Au(III) Extraction from Water Samples Using Triazole-Coated Novel Magnetic Adsorbents and Analysis by Inductively Coupled Plasma-Optical Emission Spectroscopy.

Abstract

In the present investigation, the synthesis, characterization, and application of triazole-coated novel magnetic nanoparticles (MNPs) are systematically carried out, focusing on their efficacy as adsorbents for extracting Au(III) ions. The synthesis process involves the sequential coating of magnetite nanoparticles with tetraethylorthosilicate (SiO₂), 3-chloropropyltriethoxysilane (CPTES), and 3,5-diamino-1,2,4-triazole (DAT). The MNPs synthesized at each stage are analyzed using high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric and differential thermal analysis (DT/TGA) to confirm the successful coating of the desired adsorbent. Fe₃O₄@SiO₂@CPTES@DAT MNPs selectively recover Au(III) ions under optimum conditions of pH = 2, 10 mg adsorbent amount, and 20 min contact time, and quantification of Au(III) ions is carried out by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The method's suitability to adsorption isotherm and kinetic models is examined and found to be more compatible with the Freundlich isotherm and pseudo-second-order kinetic model. Relative standard deviation, limit of detection, and limit of quantification are calculated as 2.51%, 0.019, and 0.065 μg L^-1, respectively, as analytical performance parameters. Several water samples are tested for Au(III) concentration using the optimized method.