Ferro-aluminosilicate composite generated from coal gasification fine slag for the preconcentration and adsorptive removal of selected artificial sweeteners from water

This study explores the beneficiation of coal waste, particularly transforming coal gasification fine slag (CGFS) into advanced nanomaterials with unique properties for water decontamination as a pivotal step towards achieving the United Nations Sustainable Development Goal 6. Furthermore, converting CGFS into functional adsorbents aligns seamlessly with the principles of a circular economy, emphasising resource reutilization and sustainability. This work presents the development of ferro-aluminosilicate nanocomposites derived from CGFS. The nanocomposite was used as a new sorbent for the removal and magnetic solid-phase extraction (MSPE) of acesulfame (ACS), sucralose (SCL), and aspartame (ASP) from environmental water samples. Integrating MSPE with high-performance liquid chromatography equipped with a diode array detector (HPLC-DAD) facilitated highly sensitive detection and quantification of these compounds in diverse water matrices. The method achieved detection limits (LODs) ranging from 0.015 to 0.11 μg/L and quantification limits (LOQs) between 0.04 and 0.15 μg/L across ultrapure, tap, and river water samples, with linear dynamic ranges extending up to 650 μg/L and correlation coefficients exceeding 0.99. The mesoporous Fe₂O₃-Al₂O₃-SiO₂ nanocomposite demonstrated impressive adsorption capacities 88.5 mg/g for ACS, 80.0 mg/g for ASP, and 62.1 mg/g for SCL. Kinetic and isotherm analyses indicated that chemisorption governed the adsorption process, while thermodynamic evaluations confirmed that removal was spontaneous and endothermic. Application to river and wastewater samples yielded 81.4 % and 100 % removal efficiencies. The method also exhibited excellent recovery rates (83–102 %) with relative standard deviations below 5 %, underscoring its robustness and suitability for real-world water analysis.