How to remove the chlorine ions on stainless steels surface

A. Hi S.M. I think the question you are asking is not quite the best one. Rather than talking yourself into working around the specification, the better question might be something like "how can I economically provide the required water of 2 ppm chlorine?" :-)

I don't know whether the chlorine exposure can cause permanent damage to the stainless steel or not, but I don't think we can just arbitrarily rule out that possibility, and assume that it's okay to use chlorine contaminated water for the test as long as we later rinse it off.

First of two simultaneous responses --

A. I would look into getting a reasonable sized reverse osmosis unit. A good pre filter, then a granulated carbon filter followed by a lower micron filter than your first filter will remove a large amount of chlorine, but NOT chloride. Recycle your water thru the RO unit into a storage tank that is plastic.

Second of two simultaneous responses --

A. Usually 2 ppm of chlorine does not cause enough of a problem to worry about. If it is chlorIDE, it is more of a problem.

Ted is correct, in that it is not too hard to make water that is less than 2 ppm of chlorine. What quantity are you talking about? There are not too many chlorides that are insoluble in that low a concentration, so you probably need to go to a RO or DI process. You could rent a DI system probably.

A. Please clarify if your problem is chlorine or chlorides. Removal of chlorine is usually accomplished with activated carbon or then addition of sulfites. Chloride removal is usually by ion exchange or reverse osmosis.

For nearly complete chlorine removal, up to 10 minutes of contact time with activated carbon is needed. If chloramines are present, even longer contact time may be needed. Sulfite addition can be controlled by an ORP controller, or if the chlorine concentration is relatively constant, by a simple, flow proportional dosing rate and a test kit to monitor it.

A. If this is just a stainless steel outer casing that has rusted due to proximity to chloride-heavy vapors or fluids, it should be cleaned and repassivated. This kind of chloride exposure can be mitigated with regular rinses of fresh water and frequent passivation treatments.