Hyaluronic acid-based hydrogel for cadmium removal and enhanced sorghum growth under cadmium stress

Cadmium (Cd) is a highly toxic heavy metal that poses a threat to environmental and human health. The hydrophilic and modifiable properties of hyaluronic acid (HA) render it well-suited for advanced environmental absorbent technologies. However, the potential of HA-based hydrogels in environmental applications remains largely unexplored. In this study, HA modified with dopamine (DA) and tannic acid (TA) was first synthesized. Then a novel renewable multi-network hydrogel (HDT) was developed through a simple one-step free radical polymerization. Herein, DA enhances stability by improving coupling through self-polymerization and TA's phenolic groups enable superior metal ion chelation. The HDT hydrogel demonstrated stability, sustainable absorption, and desorption, regeneration capabilities, antibacterial properties, and a notable Cd absorption capacity of 161 mg/g. As the hydrogel absorbed Cd initially, thereby minimizing its biological accessibility and plant root absorption, sorghum seedlings treated with the HDT hydrogel exhibited healthier growth patterns and lower internal Cd concentrations compared to untreated controls in Cd-contaminated environments, ultimately contributing to an approximate 53.2 % total Cd removal. Therefore, our project introduces a promising approach to deliver dual benefits in alleviating the environmental effects of Cd contamination while simultaneously promoting sustainable agricultural practices.