Bio-inspired Nanobiochar Supported Composite for Enhanced Adsorption of Methylene Blue Dye

Abstract

Nanobiochar-based biopolymer composites were developed using Corn stalk residue was selected as the raw material for biochar preparation through pyrolysis at 350 °C, and the obtained biochar was further reduced to nanoscale particles via mechanical milling. The starch, cellulose, and chitosan used as supporting matrices for Nanobiochar-based biopolymer composites. The as prepared composites were utilized for the adsorption of 10mg/L methylene blue (MB) dye as adsorbent in aqueous solution of adsorbate loading 5 mg composite. The free radical graft polymerization technique was employed for the preparation of nanobiochar based biopolymer composites (Nanobiochar-Starch, Nanobiochar-Cellulose, and Nanobiochar-Chitosan). The size, structural, functional and morphological features were analyzed using ultraviolet–visible (UV–Vis) spectroscopy, fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Adsorption experiments were carried out with MB dye at pH 9.0 room temperature, with the concentration changes monitored at 665 nm for 140 minutes using UV–Vis spectrophotometer. Among the synthesized composites, Nanobiochar-Starch demonstrated the maximum removal efficiency (~85%), followed by Nanobiochar-Cellulose (~70%) and Nanobiochar-Chitosan (~63%). The adsorption mechanism was consistent with a pseudo-second-order kinetic model with correlation coefficient (R²) equal to 0.7735, 0.6974 and 0.6405 for NB-Starch, NB-Cellulose and NB-Chitosan Composite.