adsorptive removal of crystal violet dye using biochar synthesised from agriculture residue: a sustainable study

In recent years, there has been a growing interest in eliminating pollutants from aqueous solutions through adsorption onto carbonaceous materials. rice straw biochar (rcb) and sugarcane bagasse biochar (scb) were evaluated as adsorbents for removing crystal violet (cv) dye from aqueous solutions. ph (1–12), adsorbent dosage (0.1–0.5 g/l), cv concentration (10–50 mg/l), and contact time (30–150 min) were varied at room temperature to obtain the optimum condition. the maximum monolayer adsorption capacities of 476.2 and 161.29 mg/g for scb and rcb, respectively were obtained at optimum condition. the adsorption equilibria fitted best to the freundlich isotherm model (r2 = 0.9985), and the kinetics followed a pseudo-second-order model (r2 = 0.9907), indicating chemisorption and monolayer coverage. under these conditions, crystal violet dye removal efficiencies exceeded 90% for both biochars. these results demonstrate the high potential of rcb and scb as low-cost bioadsorbents for effective cv dye removal in the wastewater treatment.