Magnetic Nanocomposites for the Remote Activation of Sulfate Radicals for the Removal of Rhodamine B

The widespread presence of numerous organic contaminants in water poses a threat to the ecological environment and human health. Magnetic nanocomposites exposed to an alternating magnetic field (AMF) have a unique ability for magnetically mediated energy delivery (MagMED) resulting from the embedded magnetic nanoparticles; this localized energy delivery and associated chemical and thermal effects are a potential method for removing contaminants from water. This work developed a novel magnetic nanocomposite—a polyacrylamide-based hydrogel loaded with iron oxide nanoparticles. For this magnetic nanocomposite, persulfate activation and the contamination removal in water were investigated. Magnetic nanocomposites were exposed to AMF with a model organic contaminant, rhodamine B (RhB) dye, with or without sodium persulfate (SPS). The removal of RhB by the nanocomposite without SPS as a sorbent was found to be proportional to the concentration of magnetic nanoparticles (MNPs) in the nanocomposite. With the addition of SPS, approximately 100% of RhB was removed within 20 min. This removal was attributed primarily to the activation of sulfate radicals, triggered by MNPs, and the localized heating resulted from the MNPs when exposed to AMF. This suggests that this magnetic nanocomposite and an AMF could be a unique environmental remediation technique for hazardous contaminants.