Does Copper reacts with Sodium Sulfate solution?
If you're trying to make an electrolytic capacitor, you've picked inappropriate materials.

An electrolytic capacitor works because a material such as aluminum or tantalum develops a tightly-adherent insulating oxide layer when immersed in certain solutions and "formed". Copper does not have an adherent insulating oxide; instead, cuprous oxide is a semiconductor and $\ce{Cu2O}$ can be used to make a rectifier.

You can make your own aluminum electrolytic capacitor with common household chemicals.