EDTA-based adsorbents for the removal of metal ions in wastewater

Ethylene diamine tetraacetic acid (EDTA) is an excellent chelating agent. Its two amino groups and four carboxyl groups can be used as the binding sites of metal ions. EDTA can form stable water-soluble chelates with almost all transition metal ions. Meanwhile, EDTA is grafted onto the adsorbents through physical or chemical modification to improve the performance of the adsorbents. Therefore, EDTA-based adsorbents for the removal of metal ions in wastewater have attracted extensive attention in recent years. This article reviews the advantages and disadvantages of different types of EDTA-based adsorbents from the aspects of preparation, adsorption capacity, adsorption rate, adsorption mechanism, and regeneration. In addition, the potential applications and limitations of EDTA-based adsorbents are summarized. Finally, the challenges and future development directions of EDTA-based adsorbents are prospected.