Synthesis and Characterization of Copper (Cu) Nanoparticles from Copper Tailing and Reagent Copper Salt Using Sodium Borohydride as a Reductant

Mine tailing is the waste materials left after the excavation of valuable mineral resources. It is an environmental pollutant which are often rich in metal ions, can be harnessed and used as a reagent salt substitute to synthesize nanoparticles. The copper tailings can be managed by converting it to copper nanoparticles for various purposes. This research is focused on conversion of waste (excavated copper waste) to wealth (copper nanoparticles). The synthesis of copper nanoparticles from tailings is a novel approach of recovering copper from copper tailings. The aim of this research is to synthesize and characterize copper (Cu) nanoparticles from copper tailings and reagent copper salt using sodium borohydride as a reductant. Chemical reduction method was used in the synthesis of copper nanoparticles from copper tailings and reagent copper salt Experimental approach: Pulverized copper tailing (PCT) particles was digested and the filtrate was analyzed to identify and quantify the cations and anions using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Ion Chromatography (IC) respectively. The digested filtrate was used to synthesize copper nanoparticles by chemical reduction method. Characterization of the synthesized copper nanoparticles was conducted using techniques such as X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), ThermoGravimetric Analysis (TGA), Fourier Transform Infrared (FTIR), Bruner Emmett Teller (BET), Scanning Electron Microscopy (SEM) and the Transmission Electron Microscopy (TEM). Results: The ICP-OES identified Cu from PCT to be the predominant cation (1355.25 mg/L), and IC identified sulphate (838.50 mg/L) to be the predominant anion. The XRD of the particles are crystalline. TGA results revealed the stability of PCT, Synthesized tailing Cu NPs and reagent Cu NPs at 282.31°C, 297.70°C, and 311.37°C while BET shows the surface area at (157.52 m<sup>2</sup>/g), (178.54 m<sup>2</sup>/g), and (189.93 m<sup>2</sup>/g) respectively. The SEM and TEM revealed spherical particle shape for all the samples. In conclusion: the quality of the synthesized tailing Cu NPs and reagent Cu NPs are almost similar. Also, the PCT can be used as a substitute to reagent copper salt to synthesize Cu NPs. The novelty of this research is comparing Cu NPs synthesized from tailing and reagent salt.