Nano adsorptive extraction of diverse microplastics from the potable and seawater using organo-polyoxometalate magnetic nanotricomposites

Abstract

Due to augmented interventions of the hazardous diverse microplastics in the water resources, advanced methods of microplastics separation have been established and prospected in recent years. This work demonstrated the nano adsorptive magnetic extraction of the microplastics from the potable and seawater using magnetically retrievable organo-polyoxometalate ionic salts as nanotricomposites designated as Fe3O4-PWA/amine. Nanotricomposites were strategically synthesized in a single step via counter acidic proton exchange of POMs (Phosphotungstic acid) to the N-containing organic bases (n-Butyl, n-Hexyl, and n-Octyl amines) with simultaneous doping of Fe3O4 (II, III) nanoparticles. FE-SEM and TEM studies revealed physico-chemical magnetic adsorption of the nanotricomposites over microplastics, proving the multifunctional surface characteristics. Fe3O4-PWA/nOct nanotricomposite prepared using n-octylamine performed well with nearly complete extraction of diverse microplastics from the spiked microplastics solutions (0.01–0.0025%) in potable and seawater. Real microplastics in seawater of 24 B° also could be extracted using Fe3O4-PWA/nOct. Remarkably, the varied sizes and shapes of the microplastics did not affect the extraction process, as was confirmed by the successful implementation of the process for 1 µm polystyrene, 100–500 µm polysulphone, and irregular-sized PET particles. ICP-MS and TOC confirmed the non-leaching of the inorganic and organic components from the Fe3O4-PWA/nOct nanotricomposites after extraction, making the process environmentally benign.