Effect of pyrolysis temperature of domestic sewage sludge biochar on CO2 adsorption

Climate change is a global challenge driven by increasing greenhouse gas (GHG) concentrations, particularly carbon dioxide (CO 2 ). Carbon capture and storage (CCS) technologies, especially adsorption-based methods, have emerged as promising mitigation strategies. Biochar, a carbon-rich material produced through pyrolysis under oxygen-limited conditions, has gained attention due to its high porosity, favorable surface chemistry, and cost-effectiveness. This study investigates the CO 2 adsorption potential of biochar derived from domestic sewage sludge at the Keputih Surabaya Septage Treatment Plant under different pyrolysis temperatures (300 ∘ C, 450 ∘ C, and 600 ∘ C). Biochar samples were produced at varying temperatures and characterized based on the surface area, pore structure, elemental composition, and alkalinity. CO 2 adsorption capacity was evaluated to determine the influence of the pyrolysis conditions on the biochar performance. The findings indicate that the pyrolysis temperature significantly affects the biochar characteristics. Biochar produced at 600 ∘ C exhibited the highest CO 2 adsorption capacity of 0.971 mmol/g due to its enhanced porosity and alkalinity. This study highlights the potential of sewage sludge biochar for CO 2 capture while promoting sustainable waste management. Further research is recommended to increase the CO 2 adsorption capacity through chemical activation. With this approach, the subsequent study contributed more significantly to the development of biochar as a more effective and sustainable solution for climate change mitigation. • Sludge waste from Keputih Surabaya is underutilized and often used as an unprocessed fertilizer. • Pyrolysis at 600 ∘ C yields biochar with the highest CO 2 absorption capacity (0.971 mmol/g). • Research on biochar production from the Keputih Surabaya sludge can mitigate environmental risks.