Adsorption of Cr (VI), and Pb (II) from aqueous solution by 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide functionalized biomass Hazel Sterculia (Sterculia Foetida L.)

[Display omitted] •[BMIM] NTf2 functionalized Hazel Sterculia seed sorbent material synthesized.•After functionalization with ionic liquid, sorption capacity increased up to thrice.•(HS-IL) possessed sorption capacity of 82.88 mg/g (Cr-VI) and 108.63 mg/g (Pb-II)•Sorbent can be used to remove Pb (II) six and remove Cr (VI) three cycles.•More contaminants in aqueous streams are captured by IL functionalizedadsorbents. Biomass functionalization using a green solvent (ionic liquids-IL) is a new technology for water remediation. When sorbent materials are functionalized with green solvents or ionic liquids, the load of chemical separation methods is greatly reduced and recovery of ILs is facilitated. The purpose of this study is to determine the ability of an ionic liquid activated Hazel Sterculia foetida L. (HS) seed-based sorbent to remove Cr (VI) and Pb (II) from aqueous streams under enhanced ambient conditions. When compared to the raw HS, the IL functionalization of the adsorbent significantly improved the surface characteristics, i.e., increased surface area. Subsequently, the adsorption behavior of HS-IL was examined in detail for Cr (VI) and Pb (II), taking into account the effects of pH (2–10), contact time (0–300 min), speed (100–500 rpm), starting concentrations (10–100 mg/L), and temperature (303–323 K). Additionally, the adsorption processes of Cr (VI) and Pb (II) were fully evaluated using the Langmuir, Freundlich, Sips, and Toth two-and three-parameter models. When HS + IL was compared to HS (qm = 29.2 mg/g for Cr (VI); qm = 36.4 mg/g for Pb (II), the Langmuir isotherm model predicted a maximum adsorption capacity of qm = 82.9 mg/g (Cr(VI)); 108.63 mg/g (Pb (II)). Furthermore, kinetic modeling investigations demonstrated that the adsorption of Cr (VI), Pb (II) was better suited to a pseudo-second order model (R2 > 0.99). Moreover, the desorbing agents HCl and NaOH recovered the adsorbent (HS, HS-IL) from Cr (VI) and Pb (II) metal solutions, respectively. Finally, the reusability of the adsorbent (HS-IL) shows promise for Pb (II) up to six cycles and three Cr (VI) cycles.