Efficient solid-phase extraction of Pb2+, Cd2+, and Cr3+ using ionic liquid-based bis(trifluoromethylsulfonyl)imide grafted onto silica gel as a novel sorbent

Abstract

In this study, we developed the modification of silica gel through physical interaction with 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and N-alkylpyridinium bis(trifluoromethylsulfonyl)imide, resulting in the creation of four solid-phase agents (NDL1-SiO2 to NDL4-SiO2). These agents were utilized for the adsorption of three metallic ions (Cr3+, Cd2+, and Pb2+). Subsequently, the ionic liquids were successfully grafted onto silica gels, and their structure and morphology were characterized by Fourier Transform Infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX). Among the various materials synthesized, NDL1-SiO2 exhibited the highest adsorption efficiency, with an enrichment factor of 150. The influence of various parameters on the recovery process was carefully investigated, and at pH 8.5, the recoveries for Cr3+, Cd2+, and Pb2+ were obtained at 95.6 %, 77.5 %, and 96.5 %, respectively. The method demonstrated high sensitivity, with detection limits for Cr3+, Cd2+, and Pb2+ ions measured at 0.028, 0.032, and 0.132 μg L−1, respectively. Overall, our findings emphasize the potential of the developed solid-phase extraction method using the ionic liquid-modified silica gel-based sorbent. This approach offers a greener and more efficient means of enriching metal ions in environmental analysis.