Functionalized hydrogel for efficient CO2 capture and biorefinery to produce volatile fatty acids

CO2 capture and storage (CCS) is an effective way to solve the problem of high CO2 emissions caused by large-scale use of fossil energy. Conventional CCS processes usually employ ethanolamine to store and produces toxicants during high-temperature regeneration. Here a functionalized hydrogel (FMI) consisting of Pluronic F127 by crosslinking imidazolidinyl urea (IU) was prepared. The incorporation of IU enhanced the FMI affinity for CO2 by introducing a considerable number of N-H bonds. The formation of hydrogen bonds facilitated the sequestration of CO2 and improved the stability and plasticization resistance of the FMI. Meanwhile, a production blueprint was presented for converting captured CO2 to volatile fatty acids (VFAs) by microbial refining. The addition of Pt/Fe2O3 into biorefinery promoted the metabolic process of microorganisms by providing electron donors and acceptors. The carbon utilization was up to 97.27% and the concentration of produced VFAs was 33.98 g/L. Metagenomics further illuminated the microbial mechanism and confirmed feasibility of utilizing CO2 to produce VFAs. The integration of hydrogel CO2 capture technique with the biorefinery process improved the utilization of industrial waste gases and efficiency of biomass conversion. This study provides a non-toxic and environmentally friendly process in industrial waste gas separation and high value utilization.