Using response surface methodology, the researchers established predictive regression models that identified optimal operating conditions, achieving a maximum specific surface area of 1,156.37 m²/g and a minimum mesoporosity of 39.29%.
The global shift toward low-carbon energy systems has increased interest in renewable biomass as alternatives to fossil fuels. Sugarcane bagasse, a major by-product of the sugar industry produced in vast quantities each year, is often burned or landfilled, creating environmental burdens and wasting valuable resources. Pyrolysis provides a promising pathway to convert this biomass into biochar, a porous carbon material used in pollutant adsorption, wastewater treatment, soil remediation, and energy storage. Compared with conventional electric heating, microwave-assisted pyrolysis enables rapid, volumetric heating and higher efficiency. However, interactions among temperature, activating agents such as KOH, and CO₂ atmosphere complicate pore control, highlighting the need for systematic optimization.
A study (DOI: 10.48130/scm-0025-0014) published in Sustainable Carbon Materials on 20 January 2026 by Wenke Zhao’s team, Harbin Institute of Technology, provides a statistically optimized and experimentally validated framework for transforming agricultural waste into high-performance porous carbon materials with tunable structure for environmental and energy applications.
The researchers integrated controlled microwave-assisted pyrolysis experiments, detailed structural characterization, and advanced statistical modeling to systematically investigate how pyrolysis temperature, KOH addition, and CO₂ flow rate affect sugarcane bagasse–derived biochar. A dedicated microwave pyrolysis system was constructed with precise temperature monitoring and gas flow regulation, and pretreated bagasse powder was subjected to varying operational conditions. Scanning electron microscopy (SEM) was first employed to track morphological evolution, revealing that increasing temperature initially enhanced pore formation, but excessive heating led to micropore collapse and structural degradation. Nitrogen adsorption–desorption isotherms and BET analysis quantified these structural changes, showing that specific surface area rose from low values at 700 °C to a peak near 800 °C before declining at 900 °C due to pore coalescence and wall thinning. When CO₂ flow rate was varied, higher flow intensified secondary gasification reactions, reducing biochar yield from above 30 wt.% to below 20 wt.% while simultaneously promoting pore restructuring and increasing specific surface area, shifting the structure from mesopore-dominated to more microporous frameworks. To capture the combined and interactive effects of the three factors, the team applied a three-factor Box–Behnken design within a response surface methodology (RSM) framework. Quadratic regression models for specific surface area, mesoporosity, and yield demonstrated strong predictive performance, with adjusted R² values exceeding 0.98. The models ranked the relative influence of factors as KOH addition > CO₂ flow rate > pyrolysis temperature. Response surface analysis identified optimal conditions—approximately 803 °C, 64.5 g KOH, and ~68 ccm CO₂—under which the biochar achieved a maximum specific surface area of 1,156.37 m²/g, closely matching predictions, while a minimum mesoporosity of 39.29% was obtained under slightly adjusted conditions. Overall, the results highlight precise microwave parameter control as a powerful strategy for tailoring pore architecture, albeit with a clear trade-off between maximizing surface area and maintaining char yield.
In summary, this study establishes a robust statistical and experimental framework for optimizing microwave-assisted pyrolysis of sugarcane bagasse, quantitatively ranking the influence of key process variables and validating predictive models for surface area, porosity, and yield. By demonstrating how agricultural waste can be transformed into precisely engineered porous carbon materials, the study provides both theoretical insight and practical guidance for sustainable biomass valorization, supporting applications ranging from pollutant adsorption to advanced energy storage systems.
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References
DOI
10.48130/scm-0025-0014
Original Souce URL
https://doi.org/10.48130/scm-0025-0014
Funding information
The authors are grateful for the financial support from the National Natural Science Foundation of China (Grant Nos 52506009, 52076049), Heilongjiang Province 'Double First-class' Discipline Collaborative Innovation Achievement Project (Grant No. LJGXCG2023-080), Heilongjiang Provincial Key R&D Program 'Unveiling the Leader' Project (Grant No. 2023ZXJ02C04), and the Postdoctoral Fund in Heilongjiang Province (Grant No. LBH-Z22115).
About Sustainable Carbon Materials
Sustainable Carbon Materials is a multidisciplinary platform for communicating advances in fundamental and applied research on carbon-based materials. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon materials around the world to deliver findings from this rapidly expanding field of science. It is a peer-reviewed, open-access journal that publishes review, original research, invited review, rapid report, perspective, commentary and correspondence papers.