Efficient and ultrafast removal of Cd(II) and Sm(III) from water by leaves of Cynara scolymus derived biochar

Abstract Applicability of biochar materials in water remediation is picking up recent interests on account of their sustainability and low mass-production cost. Herein, a novel ecofriendly nanobiochar was successfully fabricated by employing discarded materials from Cynara scolymus leaves (CSL) (Artichoke) as a green renewable low-cost nanosorbent. The produced nanomaterial was employed to estimate the adsorption characteristics towards two different heavy metal cations namely; cadmium and samarium using microwave sorption technique. The chemical composition and the surface morphology of the as-prepared nanobiochar (CSL-NanoB) were determined and fully characterized by (FT-IR, SEM, XRD , TGA and EDX) analyses, which proved the uniform nanosized biochar particles (23.54–27.8 nm). Microwave-assisted sorption technique as a rapid approach was utilized and implemented to assess the influences of some critical analytical parameters on adsorption process as solution pH, nanobiochar dose, irradiation exposure time, interfering ions and initial metal ion concentrations. The optimum conditions were quantitatively estimated at pH 7.0, 25 s heating time, and 10 mg nanosorbent mass. The equilibrium uptake capacity values of Cd(II) and Sm(III) were established as 1150 and 650 μmolg −1, respectively. Metal complexation with −OH and −COOH groups and ion exchange were characterized as the participating dominant mechanisms in adsorption process. Sorption kinetics data were fitted well with pseudo-first-order and Elovich with the contribution of intra-particle diffusion in the adsorption mechanism, as well as correlated with Freundlich isotherm model. Thermodynamic parameters indicated that, the sorption process of examined metal ions on CSL-NanoB was endothermic as favored at high temperature and spontaneous in nature. Furthermore, the adsorption performance of CSL-NanoB was significantly stable and efficient after multiple regeneration process. The outlined results indicate that, the investigated CSL-NanoB is a sustainable, dynamic and affordable nanosorbent to contribute in solving water pollution problems.