Abstract
Green synthesis is a clean and eco-friendly process in which metal nanoparticles can be produced via reaction between a metal salt solution and plant organ extract. In present study, three copper oxide nanoparticles were synthesized using green synthesis processes from the leaf extracts of selected plants as abundant plant cover in the study area including astragalus (Astragalus membranaceus), rosemary (Salvia rosmarinus) and mallow (Malva sylvestris). The effectiveness of three green synthesized nanoparticles in the adsorption of lead ions from a polluted water was studied under laboratory conditions. According to the results, the removal efficiencies of the copper oxide nanoparticles synthesized from astragalus (A-CuO-NPs), rosemary (R-CuO-NPs) and mallow leaf extract (M-CuO-NPs) especially at the highest initial concentration of Pb (1.5 mM) were 88.4 %, 84.9 % and 69.6 %, respectively. Most probably due the smooth morphology and more uniform configuration of the M-CuO-NPs, the changes between equilibrium adsorption (qe) and equilibrium concentration (Ce) were more regular than those of the A-CuO-NPs and R-CuO-NPs. Accordingly the best fitted data to Langmuir and Freundlich isotherms were observed in the adsorption of Pb onto the M-CuO-NPs. Despite the lowest removal efficiency of the M-CuO-NPs, with the equal volumes of each leaf extract and CuSO4.5H2O solution (20 mM), the most produced dry weight was observed for these nanoparticles (4.3 g per 100 mL of leaf extract). According to the results reported herein, the copper oxide nanoparticles synthesized from different plant covers are efficient adsorption agents for Pb from wastewaters.