A versatile β-cyclodextrin functionalized silver nanoparticle monolayer for capture of methyl orange from complex wastewater

Abstract The toxic organic dye contaminants in wastewater are extremely harmful to the ecosystem. Surface enhanced Raman scattering (SERS) is a technique with high sensitivity and chemical specificity which fulfills the requirements for monitoring dye contaminants in wastewater. However, as one of the common dye contaminants, methyl orange (MO) has very weak affinity to metallic surfaces and is difficult to be detected by SERS at low concentrations. Therefore, a new type of SERS substrate with Ag nanoparticle monolayer functionalized by mono-6-deoxy-6-thio-β-cyclodextrin (β-CD-SH) was prepared to efficiently capture and detect MO in wastewater with a limit of detection of 5 × 10−7 mol/L. The hydrophobic cavity of β-CD is responsible for the efficient trap and enrichment of MO on the Ag NPs surface, achieving a strong SERS signal of MO at low concentrations and at different pH values. This study provides new insight into designing a well-performed adsorbent for the capture and detection of organic contaminants.