Distilled Water vs. Deionized Water
Purified water is an important solution, which plays a role in a variety of applications. However, not all purified water is the same. Though purification processes result in similar products, they do so through incredibly different methodologies. These variations in method impart different properties to the resulting water. Distillation and deionization are two of the most wide-spread purification procedures. A close examination of these processes can best reveal the differences between the results.
Distillation is a physical process, which relies upon boiling point differences to separate mixtures. In essence, this can be envisioned as a pot of water boiled on a stovetop. By capturing the water vapor and then condensing it in a separate pan, the water can be separated from any impurities that may have been floating within it. These impurities will remain in the original dish, and may include mineral salts, bacterial or biological impurities, as well as other solutions, which may have been mixed into the water itself.
Although distillation is a reliable purification method, it sometimes requires multiple iterations to deliver the best possible product. Double distillation is the method most often used in scientific laboratories; as the name suggests, this reintroduces a distilled solution back through the distillation process a second time. Although one hundred percent purity is an impossible standard to achieve, a double distilled solution yields some of the purest waters possible.
Of course, the distillation process does have its drawbacks. The method can be a slow one. It is also a costly one. Although the product is reliable, its drawbacks must be weighed with its benefits.
Deionization is a chemical process, which utilizes the natural electrical charges found in mineral ion impurities to remove those ions from a solution. Water is an excellent solvent. When allowed to stand for long periods of time, it can dissolve elements or ionize minerals that are found in its proximity. This can lead to impurities such as calcium, copper, and sulfates floating freely around in the water. Even if these mineral salts are not visible to the naked eye, they may still be present. A salt’s nuclear composition includes both protons and electrons, and the ratios between these particles give many mineral salts a small positive or negative electrical charge.
Scientists take advantage of these charges by passing water through filters that contain large amounts of anions and cations. By using the basic electrochemical property that opposite electrical charges attract, this purification method can then remove the salts by encouraging bond developments. Bonded molecules are far easier to filter from solution because they have a much larger size than a single charged ion alone. This results in water that has been stripped of charged ions.
Deionization is a relatively inexpensive one when compared to the distillation process; however, the method has a different set of drawbacks. For example, the process does little or nothing about any non-polar salts that may be in the solution. Polarity is another term for the electrical charge. Some salts do not carry a charge at all. Furthermore, the deionization process will not resolve any biological agents, so bacterial impurities may still be present.