What do people do when the ion membrane gets contaminated?
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The ion exchange membrane is contaminated by nickel and calcium (the performance of the ion exchange membrane is high according to analysis, but ICP analysis shows normal levels); moreover, the iodine content in the brine remains high, at 3PPm. As a result, the electrical efficiency has decreased while the cell voltage has increased. What measures would you take to prevent this situation from worsening if you encountered it?
The cathode is rinsed with a 2% alkaline solution, while the anode is rinsed with pure water to clean the film. This might improve the performance of the membrane a little bit.
How long should pure water be circulated for the anode? Is the cathode immersed in 2% alkaline solution or is it circulated? Is this your personal advice?
This is the method provided by the manufacturer; we have used it before. Both the anode and cathode need to be cycled; we ran it for over 12 hours at that time.
Which brand of battery do you use?
We used electrolytic cells from Chlorine Engineering at that time. Personally, I feel that this operation is designed for ion exchange membranes, so it is applicable to various models of electrolyzers.
The effect of soaking is definitely not as good as that of circulation. As long as the cathode maintains an alkali concentration of not less than 2%, the anode uses pure water, and the processing time is not too long, the membrane will not bubble. We were in circulation for over 12 hours at that time. If you want to save costs, 2% of the alkaline solution from the cathode can be used in waste gas treatment along with sodium hypochlorite.
The above procedure is what’s known as membrane cleaning, but it is likely to have little effect. To prevent further deterioration, it is necessary to improve the quality of the saline solution; if needed, the membrane should be replaced, otherwise the electrode coating will get corroded
Both the anode and cathode require circulation; are there any requirements regarding the circulation temperature?
Keep the catholyte temperature at around 40 degrees Celsius.
Maintain a weakly alkaline pH at the cathode; use pure water at the anode. Control the temperature properly, soak for 4 hours, then drain the liquid – circulation must be avoided.