Seems like you could just dilute it with seawater at like 100:1 ratio and it would be negligible done offshore. We already dump our shit 5 miles out.

100:1 is overkill and energetically very wasteful. It's a fairly straightforward chemical engineering problem.

gasoline

...sea water. You take 10 units of sea water for every unit processed and you'll get a slight increase in salinity.

A phase diagram tells you exactly how far you need to go.

You know this makes more thermodynamic sense than carbon capture, right?