Difference Between Temporary and Permanent Hardness of Water

Thekey differencebetween temporary and permanent hardness of water is thattemporary hardness of water can be removed by boiling the water, whereas permanent hardness cannot be removed by boiling.

We can define water hardness as the measurement of the concentration of totaldivalentions present in water. Examples of some divalent ions present in water are钙ion,magnesiumions, and Fe²⁺ion. However, calcium and magnesium are the most common sources of water hardness. The unit for hardness is ppm per CaCO₃equivalents. There are two types of water hardness: temporary and permanent hardness of the water. Temporary hardness occurs due to the presence of calcium hydrogencarbonate and magnesium hydrogencarbonate while permanent hardness occurs due to sulfates and chlorides of magnesium and calcium.

内容

1.Overview and Key Difference
2.临时水的硬度是什么
3.What is Permanent Hardness of Water
4.Side by Side Comparison – Temporary vs Permanent Hardness of Water in Tabular Form
5.概括

什么是水的暂时硬度？

Temporary hardness occurs due to the presence of calcium hydrogencarbonate (Ca (HCO₃)₂) and magnesium hydrogencarbonate (Mg (HCO₃)₂). Both species decompose when heated and CaCO₃or MgCO₃precipitation occurs. Therefore, temporary hardness can be removed by boiling water.

当碳酸氢钙和碳酸氢镁等矿物质溶解在水中时，它会与碳酸盐和碳酸氢盐和碳酸氢盐一起产生钙和镁阳离子（Ca2+和Mg2+）。水样中存在的这些金属离子会导致水的硬度。除开水外，我们可以通过添加石灰去除水的暂时硬度（石灰是氢氧化钙）。这个加法过程称为石灰软化。

What is Permanent Hardness of Water?

Permanent hardness is due to sulfates and chlorides of magnesium and calcium. In other words, permanent water hardness occurs when water contains calcium sulfate or calcium chloride and/or magnesium sulfate or magnesium chloride. Therefore, we can say that the permanent hardness is equal to the sum of the permanent calcium hardness and permanent magnesium hardness.

These minerals do not precipitate when heated. Therefore, permanent hardness cannot be removed simply by boiling. We can remove permanent water hardness either using a water softener or using an ion-exchange column.

What is the Difference Between Temporary and Permanent Hardness of Water?

由于存在钙碳酸钙（CA）（HCO（HCO），暂时硬度发生₃)₂) and magnesium hydrogen-carbonate (Mg (HCO₃)₂). Permanent hardness is due to sulfates and chlorides of magnesium and calcium. The key difference between temporary and permanent hardness of water is that temporary hardness of water can be removed by boiling the water, whereas permanent hardness cannot be removed by boiling. Therefore, we need to use another method to remove permanent hardness from water, such as the addition of using a water softener or using an ion-exchange column.

以下infographic summarizes the differences between temporary and permanent hardness of water in tabular form.

概括– Temporary vs Permanent Hardness of Water

Hard water is water that has a high mineral content. There are two types as temporary and permanent hardness of the water. Hard water cause precipitation of soap from soap water. It forms deposits that clog plumbing. Therefore, it is important to know the removal processes of water hardness. The key difference between temporary and permanent hardness of water is that temporary hardness of water can be removed by boiling the water, whereas permanent hardness cannot be removed by boiling.

Reference:

1. Arthur, Daniel. “Temporary And Permanent Hardness of Water.” Water Treatment Basics, 25 June 2019,Available here.

Image Courtesy:

1. “Hard Water Calcification” By Bbypnda – Own work(CC BY-SA 3.0)viaCommons Wikimedia