One pot synthesis of CuS-PVA nanoparticles and fabrication of maize cob based nanocomposites for the removal of iron (III) ions from wastewater

Abstract

Copper sulfide nanoparticles capped with polyvinyl alcohol were synthesized and incorporated with activated maize cob to form PVA-CuS-MC nanocomposites. The nanocomposites were used to remove Fe(III) ions from wastewater solution through adsorption process. The optical properties of the synthesized nanoparticles showed two absorption peaks on the spectra of the uncapped CuS and PVA capped CuS nanoparticles that was red shifting when the capping molecule was introduced. TEM images of the nanoparticles showed spherical particles. The sizes decreased when the stabilizer (PVA) was introduced onto the surface of the copper sulfide nanoparticles from 3.57 ± 0.30 nm to 1.85 ± 0.511 nm, respectively. The XRD pattern of all the nanoparticles projected hexagonal phase structures. SEM micrograms of the activated maize cob showed an improve surface with many sites for bonding compared to the inactivated maize cob. PVA-CuS-MC nanocomposites also shows the distribution of nanoparticles onto the surface of an activated maize cob. Adsorption of Fe(III) ions onto maize cob and PVA-CuS-MC nanocomposites was investigated using ICP. An optimum pH of 4 was achieved and the equilibrium reached it maximum peak in 60 min. The discovered results showed that PVA-CuS-MC nanocomposite can be used as an alternative adsorbent as it displayed the highest adsorption capacity of 88.74 mg/g. Kinetics study showed that sorption of Fe(III) ions was achieved through more than one process. The equilibrium data fitness was also tested using Langmuir, Freundlich, and Sips isotherm models. Adsorption kinetics and isotherm accurately fitted the pseudo-second-order kinetic model and Sips isotherm model, respectively. Thermodynamic studies also confirmed that the adsorption was a spontaneous endothermic system. The obtained results proved that PVA-CuS-MC nanocomposite can be employed as an effective and inexpensive adsorbent for the removal of heavy metal ions such as Fe(III) ions from aqueous solutions compared to the conventional adsorbents.