Eco-Friendly Water Purification Using Copper-oxide Nanoparticles Enhanced with Neem Leaves for Heavy Metal Removal

Abstract

The method of using nanoparticles with plant extract to remove heavy metals from waste water has gain a lot of interest. Heavy metals have given rise to several problems not only to humans but also to plants and animals because of their extremely toxic effects. The aqueous waste streams generated from different industries such as manufacturing industries and agricultural industries generally contain high levels of heavy metal contamination. Copper oxide neem nanoparticle (CuONpNm) was utilized as low-cost adsorbents for the removal of Zn2+, Cu2+, Ni 2+ and Cd2+ ions from aqueous solution. The nanoparticles were prepared using copper sulphate. Batch adsorption methodology was used to evaluate the effects of solution pH, contact time and adsorbent dose, scanning electron microscope (SEM), Fourier transform infrared spectrophotometer (FTIR) and Transmission electron microscopy (TEM) were used to characterize the adsorbents. The equilibrium isotherm data were analyzed using the Langmuir and Freundlich isotherm models. The kinetic data were analyzed using the pseudo-first order and pseudo-second order equations. Maximum adsorption of CuONpNm on Zn2+, Cu2+, Ni 2+ and Cd2+ was 93.71 %, 90.93%, 89.92% and 83.91 % respectively at pH 6. The optimum conditions for adsorbent dose were determined at 0.1 g and 30 oC. The amount of metal uptake increased with contact time for all metal ions studied until equilibrium was reached. The Freundlich isotherm model provided the best fit to the experimental data for CuONpNm as indicated by the regression coefficient values (R2> 0.994). The pseudo-second order equation gave the best fit to the experimental data for all the metal ions (R2> 0.961).