Design of GO–Ag-functionalized Fe3O4@CS composite for magnetic adsorption of rhodamine B

Abstract

In this study, a novel magnetic composite (Fe₃O₄@CS/GO/Ag) modified with chitosan (CS), graphene oxide (GO) and Ag nanoparticles (Ag NPs) was successfully prepared as an efficient adsorbent for detection of rhodamine B (RB) combined with a fluorescence technique. The properties of the magnetic composite were confirmed by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and vibrating sample magnetometry. The components of Fe₃O₄@CS/GO/Ag endowed it with excellent extraction performance and convenient operation. The main parameters affecting extraction and desorption efficiency were all investigated systematically. Under the optimized experimental conditions, the proposed method showed linear ranges (0.2–6.0 μg L⁻¹) with R² = 0.9992. The limits of detection (LODs) and quantification (LOQs) were 0.05 and 0.2 μg L⁻¹ (n = 3), respectively. Fe₃O₄@CS/GO/Ag exhibited outstanding extraction efficiency for RB, compared with CS-coated Fe₃O₄ nanoparticles (Fe₃O₄@CS) and GO-modified Fe₃O₄@CS (Fe₃O₄@CS/GO). The applicability of the proposed method was investigated by analyzing four real samples (waste water, soft drink, shampoo, and red pencil) and the spiked recoveries ranged between 94% and 97% with RSD ranging from 3% to 6%, which showed that the proposed method had satisfactory practicability and operability.