Investigation of, Calcium (Ca2+) and Magnesium (Mg2+) effects on water hardness and taste by using EDTA (Ethylenediaminetetraacetic Acid) Method and clarification between pH and total hardness.

摘要

A question ''what causes the taste difference between the water I drink?'' came to my mind during the planning stage of this test? I had four different water to figure out this. I thought about reasons for the difference between this water, what kind of metal-based softening was made when softening water hardness, factors they were dependent on and how they changed or did not change. I wanted to investigate what was the water hardness of the samples used and to which hardness standard these samples conform by using the EDTA (Ethylene Diamine Tetra Acetic Acid) method and by determining the calcium and magnesium amounts and total hardness ratios. In addition, I decided to investigate reflection of these metal ions on pH. udWater is the most important compound which is necessary for the existence and survival of mankind. About 4/3, in other words, 80%, of our world consists of water and only 1% of this water is drinkable. Water is the most abundant compound in living being. 80% of children's weight and up to 55-60% of adults' weight consists of water.1 However, the ratio of potable water is becoming increasingly inadequate depending on the increasing rate of population growth and seasonal changes. Therefore, it is necessary that water should become potable. This condition of becoming potable is generally achieved by dilution or softening using various methods and by reducing and even eliminating of various elements (calcium, magnesium, iron) in water. Thus, water becomes potable both in terms of taste and appearance. Recycling of water, our most basic need, is achieved in this way.udWater hardness is defined as the feature of water to consume soap (without foaming). Water from natural resources absorbs CO2 from the air and thus, becomes acidic. Such water releases salt inside of rocks consisting of Mg+2 and Ca+2 when it comes into contact with them. Water containing such Mg+2 and Ca+2 salts at certain rates is referred to as hard water. If soaps with sodium and potassium content are added into such water, Na+ and K+1 ions are replaced by Mg2+ and Ca2+ ions and cause the formation of precipitates. This situation continues until precipitation of all the ions causing hardness. Soap will begin foaming after all of Mg2+ and Ca2+ ions in the setting precipitated. 2udThe process of transforming and precipitating Ca2+ and Mg2+ metals into water soluble and non-water soluble compounds when performing processes for water hardness or the process of replacement of Ca2+ and Mg2+ elements with sodium element as with zeolite is referred to as softening of hard water. udThus, the efforts performed have revealed whether the differences between the two water are caused by Mg2+ or Ca+2 and it has been endeavoured to facilitate understanding of the process with the methods applied.