Enhancing the stability of CO 2 foams is critical for improving gas mobility control and storage security in carbon sequestration applications. This study presents a novel investigation of single-step synthesized TiO 2 nanofluids combined with anionic (SDS) and cationic (CTAB) surfactants to quantify nanoparticle partitioning and its impact on foam stability using complementary foam, spectroscopic, and rheological analyses. Synthesized nanofluids exhibited stable dispersion with particle sizes of 51–65 nm and zeta potentials between −33 and −48 mV. Foam stability measurements showed that SDS at its critical micelle concentration (2300 ppm) achieved a foam half-life of approximately 460 s, compared to less than 100 s for CTAB (300 ppm). The addition of TiO 2 nanofluids further enhanced stability, producing finer foam textures with 25–40% reduction in bubble size and significantly delayed coalescence. UV–Vis spectroscopy revealed nanoparticle depletion of approximately 18–35% from the bulk phase after foaming, while rheological analysis showed viscosity reductions of 30–45%, confirming nanoparticle migration and interfacial capture. SDS–TiO 2 systems demonstrated greater nanoparticle utilization and stronger interfacial reinforcement compared to CTAB systems, resulting in superior foam persistence and drainage resistance. The novelty of this work lies in direct correlation of nanoparticle partitioning, rheological behavior, and bubble-scale evolution to explain foam stabilization mechanisms. These findings provide new mechanistic insight into nanoparticle-assisted CO 2 foam stabilization and identify TiO 2 –SDS hybrid nanofluids as promising candidates for improved mobility control and long-term carbon storage in subsurface environments.
Srivastava et al. (Mon,) studied this question.