Purification and refining of mazut (fuel oil) is an absolutely essential and vital process, critically used worldwide to significantly reduce the severe environmental and operational challenges typically caused by its inherent impurities. This comprehensive study specifically focuses on a detailed comparative analysis of various different, newly developed, and environmentally friendly bio-composites that are being applied for effective mazut treatment through the process of adsorption, thereby providing a truly comprehensive evaluation of the most recent advances and innovations in bio-composite materials, alongside their novel preparation methods, and sophisticated adsorption mechanisms. In addition, crucial key factors critically affecting overall adsorption performance, such as specific surface area, pore structure, essential functional groups, and overall environmental compatibility, are thoroughly discussed. Moreover, this in-depth study meticulously examines the distinct advantages and inherent limitations of various promising bio-composites in terms of their practical efficiency, industrial scalability, and long-term sustainability. By effectively combining and seamlessly integrating the collective findings of numerous existing studies, The reviewed studies demonstrated that among environmentally friendly polymeric materials, chitosan- and nanocellulose-based composites are the most promising candidates for developing desulfurization adsorbents because of their abundant functional groups, tunable surface properties, and excellent environmental compatibility. Furthermore, among the adsorbents reviewed, biomass-derived activated carbon exhibited superior desulfurization performance owing to its high specific surface area, regeneration capability, and high adsorption efficiency toward sulfur-containing compounds. The important findings presented in this valuable review article ultimately aim to robustly support the critical advancement of green technologies in industrial waste management and crucial environmental protection efforts globally.