Micro-structure, surface properties and adsorption capacity of ball-milled cellulosic biomass derived biochar based mineral composites synthesized via carbon-bed pyrolysis

Abstract Given the increase in global threats to the environment and the growth in energy demand, there is great interest in developing renewable and green biochar-based materials. This article investigated ball-milled cellulosic biochar-based composites incorporating minerals (montmorillonite, calcite, or quartz) synthesized by an in situ carbon-bed pyrolysis method. The synthesized samples were examined using X-ray powder diffraction (XRD), scanning and transmission electron microscopy (SEM, TEM), N2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy (FTIR), thermogravimetry-differential thermal analysis (TG-DTA), Raman spectroscopy, and organic dyes adsorption analysis. It was shown that the mineral components incorporated during ball-milling modified the microstructure, morphology, and surface properties of biochar composites. Synergistic effects of oxygen functional groups and mesoporous layered structure contributed to the functionalization and surface modification of biochar-based montmorillonite composites, as reflected by a remarkably enhanced adsorption performance of organic dyes. Freundlich isotherm and pseudo-second-order kinetic models were found to provide an accurate description of the chemical adsorption of MB onto the heterogeneous surface of the biochar-based montmorillonite composite via cation exchange.