Biochar production from palm kernel shell, coffee husk and bovine rumen content via pyrolysis and its use in the removal of methylene blue from aqueous solution

Introduction: The large amount of residual biomass derived from agricultural activity is an ongoing environmental issue that requires efficient strategies to transform these biowastes into value-added products within the framework of responsible production and consumption. Objective: In this study, biochar was produced by pyrolysis of a mixture of palm kernel shell (40%), coffee husk (40%), and bovine rumen content (20%) to evaluate its capacity to remove methylene blue from aqueous solution. Materials and Methods: The pyrolysis was carried out at a temperature of 750 degrees C, with a heating rate of 15 degrees C/min, for 2 h. The pyrolysis product, namely biochar FT-750, was characterized in terms of its elemental composition, ash content, and surface area. The biochar FT-750 was evaluated as adsorbent of methylene blue from aqueous solution (250 mg/L) at different pH values (2-10). Results and Discussion: The FT-750 biochar had a carbon content of 73.6%, an ash content of 16.1%, and a surface area of 0.88 m(2)/g. With these characteristics, a methylene blue removal of 37% (53.9 mg/g) was achieved at pH 10. The results from the adsorption process were correlated with the pseudo-first-order kinetic model and Freundlich isotherm. Conclusions: Pyrolysis is an effective strategy for the transformation of palm kernel shell, coffee husk, and bovine rumen content into a value-added biochar useful for the removal of contaminants from aqueous solutions.