Principle of alum water purification

Introduction: alum water purification, this is what we learned in primary school So what about the principle of alum water purification? Let the small editor of Baibai safety net lead you to learn more about it! Alum is a common material in our life, but it is also used in most rural areas, especially in families with well water Alum is a good water purification agent, and the price is very cheap, so it can be used for water purification How about the principle of alum water purification? Baibai safety net and you to understand it! The chemical name of alum is aluminum potassium sulfate dodecahydrate, and the chemical formula is Kal (SO4) 2.12h2o After alum dissolves in water, it will decompose into potassium ion, aluminum ion and sulfate ion: Kal (SO4) 2 = K + + Al3 + + 2so42 Aluminum ions can easily form aluminum hydroxide in water: Al3 + + 3H2O = Al (OH) 3 (colloid) + 3H + (reversible) We found that the main role of alum water purification is aluminum sulfate, which chemically changes with water to form a white flocculent precipitate - aluminum hydroxide Aluminum hydroxide is a kind of colloid with strong adsorption capacity, which can absorb insoluble impurities in water and achieve the purpose of water purification Next, we understand why the water is turbid The water is turbid because there are many sediment and other pollutants in the water Larger sediment particles, which stay in the water for a short time, will soon settle down But those small ones, which are small enough to become colloidal particles, will not settle down in a few days Colloidal particles often absorb some ions from water, or ionize some ions by themselves, so that they become a charged particle Scientists have found that sediment colloidal particles are negatively charged When two colloidal particles are close to each other, electrostatic repulsion always separates them, and they have no chance to form larger particles to precipitate Aluminum hydroxide particles are positively charged When they meet with negatively charged silt particles, they neutralize each other The limb particles without electric charge will gather together soon The larger the particles are, the larger they will sink to the bottom of the water, and the water purification work will be completed The above is the answer about the principle of alum water purification provided by Baibai safety net I hope my article will let you have a clearer understanding of this problem! To learn more about food safety, please pay more attention to Baibai safety Internet bar! Editor in charge: Wang Xiujuan