Voltametric detection of methylene blue dye in water at green and chemically synthesized Ag/MWCNT modified electrode

Abstract A well-known textile dye, methylene blue (MB) was electrochemically detected by using glassy carbon electrode (GCE), modified with green and chemically synthesized silver nanoparticles (AgNPs) decorating the surface of functionalized multiwalled carbon nanotubes ( f MWCNT). The green and chemical methods were used to synthesize AgNPs, which decorated MWCNT forming MWCNT/Ag chm and MWCNT/Ag grn nanocomposite. Comprehensive characterization of the nanomaterials was carried out using energy-dispersive x-ray spectroscopy (EDX) detector-equipped scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV), and x-ray diffraction (XRD). Using XRD, particle sizes were found to be 26.81, 10.05, 5.36, 19.26, and 17.48 nm for Ag chm , Ag grn , MWCNT, Ag chm /MWCNT, and Ag grn /MWCNT, respectively. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave voltammetry (SWV) were employed for the investigation of the electrochemical properties and behaviour of MWCNT, Ag chm , Ag grn , Ag chm /MWCNT, and Ag grn /MWCNT electrodes, and higher electron transport capabilities and improved electrochemical activity towards MB on Ag chm /MWCNT electrode were demonstrated by the results. Electroanalysis of methylene blue at the modified electrodes with square wave technique SWV was successful. At Ag chm /MWCNT modified electrode, a low limit of detection (LOD) of 4.684 and limit of quantification (LOQ) of 14.194 pM, for MB, while at Ag grn /MWCNT modified electrode , an LOD and LOQ of 2.935 and 8.895 pM, were recorded respectively. In real sample analysis, the recovery percentage for Ag chm /MWCNT ranged from 90 to 98% (n =3), and Ag grn /MWCNT showed a recovery percentage ranging from 97 to 103% (n = 3). Both electrodes’ remarkable recovery rate attest to their dependability and sensitivity in MB detection.