Crown ether-functionalized hydrochars: Novel hybrid materials as potential adsorbents for copper and lead ions from water

Water pollution poses a major threat to environmental sustainability and human health. Here, we report novel 4 ' -aminobenzo-15-crown-5 ether-functionalized hydrochars as eco-friendly adsorbents for the removal of copper and lead ions from water. The hybrid materials were synthesized via a carbohydrate-assisted hydrothermal route using sucrose, starch, and fructose as carbon sources. Pristine and functionalized hydrochars were characterized by various techniques, including scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), thermal analysis (TG/DTG/DTA) and X-ray photoelectron spectroscopy (XPS). The crown ether functionalization and materials integrity were successfully confirmed. Batch adsorption measurements for Cu 2+ and Pb 2+ removal from aqueous solutions demonstrated that the Freundlich isotherm provided the best fit, suggesting multilayer and heterogeneous adsorption. The adsorption capacities ranged from 10.15 to 16.86 mg∙g -1 for Cu 2+ and from 8 to 11.93 mg∙g -1 for Pb 2+ , indicating their potential as sustainable materials for mitigating water pollution. • One-pot hydrothermal route affords crown ether-functionalized hydrochars. • Sucrose, starch and fructose were used with 4 ' -aminobenzo-15-crown-5 ether. • A comparative study of hydrochars was conducted. • Demonstrated Cu 2+ and Pb 2+ removal from aqueous solutions. • This approach can be extended to biomass and other amino-crown ethers.