[nosianu]

Unless you do what the earth did for millions of years and bury the carbon deep underground anything you do will merely create a pipeline effect: When it starts there is a small reduction, but overall there is none as soon as the pipeline is full.

What do you mean by "absorb carbon" anyway - plastic is carbon for the most part, the "H(ydrogen)" in the molecules is tiny in terms of weight (H compared to C atom), and any other atoms mixed in for this or that effect are minor components of what is mostly various kinds of carbo-hydrogen molecules.