Synthesis and application of a novel magnetic SBA-15 nanosorbent for heavy metal removal from aqueous solutions

In this work for the first time, magnetic nanoporous SBA-15 functionalized with isatin groups as a magnetic nanosorbent was applied for the simultaneous extraction of trace amounts of cadmium(II), nickel(II), lead(II), and zinc(II). The characterization of this nanosorbent was studied using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The effect of several factors such as pH, amount of sorbent, extraction time, type and volume of the eluent, sample volume, sorption capacity, and potentially interfering ions were investigated. In the selected conditions, it was observed that the limits of detection were 0.10 ng mL⁻¹ for Cd(II), 0.25 ng mL⁻¹ for Ni(II), 0.4 ng mL⁻¹ for Pb(II), and 0.2 ng mL⁻¹ for Zn(II), and the maximum sorption capacity of this suggested magnetic nanosorbent was 140, 122, 110, and 115 mg g⁻¹ for Cd(II), Ni(II), Pb(II), and Zn(II), respectively. Finally, the suggested procedure was applied for determination of cadmium(II), nickel(II), lead(II), and zinc(II) at trace levels in different water and agricultural products with satisfactory results.