Regarding wastewater treatment, an important aspect is the removal of organic pollutants to reduce environmental impact and comply with discharge regulations. This thesis focuses on the adsorption of a cationic dye, Methylene Blue (MB), using sustainable innovative materials. The studied adsorbent materials include biochar and hydrochar of organic origin, as well as activated carbon as a reference. The main objective is to evaluate their effectiveness and to understand the key factors influencing the adsorption process, while also modelling it. Biochar was produced from rice husk through slow pyrolysis at 600 °C with 15 °C/min, using both N2 and CO2 as inert gases, leading to two different biochars (biochar N2 and biochar CO2).