Selective Removal of Highly Toxic Selenite by a Biobased Zirconium-Polyphenolic Supramolecular Gel

The green and facile biobased functional materials have attracted great attention due to the promising potential to deal with the water pollution of toxic selenium ions that act as a serious threat to human health and the ecological environment. The development of cheap and eco-friendly approaches to remove SeO₃^2– is of great significance for the safety of drinking water. However, there are some disadvantages in most of the employed methods, such as poor removal capability, high cost, and unsustainability. In this paper, a novel zirconium-based metal polyphenol gel (MOGs, Zr-GA) was synthesized by using tea polyphenol-derived gallic acid (GA) as ligands to selectively capture SeO₃^2– anions from aqueous solutions with ultrahigh adsorption capacity (119.5 mg g^–1). As a natural product, the adoption of GA aligns well with the sustainable demand, making it suitable for a wide range of application fields. In addition, the adsorbent can work stably in a wide pH range (2–11) and exhibits excellent selectivity for SeO₃^2– removal. This work develops an efficient adsorption material by a simple synthesis method based on a natural product.