Synthesis, characterization, and application of oxidant-modified biochar prepared from sawdust for sequestration of basic fuchsin: isotherm, kinetics, and toxicity studies

Waste recycling and up-cycling strategies are important for the sustainability of resources on earth, as water is the key to the sustenance of life. In the present study, oxidant-modified biochar (OBC) is used for the adsorptive removal of basic fuchsin from aqueous systems. Characterization of the adsorbent was done using various analytical techniques. Morphological analysis shows that OBC was irregular in shape with a spongier structure. The adsorbent is thermally stable until 850 °C. Functional groups on OBC before and after adsorption were determined using Raman spectroscopy and FTIR. Through batch investigations, the effect of different experimental factors on the adsorption process, such as pH, biosorbent dosage, and initial concentration of pollutant, were optimized. The highest removal efficiency of 98.28% was seen at pH 6.0 with 0.05 g adsorbent dosage at the initial pollutant concentration of 10 mg/L. Freundlich isotherm and pseudo-second-order kinetics model fits to the adsorption process. The toxicity of basic fuchsin before and after adsorption was compared by exposing Vigna radiata seeds to the dye. The growth inhibition reduced to 26.86% from 67.67% after the adsorption process. Thus, oxidant-modified Biochar was effective in the adsorptive removal of basic fuchsin from water.