Functionalized biochar derived from novel <i>Neolamarchia cadamba</i> leaf extracts for the adsorption of Congo Red dye: kinetics, optimization, and reusability studies

ABSTRACT The present research emphasized on the removal of Congo Red (CR) dye from aqueous solutions using an adsorbent synthesized by utilizing the leaf extract of Neolamarchia cadamba as a bio-template. This facilitates the formation of zinc oxide nanoparticles which are then carbonized to enhance adsorption capabilities. This synthesized material is referred to as NC@ZnC, for coherent adsorption of CR dye. Various operating parameters were used for the adsorption of CR onto NC@ZnC. The maximum monolayer decontamination of CR dye was 303.03 mg/g when it was incubated for 90 min at a pH of 5. The specific surface area of amalgamated NC@ZnC was reported to be 6.509 m2/g using Bruaneur–Emmett–Teller analysis. Field-emission scanning electron microscopy was used to show the rough surface area, X-ray diffraction analysis was used to determine the crystalline structure of the adsorbent with a grain size of 20.062 nm. Elemental dispersive X-ray analysis was used to determine the elemental composition of NC@ZnC. Raman spectroscopy demonstrates a lysine group that, upon adsorption, interacts with oxygen to form a bond. NC@ZnC regresses pseudo-second-order kinetics and follows the Langmuir isotherm for the adsorption process. The sorption activity with respect to temperature appears to be displaying +ΔH° and +ΔS°, which suggests an endothermic and impulsive nature.