Water purifier water purification is true or false?

"After electrolysis of tap water, the water electrolysis of the water purifier filter does not change color; tap water boils sediment, and the water purifier filters water to boil without sediment. These are actually tricks for businesses to deceive." On the 10th, the water quality of Qingdao city water supply The monitoring center uncovered tricks by businesses through field experiments.

In some mall water purifier sales areas, people can often see the sales staff to do experiments on site, that is, an electrolyzer with iron rods and aluminum rods is put into two identical cups of clear water, after tens of seconds of electrolysis. One cup of water clearly shows the color of rust, while the other glass of water is still clear. At this point, the merchants will explain that the former is ordinary tap water, because the water quality is not good so the electrolysis after the discoloration, while the latter is the water filtered through the water purifier, the water quality is fully up to standard, so there is no problem of discoloration.

“The change of water color by electrolysis does not have any relation with water quality. The reason why tap water changes color after electrolysis is mainly because water contains some electrolytes such as sodium, calcium, magnesium and other metal ions, which make water conductive. When the electrolyzer is inserted into the water, the iron rod of the anode will release iron ions due to the current and combine with other ions to form various iron compounds. These iron compounds are insoluble in water and floccular precipitation occurs.” Qingdao Hairun Water Group Propaganda Minister Zhang Rui said that many merchants selling water purifiers on the market are trying to deceive consumers with electrolyzed water tests.

In order to more intuitively prove that the water quality of the mineral water and tap water can also be electrolyzed, flocks of 250 ml of tap water, Evian mineral water, and Wahaha purified water, each of which meets the standard of water quality, are electrolyzed. In seconds, after standing for a short time, yellow water flocs appeared in tap water and Evian mineral water, and the floc of Wahaha pure water was not obvious. "There is no electrolyte originally in purified water, so basically there will be no floc after electrolysis, but if you add a little salt, it will change color after electrolysis," said Wang Xiaofang, director of Qingdao City Water Supply Quality Monitoring Center.

Extended survey

Tap water heat preservation and hardness related to regular drinking pure water is not good for health

"After boiling, my home, there was some white sediment in the bottom of the pot. Is this because the water quality is not up to the standard?" On the 10th, at the Qingdao City Water Quality Monitoring Center, a citizen asked questions.

In this regard, the staff conducted an experiment called “white sediment in water”, which took 1000ml of tap water, Evian mineral water, Laoshan mineral water, and Wahaha purified water, each of which met the standard of water quality, and was placed on an electric furnace to be heated at the same time. Boil for 6 hours. After standing for two hours, pour out the clear water. It was found that tap water, Evian mineral water, and Lushan mineral water all had white precipitates of varying degrees, and the white precipitate was not visible in Wahaha purified water.

“Natural water and tap water both contain temporary hardness, that is, water contains calcium and magnesium ions that are soluble in water. They are invisible to the naked eye. When heated and boiled, these ions decompose into water-insoluble calcium carbonate and are insoluble in water. Magnesium hydroxide precipitates in water, which is commonly understood as scale, which is a normal phenomenon and has nothing to do with water quality.” Wang Xiaofang said that mineral water contained in tap water is necessary for human body, if there is no drinking for a long time The pure water of minerals is also not conducive to good health.