A reusable reduced graphene oxide-cobalt oxide nanocomposite with excellent yield as adsorbent for determination trace-level of brilliant green in environmental water samples

Abstract

In view of large-scale production, usage and toxic nature, the synthetic dyes are a very significant category of pollutants. This work reports the preparation and application of reduced graphene oxide/cobalt oxide (rGO/Co₃O₄) nanocomposite as selective and regenerable magnetite nanosorbent for the preconcentration and determination of brilliant green (BG) as a synthetic dye by UV–Vis spectrophotometry. The properties of the rGO/Co₃O₄ nanocomposite were characterized by UV–Vis spectrophotometry, Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, vibrating sample magnetometer and inductively coupled plasma optical emission spectrometry. Magnetic dispersive microsolid phase extraction (MD-μSPE) as a green, simple and sensitive method has been proposed for the separation and determination of trace quantities of BG. The experimental parameters affecting the MD-μSPE efficiency for the target analytes such as sample pH, brilliant green concentration, adsorbent dose and sonication time were investigated and optimized by central composite design coupled with desirability function approach. Under the optimized conditions, the detection limit, relative standard deviation and enrichment factor were 2.6 ng mL⁻¹, 3.34% (n = 5) and 24.5, respectively. Finally, the applicability of the proposed method was successfully evaluated by the determination of trace amounts of BG in fish breeding pool and tap water samples.