Sciencemadness Discussion Board

Compact Flow-Through Electrochemical Cell for Perchlorates

jpsmith123 - 1-10-2020 at 19:21

Here's a paper I recently found that may be of interest.

Attachment: TOCENGJ-13-23.pdf (1.6MB)
This file has been downloaded 371 times

mysteriusbhoice - 1-10-2020 at 21:36

ive heard of this type of cell before and never really tested it but a bed of powder PbO2 made from anodizing lead in sulfuric acid solution might work for this and all you need is a graphite rod inserted in that bed in a dry area of it.
Doing so might allow the amateur to make a batch mode process out of this setup.

According to that paper he used an MMO ribbon or tube for corrosion control as the anodic current feed.

MMO will survive a perchlorate cell in its early stages but it makes sense that the bed is at continuous flow which prevents the buildup of perchlorate which can damage some types of MMO.

recommended to use magnetite made by a furnace at 800 Celsius and carbon steel + steam for your current carrier as while that will absolutely be inactive as a material for making perchlorate I heard it can survive perchlorate cell conditions.

You can try MMO as the current collector but I think its a bad idea in an amateur setting.

[Edited on 2-10-2020 by mysteriusbhoice]

yobbo II - 5-10-2020 at 11:29

It reminds me of the Pinkston anode.

A great big bag of lead dioxide pieces with a graphite rod stuck into them for a Perk. anode.

How long will the current feeder last? It's simply an MMO tube (not simple at all). A Ti pipe coated with MMO.
I suppose a mesh will do instead.
Will it not erode in a perchlorate cell.

pbo2_bed.png - 25kB

mysteriusbhoice - 5-10-2020 at 22:35

MMO wont erode in a perchlorate cell if its only used as a carrier and not the main electrode but I have my doubts of making this process work in labscale.

yobbo II - 6-10-2020 at 12:08

It may erode as the current carrier. It will be exposed to the solution and some current will go from the MMO into the solution. ie. it will be working as an anode whether you want it or not.

Fantasma4500 - 30-10-2020 at 06:18

i remember something about fiber cloth wrapped around graphite electrodes to keep them together, it supposedly worked but never got to try it out myself... so methinks- same deal could be done with PbO2 maybe? PbO2 decomposes at 290*C apparently, what if someone pressed PbO2 with an inert material, maybe grinded down the rods well so the surface would be perfectly smooth- i have no idea what materials would work well for pressing, and even less which would be able to resist electrolytic cell

as for the PDF, i dont quite understand- do they say that titanium metal plates wouldnt work out for squashing the lead dioxide in between? if one could make loads of tiny little holes, or maybe somehow produce chips of PbO2 and then sandwich that inbetween some titanium mesh that should work too, yea? it just seems weird to me that the titanium would entirely passivate like that
i really dont fancy the idea of plastic due to its low melting point

maybe if PbO2 was put into a steel pipe and the steel pipe was heated just enough to contract it would give many tonnes of pressure to force the PbO2 into some compacted form