Refuse derived fuel char as a low-cost adsorbent for the cationic dye methylene blue

This work addresses the application of Refuse Derived Fuel (RDF) char as a low-cost adsorbent for methylene blue (MB) in batch mode, as an approach to remediate pigment contaminated effluents and a model for the adsorption of cationic analytes. The RDF char was tested without pre-treatment and after a cold alkali treatment to enhance adsorption. The adsorbents were characterized for proximate and ultimate composition, pH_pzc and N₂ adsorption/desorption behavior. Operation parameters such as pH, adsorbent dose, contact time, dye concentration and temperature were varied. Kinetic studies revealed that adsorption of methylene blue in the RDF chars followed a pseudo-second-order kinetic model. Adsorption isotherms showed differences in the possible adsorption mechanisms as a result of char activation. This work highlighted that RDF chars that are not suitable for energy conversion may be valorized as a low-cost adsorbents.