Removal of toxic dye from dye-laden wastewater using a new nanocomposite material: Isotherm, kinetics and adsorption mechanism

In this study, (hemi)cellulosic biochar-based environment-friendly non-toxic nanocomposite ( n Ag-AC) was fabricated for an inordinate overlook of toxic dye-laden wastewater depollution. This hybrid nanocomposite grafted with silver nanoparticles, numerous hydroxyl and π-bond containing functional groups exhibited outstanding physicochemical properties. FESEM images indicated the heterogeneous porous structure of n Ag-AC, while BET analysis revealed mesoporous property with a significant increment of overall surface area (132%). Imbedding of silver nanoparticles and the presence of multiple hydroxyl groups was evident from the XRD and XPS spectrum. Further, the TGA result indicated excellent thermal stability, and FTIR analysis suggested the involvement of surface functional groups like –OH, =C = O, =NH, =C = C = , and –CH in Rhodamine B (RhB) adsorption. The adsorbent matrix provided the overall mechanical strength and facilitated recycling, while the functional matrix (biochar) provided the adsorptive locus for augmented RhB adsorption efficiency (92.77%). Experiments pertaining to adsorption isotherms and kinetics modeling suggested that RhB was removed through multilayer chemisorption on the heterogeneous n Ag-AC surface. The main RhB adsorption mechanism included cumulative efforts of H-bindings, π-π stacking interaction, pore-filling, and electrostatic interactions. The n Ag-AC maintained mechanical robustness with significant RhB adsorption even after three consecutive regeneration cycles signifying facile recycling. The n Ag-AC displayed an outstanding efficacy for the real industrial wastewater depollution, indicating high effectiveness for practical environmental applications. Finally, the cost analysis (incorporating economic, environmental, and social dimensions) suggested a significant role of the n Ag-AC in promoting and establishing sustainable development with the circular economy. • n Ag-AC showed excellent RhB removal efficiency and adsorption capacity of 46.38 mg g −1 . • RhB removal involves π-π stacking, pore-filling and electrostatic interaction. • -OH, =C = O, =NH, =C = C = , –CH groups are actively involved in RhB adsorption. • RhB adsorption was multi-layered chemisorption onto heterogeneous n Ag-AC surface. • The nAg-AC promotes environmental sustainability through a circular economic approach.