Multifunctional 3D magnetic carbon aerogel for adsorption separation and highly sensitive SERS detection of malachite green

This work presents a novel strategy for the synthesis of a recyclable aerogel and its multifunctional application as effective adsorption material for organic pollutants and as a high-quality SERS substrate for on-site detection measurement. Silver nanoparticles (Ag NPs) were uniformly dispersed and adsorbed on the surface of an Fe3C-loaded carbon aerogel, resulting in the formation of a three-dimensional Ag–Fe3C–MCA (magnetic carbon aerogel) composite. The substrate preparation led to Ag–Fe3C–MCA with a mesoporous structure for high adsorption capacity, together with magnetic properties for easy separation capability. The Ag–Fe3C–MCA composite demonstrated an efficient removal ability for malachite green (MG), with an adsorption capacity of 296.7 mg g−1. Moreover, Ag–Fe3C–MCA composite provided ultrasensitive surface-enhanced Raman scattering detection for MG molecules, obtaining a limit of detection (LOD) of 3 × 10−10 M. Aquaculture water samples with spiked MG concentrations were used to simulate practical scenarios. The Ag–Fe3C–MCA presented has a significant potential for the removal of hazardous residues in wastewater, together with an efficient and sensitive method of quantification, all on the same substrate. © 2023 Elsevier Ltd