Biogenic plant mediated synthesis of monometallic zinc and bimetallic Copper/Zinc nanoparticles and their dye adsorption and antioxidant studies

Abstract

• The eco-friendly Zn NPs and Cu/Zn NPs were synthesized by using an aqueous extract of Mirabilis Jalapa. • Synthesized Zn NPs and Cu/Zn NPs were assessed for their antioxidant potential. • The Cu/Zn NPs possessed greater antioxidant and dye removal efficacy as compared to their monometallic counterpart. • Antioxidant potential of nanoparticles, determined by DPPH radical scavenging method 72% and 89.5%. In the present research zinc (monometallic) and copper/zinc (bimetallic) nanoparticles were synthesized using the green approach. Aqueous extract of Mirabilis Jalapa was used for the reduction of zinc and copper salts to generate zinc (monometallic) and copper/zinc nanoparticles (bimetallic). The morphology, crystal structure and elemental composition of the constructed nanoparticles were evaluated by SEM, Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD) and energy dispersive X-ray (EDX) studies. The constructed nanoparticles were evaluated for their antioxidant ability. Antioxidant potential of nanoparticles, as determined by DPPH radical scavenging method was found to be 72% for Zn monometallic NPs while 89.5% scavenging potential was recorded for copper/zinc bimetallic nanoparticles at the concentration of 1500 μg/ml. Percentage scavenging potential was found to be increased with an increase in concentration. Zinc nanoparticles had total antioxidant activity and total phenolic content of 1.263 and 296 (mg/g GAE), whereas copper/zinc had 2.06 and 287 (mg/g GAE). The percentage removal of Congo red and methylene blue dyes was chosen by varying different parameters such as time, temperature, pH, adsorbent dose, and concentration of adsorbate. Results showed better removal efficacy of dyes with Cu/Zn nanoparticles as compared to the Zn nanoparticles.