To prevent biological fouling in an electrodialysis device, an electrodialysis device including a membrane electrolysis stack are created. Every membrane electrolysis stack comprises membranes stacked on top of each other and respectively dilute and concentrate compartments arranged therebetween, at least one first and at least one second membrane alternating in succession in the membrane electrolysis stack. At least one first membrane is selected from a group comprising an anion exchange membrane and a bipolar membrane, and at least one second membrane is selected from a group comprising a monoselective anion exchange membrane, a monoselective cation exchange membrane and a proton-selective exchange membrane, with the proviso that the second membranes are respectively selected independently of each other and that at least one first membrane in the membrane electrolysis stack is a bipolar membrane.

A roll-to-roll electroless plating system, including a plating tank containing plating solution, and a web advance system for advancing a web of media along a web-transport path that passes through the plating tank. One or more fluid guides are positioned within the plating tank to redirect plating fluid containing gas bubbles introduced by a gas bubble source away from the web of media as it is advanced through the plating solution in the plating tank.

The method of producing stannous oxide includes: a Sn ion-containing acid solution forming step (S01); a first neutralizing step (S02), which is a step of forming Sn precipitates by adding one or more of alkaline solutions of ammonium carbonate, ammonium bicarbonate, and aqueous ammonia to the Sn ion-containing acid solution to retain pH at 3-6 therein; a Sn precipitate separating step (S03); a Sn precipitate dispersing step (S04), which is a step of dispersing the separated Sn precipitates in a solvent liquid to obtain a dispersion liquid; and a second neutralizing step (S06), which is a step of forming SnO by adding an alkaline solution to the dispersion liquid of the Sn precipitates and then by heating, wherein Na, K, Pb, Fe, Ni, Cu, Zn, Al, Mg, Ca, Cr, Mn, Co, In, and Cd reside in the Sn ion-containing acid solution in the first neutralizing step (S02).

An electroless plating system including an electroless plating solution, a recirculation subsystem and a replenishment subsystem, wherein the electroless plating solution is recirculated and replenished.

The life of a plating solution used for forming a metal oxide coating is extended to efficiently use the plating solution. A method for forming a metal oxide coating includes: forming a metal oxide coating on a surface of a plating target with a plating solution containing a metal compound to form a coating and a boron compound as a reducing agent; and regenerating the plating solution with an adsorption filter that adsorbs boric acid.