Cyclea peltata Leaf Mediated Green Synthesized Bimetallic Nanoparticles Exhibits Methyl Green Dye Degradation Capability Asha R. Suvarna 1 & Anvitha Shetty 1 & Sneha Anchan 1 & Nasreena Kabeer 1 & Sneha Nayak 1 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Nowadays, biological materials are explored widely for green synthesis of nanoparticles because of its ease in scaling up when compared with conventional approaches. In this paper, we report the biosynthesis of bimetallic nanoparticles (FeCuNPs) from their precursors FeSO 4 and CuSO 4, using Cyclea peltata leaf extract. Biosynthesized nanoparticles were characterized by UV- visible spectroscopy, particle size analyser, FESEM, EDAX, XRD and FTIR. UV-visible spectroscopic investigation confirmed the production of bimetallic core shell nanoparticles at 250 nm, where the colour change in the solution indicated the formation of nanoparticles. The synthesized FeCuNPs were tested for their methyl green dye degradation and degradation kinetics. Results indicated that bimetallic nanoparticles could effectively degrade methyl green dye up to 82% within 105 min, which followed pseudo second order kinetics with R 2 of 0.9862. Hence time-dependent reduction in methyl green absorption maxima, obtained from UV-Spectrophotometric analysis and LCMS spectra of degraded dye, confirmed that the green synthesized bimetallic nanoparticles from the leaf extract of Cyclea peltata has the potential of dye degradation. Keywords Bimetallic nanoparticles (FeCuNPs) . Cyclea peltata . Leaf extract . Biosynthesis . Degradation 1 Introduction The recent developments in the field of nanotechnology have resulted in new methods for the synthesis of nanoparticles. Nanoparticles are readily produced using physical and chem- ical methods, but the green synthesis of nanoparticles using plants and microorganisms can also be used for the efficient and rapid synthesis of nanoparticles [1]. Properties of biolog- ically synthesized nanoparticles differ from those synthesized following physico-chemical methods. Green synthesis is a bottom-up approach, in which, instead of using a chemical reducing agent, a biological extract is used for the synthesis of metallic nanoparticles [2]. The phytochemicals, proteins and enzymes present in the extract stabilizes the nanoparticles, which makes interaction with other biomolecules possible, which increases the antimicrobial activity of the nanoparticles [3]. Algae, yeast, bacteria, plants and fungi have been used for in vivo production of nanoparticles [4]. An aqueous solution of a suitable metal precursor is mixed with a biological extract in the required ratio. Reactions can be triggered by stirring or by heating. In some cases, spontaneous reaction takes place at room temperature. This is considered a better way since it reduces environmental pollution, is inexpensive, sustainable and less time consuming. A dye is an organic compound used to impart colour to paper, leather, textiles and other materials. Approximately 60% of the total dye production is used in the textile industries for the coloration of fabrics [5]. Nearly 10–15% of the dyes enter the wastewater stream and this affects the environment [6]. When dyes are released into water bodies without proper treatment, it reduces the penetration of sunlight and decreases the concentration of dissolved oxygen in water bodies. Among the various dyes, methyl green is a cationic triphe- nylmethane dye which is widely used to stain DNA, fluores- cent labelling of embryos and dying of textiles [6, 7]. Other dyes of the triphenylmethane group are known to be potential carcinogens [8]. It is known to cause irritation to the eyes, the skin, the respiratory tract and the gastrointestinal tract [9]. Due to highly toxic nature of this dye, the presence of it in Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12668-020-00739-9) contains supplementary material, which is available to authorized users. * Sneha Nayak snehanayak@nitte.edu.in 1 Department of Biotechnology Engineering, NMAM Institute of Technology, Nitte, Udupi, Karnataka 574110, India BioNanoScience https://doi.org/10.1007/s12668-020-00739-9