There are people trying that. Whether it's economically any more viable or not is to be seen. Sea water is a soup of microorganisms and minerals that accrete and grow on anything that they can, making longer term use of it challenging.

Stuffing the genie of CO2 back in the bottle after we've released it is much less efficient and effective than not letting it out in the first place. Enhancing nature-based drawdown is the primary real process being delivered and worked on.