Breaking the mass transfer barrier of CO2 hydrate films under static conditions via sodium lignosulfonate-amino acid synergy and temperature perturbation

CO 2 hydrate-based sequestration offers a potential route for long-term atmospheric CO 2 storage, but its application under static conditions is limited by slow hydrate formation kinetics with long induction times and by hydrate films that form at the gas–liquid interface, blocking CO 2 dissolution and diffusion and causing premature reaction termination. This study first examined the environmentally friendly promoter sodium lignosulfonate (SL) at 0.1–5 wt.% under static conditions. Although SL achieved gas consumption comparable to SDS, it still showed long induction times, low reaction rates, and a crystal morphology transition from mycelium-like to coral-like structures. To overcome these kinetic deficiencies, two strategies were adopted. First, SL was compounded with amino acids to shorten induction and accelerate hydrate growth through synergistic effects. Second, a dynamic temperature perturbation strategy was introduced to periodically vary subcooling, disrupt the hydrate film barrier, and restore gas–liquid contact. The results showed that compounding with L-leucine reduced the induction time by 23 %–42 % and shortened T 90 by approximately 58.1 %. Temperature perturbation reactivated the mass-transfer-limited reaction, converting passive waiting time into effective reaction time and increasing the reaction rate by nearly an order of magnitude. These two strategies address the kinetic bottlenecks of the SL system through chemical promotion and physical intervention, respectively. Their synergistic application provides a feasible operational framework for advancing hydrate-based CO 2 sequestration from laboratory research toward engineering scale-up.