The calcium and magnesium levels in the saltwater are above the standard
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This post was last edited by sunjl1981 on 2013-1-6 23:32. Excessive levels of calcium and magnesium in saltwater – how can this lead to a decrease in chlorine purity? # ， ， &
Excessive levels of calcium and magnesium in the saline solution deposit on the membrane, blocking the ion channels; this increases the amount of OH- that migrates back toward the anode. Oxygen is generated during discharge at the anode, resulting in a decrease in chlorine purity.
Haha, I learned this from them as well; if the sulfate level is too high, the same phenomenon occurs. This post was last edited by dqlhb on 2008-2-21 13:15]
How does the back-migration amount of hydroxide increase? Does channel obstruction cause this increase? Adding hydrochloric acid simply won’t solve the problem.
During the electrolysis of brine in the cell, hydroxide ions in the anode chamber pass through the membrane to the cathode chamber. An extreme scenario can be assumed: First, assume that there is no diaphragm, and that the saltwater does not stay in the anode chamber at all, but goes directly into the cathode chamber. In this case, the current efficiency is highest, as the concentration of sodium chloride in the anode chamber is greatest, meaning that sodium chloride is more likely to be ionized. All hydroxide ions end up in the cathode chamber, without participating in any side reactions; as a result, the purity of chlorine gas is at its highest. II. Assuming the diaphragm has no pores, saltwater cannot reach the cathode chamber; electrolysis can only take place in the anode chamber. Over time, the concentration of sodium chloride in the anode chamber decreases, while the concentration of hydroxide ions increases. As a result, the probability of hydroxide ions being discharged at the anode also increases gradually. Finally, all the chloride ions are converted into chlorine gas, after which water is electrolyzed directly; a large amount of oxygen is released in the anode chamber, and oxygen gradually replaces chlorine in the chlorine system. The increase in calcium and magnesium ions in the saline solution continuously reduces the porosity of the membrane; in other words, the operation of the electrolyzer is a process that gradually transforms from one state to another. The above are merely personal opinions.