3D-Printed Magnetic Polysaccharide Hydrogels as Sustainable Platforms for Pesticide Remediation

Magnetic hydrogels based on gum arabic (GA) and sodium alginate (SA) were fabricated by three-dimensional (3D) printing and functionalized with GA-stabilized magnetic iron oxides nanoparticles (GA-MNP) for the removal of the neonicotinoid pesticide imidacloprid from aqueous media. The nanoparticles (NP) preserved their crystalline magnetite structure after printing and calcium-mediated cross-linking, as confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The printed hydrogels exhibited pH-responsive swelling behavior, with maximum hydration under acidic conditions. Adsorption experiments revealed that the formulation containing the highest NP loading achieved the greatest removal efficiency, reaching an adsorption capacity of 38.46 mg·g^-1. Kinetic data were best described by the pseudo-second-order model, and equilibrium results followed the Langmuir isotherm, indicating monolayer adsorption governed by surface interactions. Overall, the combination of natural polymers, magnetic NP, and additive manufacturing provides a sustainable, efficient, and magnetically recoverable platform for the treatment of pesticide-contaminated water.