Transformative strategies for heavy metals extraction: Ionic liquid-boosted fizzy capsule for distributive solid-phase microextraction in aquatic environments

Within this work, an innovative ionic liquid-coated sulphonyl silanized graphene oxide-supported fizzy capsule-enhanced ionic liquid distributive solid-phase micro-extraction (MGO@SO₃H-IL-DSPM) was successfully prepared for enriching and extracting lead [Pb(II)], cadmium [Cd(II)], and cobalt [Co(II)] ions from water samples. The MGO@SO₃H hybrid was investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), Zeta potential and surface area. Exploration and optimization were conducted on various parameters including solution pH, dosages of extractant, volume of ionic liquid, and the type and concentration of eluent. The optimized experimental conditions for achieving high extraction efficiencies of the targeted metals were determined as follows: a mixture of Na₂CO₃ and NaH₂PO₄ (0.12 g) each, at a 1:1 M ratio); utilization of 0.03 g of MGO@SO₃H nanocomposites; addition of 10 μL of ionic liquid as the extractant; pH adjustment to approximately 5 for Pb(II), and 4.18 for both Co(II) and Cd(II); and elution using HNO₃ as the eluent (at a concentration of 1.5 M, with a volume of 3 ml). Under the ideal circumstances, the extraction yield efficiencies of the target metal ions in four authentic water samples were in the range (96.09 % − 100 %) for Cd(II), (99.99 % − 102 %) for Pb(II), and (99.99 % − 103 %) for Co(II), the RSDs were lower than 1.7 %. The content of Cd(II), Pb(II), and Co(II) ions in four actual samples of water were determined within the range of 1.25 – 3.75 μg/L, 6 – 15 μg/L, and 29.15 – 70 μg/L, respectively.