Green synthesis and characterization of copper nanoparticles (CuNPs) and composites (CuC) using the Echinochloa pyramidalis extract and their application in the remediation of PAHsin water

In this study, we synthesized copper nanoparticles and nanocomposites (i.e. copper-based) using different parts of Echinochloa pyramidalis plant. The products were applied to remove seven types of PAHs identified in bitumen seepage water through adsorption. Phytochemical screening of the plant indicated phenol, tannin and saponins, which supported their ability to convert CuSO4·5H2SO4 to copper nanoparticles. Nanocomposites were also produced from the nanoparticles obtained from the respective parts of the plant. They were characterized using X-ray diffractometer (XRD), Brunauer -Emmett -Teller (BET), Fourier transformed infrared spectrophotometer (FTIR), ulraviolet visible spectrophotometer (UV), scanning electron microscope (SEM) and transmission electron microscope (TEM). We observed pore size characteristics describing microporous and mesoporous dimensions for the nanoparticles and the corresponding composites, respectively. Based on UV-visible analysis, bandgaps ranging from 3.16 to 3.40 eV were observed for the nanoparticles. The nanoparticles from the leaf, stem and root showed average crystallite sizes of 0.1623, 0.1582 and 0.2145 nm, respectively, and showed comparative d-spacing parameters. The root-, stem- and leaf-based nanoparticles exhibited adsorption removal efficiencies ranging from 74.32 to 81.70, 74.28 to 83.45 and 76.34 to 83.98%, respectively. However, the nanocomposites of the leaf, stem and root showed better efficiencies defined by the following ranges: 79.93–83.86, 79.16–83.49 and 83.23–84.01%, respectively. HIGHLIGHTS Bitumen is a potential source of future energy.; PAHs contamination of bitumen seepage water has been observed.; Nanoparticles are useful in remediating PAHs contamination from bitumen seepage water.;