Application of a chitosan bimetallic nanocomposite for the simultaneous removal of cadmium, nickel, and lead from aqueous solution

Abstract

Wastewaters often consist of heavy metals and the use of iron-based bimetallic nanocomposites to remove these inorganic pollutants is still unclear. This investigation used a chitosan-iron/ silver bimetallic nanocomposites (CS-Fe/AgNPs) to eliminate cadmium (Cd2+), nickel (Ni2+), and lead (Pb2+) from aqueous solution. The chemically synthesized CS-Fe/AgNPs were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transformed infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction, and thermogravimetric analysis, which confirmed the shape, size, and composition of the bimetallic nanocomposite synthesized. The kinetics, adsorption isotherms, and thermodynamics of Cd2+, Pb2+, and Ni2+ were also studied in batch experiments. Analysis of inductively coupled plasma-optical emission spectroscopy was employed to quantify the amount of Cd2+, Pb2+, and Ni2+ absorbed by the CS-Fe/AgNPs from an aqueous solution. The results obtained revealed that Pb2+, Cd2+, and Ni2+ adsorption capacities using CS-Fe/AgNPs under optimized conditions were 2.01 mg g–1 for Pb2+, 1.73 mg g–1 for Cd2+, and 1.81 mg g–1 for Ni2+, respectively. These results showed that the application of CS-Fe/Ag bimetallic nanocomposite can be applied to remove these heavy metals from wastewaters, simultaneously under optimized conditions such as effects of pH, contact time, and adsorbent dosage.