Plants do exchange air but in direct relation the amount of light and water available. This post goes into detail about what kind of plants and mentions a ratio of one plant per 100 square feet. To get an effective filter rate you need good light and adequate water.
From a health and safety point of view this article has a long list of things you could be breathing when you solder including ozone, carbon monoxides and various metal ions. You would be safer using a fume hood which exhausts to the outside and buying a plant to deal with the rest.