Preparation of Thermally Responsive Magnetic Nanocomposites for the Removal of Environmental Pollutants

Magnetic nanocomposite based sorbents have gained great attention for environmental remediation (especially water treatment) due to their magnetic separation properties and high adsorption capacities. In addition, smart magnetic sorbents that are responsive to surrounding stimulus have also been developed through the combination of magnetic nanoparticles and thermo-responsive polymers. N-isopropylacrylamide (NIPAAm) is one of the most widely studied thermo-responsive materials, which undergoes reversible phase transition at its lower critical solution temperature (LCST) around 32°C. NIPAAm-based thermally responsive materials can be synthesized with various functionalities, which can provide specific interactions with environment pollutants (e.g., polychlorinated biphenyl, PCBs). Our group’s recent efforts have focused on applying naturally derived polyphenols, such as curcumin and quercetin, to develop materials with binding affinities to PCBs. The presence of aromatic rings in polyphenols is expected to mimic the binding domains as observed in PCB antibodies (e.g., S2B1).

The overall goal of this work was to develop thermally responsive materials for on/off PCB binding purpose, aiming at provide an easy-recovery and cost effective strategy for the removal of PCBs from the environment. Specifically, two types of thermally responsive magnetic nanocomposites were developed, including magnetic nanocomposite microparticles (MNMs) and core-shell magnetic nanoparticles (MNPs). The physicochemical properties and PCB capture/release performance of the composite particles were characterized. Their size and morphology were characterized by scanning electron microscopy (SEM), the magnetic nanoparticle loading was determined by thermogravimetric analysis (TGA), the thermo-responsive was characterized by dynamic light scattering (DLS), and the magnetic separation property was characterize by a static magnetic fields.