Efficient Removal of Cationic and Anionic Dyes Using HCl-Activated Biochar from Pine Waste: Adsorption Behavior and Thermodynamic Insights

In this work, the Pines plant, a cheap agricultural waste, is used in a batch manner to remediate synthetic wastewater that contains dyes. A cationic and anionic dye that is frequently used in the textile industry, Reactive red120 (RR-120), and disperse blue 79(DB-79) was employed to create the simulated wastewater. Biochar from pine plants treated with HCl (BC-HCl) was utilized. X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) were used to investigate and characterize the activated carbon. Morphological investigations revealed multiple layers with extremely porous surfaces, particularly following acid-induced carbon activation. Analysis was done on the equilibrium for the adsorption of Reactive red120 (RR-120), and disperse blue 79(DB-79) onto waste BC-HC. The BC-HC was made by impregnating hydrochloric acid into dried Pines plant biochar, then carbonizing and activating it at 300 °C. The findings demonstrated that when the initial, Reactive red120 (RR-120), and dispersed blue 79(DB-79) concentration, adsorbent dosage, and solution temperature rose, so did the dyes elimination. The Langmuir, and Freundlich, isotherms were used to examine the equilibrium data. The Freundlich isotherm best-fitted the adsorption, resulting in a maximum adsorption capacity of 90.211 mg g-1 , 92.23 mg g-1 at 25 °C for Reactive red120 (RR-120), and dispersed blue 79(DB-79). Based on thermodynamic investigations, the adsorption mechanism was proposed to be the presence of intra-particle diffusion with additional rate-controlling processes, with the process being spontaneous and endothermic.