Sustainable conversion of bagasse into porous carbon using industrial excess heat and steam: Syrup decolorization and techno-economic analysis

The novelty of this work lies in its integrated approach, leveraging agricultural residues and optimizing energy efficiency by re-utilizing excess heat and steam from the sugar industry and enabling the process to be seamlessly integrated into existing industrial operations. The sustainable conversion of bagasse and filter cake into high-performance porous carbon for syrup decolorization was investigated. Porous carbons were synthesized through carbonization at 500 °C using industrial excess heat, followed by steam activation at 700-900 °C utilizing excess boiler steam. Bagasse-derived carbon activated at 900 °C (BA900) showed a surface area of 366.32 m 2 /g, a pore volume of 0.105 cm 3 /g, and 39% decolorization efficiency at 1.0 g sample weight. Although less efficient than commercial resins (72%), BA900 offers a sustainable, cost-effective alternative using renewable feedstocks and waste energy. Activated carbons from filter cake (FA900) and bagasse-filter cake composite (CA900) showed lower decolorization efficiencies due to heterogeneous composition and irregular pores. Economic analysis showed the process's feasibility with a net present value of $550,742, a return on investment of 494%, and a 0.16-year payback period, highlighting its low cost and rapid return. BA900 may serve as a pre-adsorption material, reducing resin load, extending service life, and lowering operational costs. Combining BA900 with resin provides a sustainable, cost-effective solution for syrup decolorization while utilizing waste energy from sugar production, serving as a model for enhancing industrial efficiency and sustainability. • Porous carbon is made from residue from sugar processing, recycling heat and steam. • Porous carbon derived from bagasse, improving its suitability for syrup adsorption applications. • Porous carbon demonstrated the feasibility of using in conjunction with commercial resin. • The net present value (NPV) and a return on investment (ROI) with a payback period of less than one year.