Cyclic stability evaluation of a novel CO2 absorption-microalgae conversion (CAMC) system

CO2 absorption-microalgae conversion (CAMC) system is a promising alternative to simultaneous CO2 capture and utilization. However, it is necessary to explore the stability of recycled absorption solvent for subsequent culture of CAMC system. In this work, dilution, activated carbon adsorption and H2O2/UV photocatalytic treatment were used to treat the absorption solution that had been run once in CAMC system and then the subsequent culture was performed and its performance was evaluated. It was found that these treatments could restore the performance of circulating absorption solution and H2O2/UV photocatalytic treatment showed the best effect. The biomass concentration, NADPH content and RubisCO enzyme activities increased by 18 %, 92.0 %, and 26.5 % by H2O2/UV photocatalytic treatment. H2O2/UV photocatalytic treatment enhanced carbon fixation rate, which was 7.05 % higher than untreated group. H2O2/UV photocatalytic treatment could improve the yield of lipid and protein. These results showed that H2O2/UV photocatalytic treatment could restore the performance of circulating solution to the level of primary culture and maintain the cyclic stability of CAMC system. Therefore, this study provided a certain guiding significance for the application of CAMC system.