Green synthesis of zerovalent copper nanoparticles for efficient reduction of toxic azo dyes congo red and methyl orange

Abstract

In this study, plant-mediated copper nanoparticles (CuNPs) were synthesized. Due to its direct synthesis mechanism and eco-friendly nature, the current method accounts for the green chemistry approach using the fruit extract of Duranta erecta for the first time. The UV-visible spectrum of the CuNPs solution showed a distinct absorption peak at 588 nm. Fourier transform infrared spectroscopy confirmed that the fruit extract is responsible for the reduction as well as the stabilization of CuNPs. X-ray diffraction patterns conform the crystalline nature of CuNPs. Energy-dispersive X-ray spectroscopy was performed for elemental analysis whereas field emission scanning electron microscopy was carried out for surface morphology. Prepared CuNPs were used for the reduction of carcinogenic azo dyes methyl orange (MO) and congo red (CR). CuNPs exhibit outstanding catalytic reduction for MO and CR in the presence of NaBH4 as reducing agents with the pseudo-first-order rate constants of 8.6×10−3 s−1 and 5.07×10−3 s−1 for MO and CR, respectively. Thus, natural plant materials act as cheap and environmentally friendly support for the synthesis of CuNPs and could be used for the purification of water from organic dye effluents.

Biogenic copper nanoparticles and their applications: A review

“…The maximum absorption peak was 560 nm, with XRD average particle size 48 nm as reported by Nagar and Devra [115]. Ismail et al [116] recorded the characteristic absorption peak of Cu colloids at 588 nm with XRD average crystallite size 76 nm. Summary of UV-Visible data and particle size of copper nanoparticles tabulated in Table 3.…”

“…In 2019, zerovalent Cu NPs were synthesized by using Ripened Duranta erecta fruit [116] extract to reduce toxic azo dyes congo red and methyl orange from water. The flower, leaf, and stem of Gnidia glauca and Plumbago zeylanica [117] extract is used to get Cu NPs which applied as an antidiabetic agent.…”

Plant‐supported silver nanoparticles: Efficient, economically viable and easily recoverable catalyst for the reduction of organic pollutants

“…The XRD pattern of Ni/GP displayed a diffraction peak at 2 θ = 48.8° corresponding to characteristic Braggs peak of (200) . In the XRD pattern of Cu/GP, two distinct diffraction peaks for Cu were observed at 2 θ values of 43.42° and 50.62° representing Bragg reflections of [111] and [200] planes of face‐centred cubic crystal structures of Cu nanoparticles . Average crystallite size was calculated from the XRD data of the prepared nanoparticles using the Scherrer equation, where the average particle size was determined by the full width at half maximum of the intense peak at 2 θ = 28.05°.…”

“…For instance, we recently reported chitosan filter paper loaded with Cu nanoparticles, which took 13 min for the reduction of 4 ml of 0.012 mM CR . Since reduction of CR by NaBH 4 obeys pseudo‐first‐order kinetics, for the determination of the rate of CR reduction, the pseudo‐first‐order equation was used. The rate of reaction can be determined and expressed from the relative intensity of absorption peaks at time t .…”

One‐pot green synthesis of Cu/bone nanocomposite and its catalytic activity in the synthesis of 1‐substituted 1H‐1,2,3,4‐tetrazoles and reduction of hazardous pollutants

“…The biosynthesis of NPs has attracted particular attention owing to its inherent characteristics, including use of natural products, lack of toxicity, rapidness, and providing conditions to synthesize controlled and well‐defined size of NPs . These interesting features are necessary for medical applications.…”