Ultra-pure water and deionized water are both types of purified water, but they differ in terms of their level of purity.
Deionized water is water that has had most of its ions removed through a process called ion exchange. This process removes minerals and ions that can cause impurities in the water. However, deionized water may still contain trace amounts of impurities, such as bacteria, dissolved gases, and organic compounds.
Ultra-pure water, on the other hand, is water that has been further purified through additional processes, such as reverse osmosis, distillation, or filtration. This water has an even higher level of purity than deionized water, with fewer impurities and contaminants.
Ultra-pure water is often used in scientific research, semiconductor manufacturing, and pharmaceutical production, where the presence of impurities can interfere with experiments or cause damage to sensitive equipment. In these applications, the ultra-pure water is used as a solvent or a cleaning agent, and any impurities could affect the quality or accuracy of the final product.
In summary, ultra-pure water is preferred over deionized water when the level of purity required is higher, and any impurities in the water can affect the quality or accuracy of the final product.