“TIO₂-ENABLED NANO BIOREACTORS FOR CARBON CAPTURE, UTILIZATION, AND STORAGE (CCUS)”

Abstract

The rapid increase in atmospheric CO₂ levels caused on by industrialization and the combustion of fossil fuels threatens the stability of the global climate. This paper offers a novel TiO₂-enabled nano bioreactor system that maximizes carbon capture, utilization, and storage (CCUS) by leveraging biological and photocatalytic processes. The sol-gel produced by synthesis TiO₂ nanoparticles have been investigated using XRD, FTIR, SEM, UV-Vis, and BET analyses. These analyses confirmed the formation of highly crystalline, mesoporous anatase TiO₂ with superior photocatalytic and adsorption properties. By enhancing biocompatibility by making, it easier for immobilizing Chlorella vulgaris microalgae, surface functionalization with APTES produced a hybrid nano-bioreactor that can reduce CO₂ in a synergistic manner. When put under visible light illumination, the TiO₂ nano bioreactor displayed a significantly higher CO₂ reduction efficiency of 78% within 24 hours when compared with bare TiO₂ (32%) and free algal systems (45%). Its fundamental product, methanol (0.86 mmol/g TiO₂), followed by formic acid (0.42 mmol/g TiO₂), demonstrated the selective conversion of CO₂ to value-added fuels. The results of mechanistic analysis, photoexcited electrons from TiO₂ assisted with CO₂ photoreduction by converting to intermediates, which were eventually subsequently broken away by algal cells using enzymatic processes. After five consecutive cycles, the system sustained 86% of its initial activity, showing outstanding operational stability and reusability. In addition to these research results, TiO₂-enabled nano bioreactors offer an affordable, safe, and versatile way to decrease carbon emissions and generate renewable energy.