In a study published in Results in Engineering, Oktaviana et al., explore biochar’s ability to capture carbon dioxide (CO2), a major contributor to climate change. The research specifically investigates how the temperature at which biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More is produced (pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More temperature) affects its capacity to adsorb CO2.  

Climate change, driven by increasing concentrations of greenhouse gases like CO2, is a critical global challenge. To address this, scientists are exploring various mitigation strategies, including carbon capture and storage (CCS) technologies. Adsorption, a process where CO2 molecules bind to a material’s surface, is a promising method within CCS.   Biochar has emerged as a potential adsorbent. Its porous structure, favorable surface chemistry, and cost-effectiveness make it attractive for CO2 capture. Biochar can be derived from various sources, including agricultural residues and, as this study explores, sewage sludge.  

This research focuses on biochar derived from domestic sludge waste at the Keputih Surabaya Septage Treatment Plant. The domestic sludge samples contained moisture, which needed to be reduced before further processing. The study examines how different pyrolysis temperatures (300°C, 450°C, and 600°C) affect its ability to capture CO2. The study found that pyrolysis temperature significantly influences biochar’s characteristics, including its pore structure, surface area, and chemical composition.  

The study’s key finding is that biochar produced at 600°C demonstrates the highest CO2 adsorption capacity (0.971 mmol/g). This enhanced adsorption is attributed to the biochar’s increased porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More and alkalinity at higher pyrolysis temperatures.  

This research suggests that biochar derived from sewage sludge can be a viable material for CO2 capture, offering a sustainable waste management solution. However, the authors recommend further research to enhance biochar’s CO2 adsorption capacity, potentially through chemical activation methods.  

Source: Oktaviana, A. A., Hermana, J., Syafei, A. D., & Hsi, H. C. (2025). Effect of Pyrolysis Temperature of Domestic Sewage Sludge Biochar on CO2 Adsorption. Results in Engineering, 105136.