Preconcentration of heavy metal ions using Konjac gum-Co3O4 magnetic hydrogel prior to their determination by ICP-OES

In this study, a hydrogel embedded with magnetic cobalt nanoparticles was synthesized from natural Konjac gum through a simple and low-cost method and its potential for separation and preconcentration of lead, copper, zinc, chromium, cobalt, and cadmium ions was investigated. Determination of the extracted metal ions was carried out using inductively coupled plasma /optical emission spectroscopy. The magnetic property of the hydrogel helps the separation from the solution and improves the adsorption capacity. The proper synthesis of the magnetic hydrogel was confirmed with different characterizations techniques, such as Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The effective parameters on the sorbent synthesis and extraction process were studied. Under optimized conditions, the linear range and detection limit were found to be 0.3–100.0 µg L⁻¹ and 34.0 ng L⁻¹ for lead, 0.1–100.0 µg L⁻¹ and 17.0 ng L⁻¹ for chromium, 0.07–100.0 µg L⁻¹ and 10.0 ng L⁻¹ for zinc, 0.07–100.0 µg L⁻¹ and 12.0 ng L⁻¹ for copper, 0.1–100.0 µg L⁻¹ and 15.0 ng L⁻¹ for cadmium and 0.1–100.0 µg L⁻¹ and 21.0 ng L⁻¹ for cobalt, respectively. The developed method was successfully employed for the analysis of the above ions in the real samples including water, fruit and soil.