What is the relationship between the alkalinity of water and its hardness?-Yuanlai Water Treatment

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What is the relationship between the alkalinity of water and its hardness?

Released Date: Aug 18,2015 Article Source: Yuanlai Water Treatment

The hardness of water refers to the total concentration of Ca2+ and Mg2+ in water, which includes carbonate hardness (calcium and magnesium ions precipitated in the form of carbonic acid through heating, also known as temporary hardness) and non-carbonate hardness (the part of calcium and magnesium ions that cannot precipitate after heating, also known as hardness). The alkalinity of water refers to the content of substances in water that can accept [H+] ions to undergo neutralization reactions with strong acids. The substances that produce alkalinity in water mainly include carbonate alkalinity produced by carbonates, bicarbonate alkalinity produced by bicarbonates, and hydroxide alkalinity produced by the presence of hydroxides. Therefore, alkalinity represents the total amount of carbonate ions, bicarbonate ions, hydroxide ions and some other weak acid salts in water. The aqueous solutions of these salts are all alkaline, but

The hardness of water refers to the hardness of waterCa2+,Mg2+The total concentration, which includes carbonate hardness (calcium and magnesium ions precipitated in the form of carbonic acid through heating, also known as temporary hardness) and non-carbonate hardnessThe part of calcium and magnesium ions that cannot precipitate after heating is also known as hardness"

The alkalinity of water isIt refers to something acceptable in water[H+]The content of substances in which ions undergo neutralization reactions with strong acids. The substances that produce alkalinity in water mainly include carbonate alkalinity produced by carbonates, bicarbonate alkalinity produced by bicarbonates, and alkalinity caused by the presence of hydroxides"ProducedThe hydroxide alkalinity. So, alkalinity represents waterCarbonate ion,Bicarbonate ion,Hydroxide ionAnd the total of some other weak acid salts. The aqueous solutions of these salts are all alkaline and can be neutralized by acid. However, in natural water, alkalinity is mainly determined byBicarbonate ionIt is composed of salts.

Starting from the concepts of the two, hardness is directly related to cations, while alkalinity is related to anions. Although there seems to be no direct relationship on the surface, hardness can temporarily link the two.

①Hardness＜Alkalinity

All the hardness ions in waterCa2+,Mg2+"Both"HCO3－Combine to becomeCa(HCO3)2andMg(HCO3)2So the hardness is equal to the temporary hardness, while the alkalinity is greater than the temporary hardness.

②Hardness=Alkalinity

The hardness ions and alkalinity ions in water are the sameCa(HCO3)2andMg(HCO3)2In the form of existence, there is neither excess hardness nor hardness, so hardness, alkalinity and temporary hardness are equal.

③Hardness＞Alkalinity

The hardness in water, apart from combining with alkalinity ions, isCa(HCO3)2andMg(HCO3)2Beyond, superfluousCa2+,Mg2+It combines with the strong acidic anions chloride ions and sulfate ions in water respectively to formCaCl2,CaSO4,MgCl2,MgSO4. At this point, the alkalinity is equal to the temporary hardness, and the hardness is greater than the temporary hardness.

According to the relationship between alkalinity and temporary hardness, water can also be classified into negative hardness and permanent hardness.

Negative hardness refers to water with an alkalinity greater than its hardness, where there is an excess of hardness in the water, that is, an excessHCO3-With waterNa+,K+Combine to form bicarbonate.

Permanent hardness refers to water with an alkalinity lower than its hardness, which is why hardness exists in the book.

Keywords: Water Softening Equipment Automatic Water Softener Reverse Osmosis Equipment Manufacturer of Water Treatment Equipment

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