Bioactive nanofluids for enhancing carbon dioxide captureOA

The pressing need to reduce industrial CO₂emissions has spurred the development of efficient and sustainable alternatives to conventional amine-based solvents.In this study,a series of novel nanobiocatalysts were engineered by immobilizing carbonic anhydrase(CA)onto four types of CO₂-affinitive nanoparticles:zeolitic imidazolate framework-8(ZIF-8),Fe₂O₃,graphene,and graphene oxide(GO).The resulting nanobiocatalysts exhibited enhanced CO₂ adsorption capacities,with GO achieving the highest at 22.4 mg/g,followed by ZIF-8 at 8.6 mg/g at 25℃.When used as nanofluids,all systems significantly outperformed pure water in CO₂ absorption,with GO reaching a maximum CO₂flux of 225 mol/m²·min at 1 bar and 25℃.The presence of immobilized CA contributed to substantial flux enhancements:41.6% for GO,36.9% for graphene,32.0% for ZIF-8,and 21.0% for Fe₂O₃,demonstrating a clear synergistic effect between enzymatic catalysis and nanoparticle-assisted absorption.The GO-CA nanobiocatalyst also exhibited excellent operational stability,retaining over 95% of its initial performance after three reuse cycles.Post-reaction analysis revealed a decrease in GO’s surface area from 1562 m²/g to 338 m²/g,confirming stable enzyme immobilization.These results underscore the potential of GO-CA nanobiocatalysts as a high-performance,reusable,and scalable solution for industrial CO₂capture.