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 Fe 3 C-loaded carbon aerogel, resulting in the formation of a three-dimensional Ag–Fe 3 C–MCA (magnetic carbon aerogel) composite. The substrate preparation led to Ag–Fe 3 C–MCA with a mesoporous structure for high adsorption capacity, together with magnetic properties for easy separation capability. The Ag–Fe 3 C–MCA composite demonstrated an efficient removal ability for malachite green (MG), with an adsorption capacity of 296.7 mg g −1 . Moreover, Ag–Fe 3 C–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–Fe 3 C–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.