Adsorption of dyes and a colorant using biochar is an emerging technology with environment-friendly and cost-effective applications. In this study, we investigated the adsorption isotherms of Brilliant Blue (BB) and Congo Red (RR) using Biochars prepared from regional plant waste of the Musa acuminata stem at 450⁰C (BSB 450). A batch experiment study for BB and CR with its initial concentration (1-240 mg/l) contact time (30—240 min) pH (3-10) and dose range (25-450 mg/l) at temperature 303K was carried out.  The experimental data follows the Freundlich isotherm for BB and Langmuir isotherm for CR. As per our results adsorption isotherm equilibrium data shows the highest adsorption of BB onto BSB 450 is 175.57 mg/g and CR is 135.15 mg/g in Dubinin–Radushkevich model. The study also shows that BSB 450 is a cost-effective and environment-friendly adsorbent that was used for the treatment of dyes containing effluents like a tannery, textile, and dye waste producing industries.