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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.;

Aqueous extracts of the leaf, stem and root of Echinochloa pyramidalis have been used as a reducing agent to synthesize silver nanoparticles. The synthesized nanoparticles were characterized by UV, FTIR, SEM, TEM and XRD. The nanoparticles showed absorption spectra in the visible region and crystallite sizes of 14, 2.70 and 4.9 nm for the leaf, stem and root-based nanoparticles while the respective particle sizes were 15.3, 12.6 and 10.3 nm respectively. The FTIR spectra of the nanoparticles indicated evidence of changes in the functional groups that indicated an interaction between the nanoparticles and the phytochemicals in the respective plant parts. Micrographs obtained from scanning electron microscope (SEM) reveal some protruding internal structures. The synthesized nanoparticles were also used as precursors to synthesize nanocomposites by combining them with the leaf, stem and root of the Echinochloa pyramidalis of the plant. The nanoparticles and the corresponding nanocomposites showed pore sizes that define mesoporous dimension, functional groups that were comparable to those in the parent nanoparticles, and modified surface morphology. However, BET surface area to volume ratios were relatively higher for the composites than the nanoparticles while the reverse trend was observed for pore diameter and pore volume. The composites were found to be excellent adsorbents for the removal of some PAHs from bitumen seepage water and recorded an average minimum removal efficiency of 90% and a maximum of almost 100%.

This study present the solid state synthesis of Copper (II) and Nickel (II) Complexes of Rhodanine with molecular formula [Cu(HRD)2(CH3COO)2] represented as 1a and [Ni(HRD)2(NO3)2] (HRD = C3H3NOS2) represented as 2a. It was synthesized by mechanochemical grinding of stoichiometric amount of Rhodanine with inorganic salts (Cu(CH3COO)2·H2O) and Ni(NO3)2·6H2O in ratio 1:1 via an analytical mortar and pestle without solvent. However, the solvent based approach for the synthesis of Copper (II) and Nickel (II) Complexes of Rhodanine involve the use methanol at room temperature. The complexes were characterized via elemental analysis, TLC, FT-IR, UV–visible, AAS, spectroscopies, conductivity measurement and PXRD patterns. The spectroscopic and analytical data obtained from the two methods are almost identical. The PXRD patterns of the product obtained from the solid state approach showed a close match with that of the solvent-based product. The complexes showed new peaks which established the occurrence of a new phase. The antibacterial activities of the complexes were higher than the parent ligands. This suggested that the antimicrobial efficacy of these drugs could be improved by chelation. The solid based synthesis of these complexes was faster, required less energy and produce better yield when compared with the solvent based method.