Magnetic Hydrogel Microbots for Efficient Pollutant Decontamination and Self-Catalyzed Regeneration in Continuous Flow Systems

The efficient removal of organic pollutants from water is crucial for protecting human health and the ecosystem. While adsorbent-based approaches offer advantages over traditional chemical and thermal methods, they still suffer from slow adsorption kinetics, high energy demand, and limited material lifespan. Herein, an efficient decontamination platform is introduced, using magnetic hydrogel microbots (MHMs) made from picolitre-sized hydrogel droplets coated with multifunctional magnetic nanoparticles. This approach includes 1) dividing a droplet into smaller microbots to enhance their interaction with sample solution and 2) dynamically spinning these MHMs to generate hydrodynamic flows that actively draw pollutants toward the embedded hydrogel for capture. The MHMs show high decontamination effectiveness in both bulk and continuous flow setups, achieving ≈95% removal efficiency within 3 min. Further integrating MHMs with a non-pressurized fluidic platform enables energy-efficient continuous flow decontamination, removing ≥95% total organic carbon from a complex pollutant mixture at a flow rate surpassing other recent designs. Additionally, the MHMs facilitate self-catalyzed regeneration using an environmentally friendly H₂O₂ precursor, allowing for long-term and repeated usage. By enabling the unique divide-and-arrest decontamination of toxic pollutants, the multifunctional design holds tremendous promise for on-site wastewater treatment to ensure safe water access for everyone, even in resource-limited environments.