Synergy of thermoresponsive N-isopropylacrylamide/dopamine methacrylamide copolymers with iron oxide magnetic nanoparticles for chromium (VI) water remediation

Smart materials have demonstrated significant effectiveness, selectivity, and control across various applications, including water remediation. In this work, N -Isopropylacrylamide (NIPAM) was copolymerized with a lower ratio of dopamine methacrylamide (DMA) to obtain temperature-responsive copolymers with catechol functional groups. The strong affinity of catechol groups for oxide surfaces facilitated the formation of hybrids with iron oxide magnetic nanoparticles (MNPs). The inclusion of MNPs resulted in a synergistic interaction with the polymer, enhancing the abrupt change in polymer solubility above the cloud temperature (T c ). Consequently, visible polymer-MNP aggregates formed once the temperature surpassed the critical threshold. These aggregates flocculated and were easily separated from the solution using a magnet due to the presence of MNPs. Furthermore, the catechol groups effectively adsorbed Cr(VI) from the aqueous medium while maintaining aggregate formation, enabling the hybrid with the adsorbed Cr(VI) to be efficiently magnetically separated from the solution. Thus, this demonstrates the system's potential as an effective water purification method.