity of Cr(VI) in a solution bearing coexisting ions. In a continuous adsorption experiment, the adsorbent exhibited a Cr(VI) solution treatment capacity of up to 30 L/g with a Cr(VI) concentration of 10 ppm. With its high adsorption capacity and rapid adsorption rate, this low cost and easily prepared adsorbent may have widespread potential for Cr(VI) removal and enrichment. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The novel tannin-polyethyleneimine (TA-PEI) adsorbent fabricated via mussel-inspired polymerization exhibits highly efficient hexavalent chromium (Cr(VI)) adsorption capacity, with ultra-high Cr(VI) removal capacity and rapid adsorption rate. The adsorbent also shows excellent chemical reduction ability when treating Cr(VI) solutions.