CO2 Reduction Rate of Photosynthetic Bacteria with Ceramics

To address global warming caused by increased CO2 emissions, many studies on CO2 reduction have been conducted worldwide. In carbon capture and storage (CCS) technology, the mineral carbonation process causes CO2 to react with particular metals or compounds to stably fix CO2. Many relevant studies have been performed on this capture process. Based on research describing photosynthetic bacteria that fix CO2 in the process of producing H2 under light irritation, this study combines ceramics with photosynthetic bacteria to develop a material capable of reducing environmental CO2. To investigate the possible combinations this study conducted experiments on ceramic materials of hardened cement pastes and lightweight aggregates made using waste from the Korean Y power plant. The photosynthetic bacteria Rhodopseudomonas pentothenatexigens AE8-5 was used and cultivated in a standard culturing medium. To examine the CO2 reduction rate, a 165 mL sealable glass bottle was used and CO2 was injected through the rubber lid using a syringe. Ceramic specimens were placed in the medium with the photosynthetic bacteria, and then were cultured in a shaking incubator at 25-30°C, a pH of 7, 6000 lux irradiation, and a shaking rate of 120 RPM. After the injection of the bacteria, gas chromatography-thermal conductivity detection analysis was performed on the gases in the bottles, and the presence of CO2 was confirmed. When 30 g of the ceramic aggregate with a low reaction rate with CO2 was used and the photosynthetic bacteria were irradiated, the CO2 concentration was reduced by ~40%. It is necessary to address the amount of ceramic material used and the shaking friction generated in order for uniform light irradiation when the ceramic is combined with photosynthetic bacteria. The results demonstrated that materials combining photosynthetic bacteria and ceramic are applicable for future studies.