Remediation of Nano-/Microplastics from Water via Superparamagnetic Core- Shell Nanoparticles - RePLAST

• Applicant: Professor Dr. Marcus Halik
• Subject Area: Solid State and Surface Chemistry, Material Synthesis ; Synthesis and Properties of Functional Materials
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 542274919

With RePLAST we will elaborate non-covalent interaction of different nano- and microplastics (MNPs) with particularly functionalized superparamagnetic iron oxide nanoparticles (SPIONs) in order to improve their efficient agglomeration (Plastics/SPIONs) and by this to boost the performance in remediation of the plastic debris from water via external magnetic field. Based on the aproffed remediation concept, we will explore the impact of increasing surface charge of the SPIONs as major driving force for the interaction to oppositely surface-charged plastic debris. Additionally, we will investigate the impact of hydrogen bonding in particular on weathered MNPs. We will tune the SPION surface by introducing different phosphonic acid based shell molecules (dipolar, charged, multiple charged and OH-terminated) with special emphasis to generate positive surface charges and H-bonding motifs. Conceptually we will self-assemble charged molecules (top down) or post quaternization of neutral amines (bottom up). In order to understand and to improve the already observed selectivity of SPIONs to MNPs in competition to inorganic nanoparticles/sediments of similar surface charge, we will systematically investigate and compare monolayer shells with charged head groups to monolayers where the charges are embedded in a hydrophobic backbone. The MNP-remediation performance of the new SPION systems will be quantified towards their maximum nanoplastics collection capability (NCC). With the threshold NCC we will benchmark our analytical method towards low concentrations of MNPs. The selection of the MNP represent common and commodity polymers of different chemical composition (PE, PS, PMMA and one melamine resin- MR) of two sizes ranges (50 – 100 nm and 1 – 10 micron). SPION-MNP interaction will be investigated for pristine and weathered MNP samples. Additionally, we will investigate the potential of the novel SPION systems in real water samples from sewage plant wastewater to mudflat. Finally, we will monitor the toxicity of the best performing novel SPIONs. With RePLAST we believe to deliver a fundamental understanding of surface interaction of nano- and microplastics with functional SPION surfaces and to identify molecular motifs for highly efficient remediation of small plastic debris.

• DFG Programme: Research Grants