Fabrication of nanocomposite based on oxidized biochar and oxidized cellulose nanofibers and its potential cd(II) adsorption

Abstract Herein, the oxidized biochar (OBC) derived from rice straw was prepared and homogeneously embedded into TEMPO-mediated oxidized cellulose nanofiber (TOCNF). The resulting colloidal suspension, when mixed with OBC and crosslinked via ionic interaction using branched polyethyleneimine, forms nanocomposites with promising potential. The characterization of these composites, including SEM, EDX, surface morphology, and spatial elemental composition, reveals their unique properties. The effect of adding OBC to TOCNF at different ratios is estimated by surface area analysis following the BET and BJH methods. The adsorption settings for the as-formed composites were investigated to optimize the adsorption effectiveness of the fabricated sorbents. These conditions included contact time, Cd(II) concentration, pH, and sorbent dosage. With greater adsorption effectiveness of 70% and 90% at 1 h and 2 h, the nanocomposite with an equal ratio of OBC and TOCNF was discovered to be a valuable sorbent for Cd(II) elimination (0.15 g of BCC3 composite in 50 mL of 100 mg/L Cd(II) at pH 7.0). The adsorption process was modeled using kinetic and isotherm models. The correlation coefficients for the pseudo-first and second-order kinetics are similar and closest to 1.0 based on the data. Thus, Cd(II) adsorption may involve both physio-sorption and chime-sorption. Additionally, the linear fitting of the Freundlich isotherm model demonstrated a heterogeneous and multilayer surface interaction with the greatest adsorption capability of 44 mg/g. Suggesting potential applications in environmental engineering and materials science.