So I was thinking about how I could build this filter when I realized I already have something very similar! If you watch my last video about pumping water through my cell you can see a PVC pipe hanging off the side of the cell with tubes hooked up to it. I built this for electron extraction experiments but it is pretty much the same thing as stans filter! in the tube is stainless steel whool. It sort of forms a capacitor because their is a positive and negative side with spacing between that gas or water can flow throught.
