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| - | {{:osmosis-diagrams-300.jpg?100 |Diagram of RO (reverse osmosis) water and DI water (deionized water) purification}} | + | {{:osmosis-diagrams-300.jpg?200 |Diagram of RO (reverse osmosis) water and DI water (deionized water) purification}} |
| RO and DI filters use different physical reactions to clean water. Reverse Osmosis (RO) is often used to partially clean-up tap water to make it roughly 90% to 99% pure. Deionization (DI) filters exchange positive hydrogen and negative hydroxyl molecules for positive and negative contaminant molecules in water. DI filtering and other processes are sometimes referred to as "water polishing." | RO and DI filters use different physical reactions to clean water. Reverse Osmosis (RO) is often used to partially clean-up tap water to make it roughly 90% to 99% pure. Deionization (DI) filters exchange positive hydrogen and negative hydroxyl molecules for positive and negative contaminant molecules in water. DI filtering and other processes are sometimes referred to as "water polishing." | ||
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| Quickly using up the purification capacity of deionization filters can be an expensive option for labs that choose to supply tap water to UltraPure (Type I) Polishing Systems. | Quickly using up the purification capacity of deionization filters can be an expensive option for labs that choose to supply tap water to UltraPure (Type I) Polishing Systems. | ||
| - | {{:deionization-km-400.jpg?400 |}}There are several tests for identifying the purity level of water. The simplest test is a direct measurement of electrical conductivity or resistivity. Most inorganic chemicals are either negatively charged (anions) or positively charged (cations), and therefore transmit an electrical current when electrodes are inserted in the water. The more ions present, the greater the conductivity, or the lower the resistivity of the sample water. | + | {{ :deionization-km-400.jpg?400|}}There are several tests for identifying the purity level of water. The simplest test is a direct measurement of electrical conductivity or resistivity. Most inorganic chemicals are either negatively charged (anions) or positively charged (cations), and therefore transmit an electrical current when electrodes are inserted in the water. The more ions present, the greater the conductivity, or the lower the resistivity of the sample water. |
| Conductivity is expressed in µS/cm (microsiemens/cm) and is used to measure water with a large number of ions present. Resistivity is expressed in megohms-cm and is used in the measurement of water with few ions. Conductivity and resistivity are mathematical reciprocals of each other. Therefore, at 25° C, 18.2 megohm water, which is the highest purity water obtainable also, has a conductivity of 0.055 µS/cm. For comparison, the conductivity of distilled water in equilibrium with CO2 in the air is about 20,000 µS/cm. Resistivity-Conductivity Water Purity Chart for reverse osmosis water and deionized water{{:resistivity-conductivity_water_purity_chart.png?800|}} | Conductivity is expressed in µS/cm (microsiemens/cm) and is used to measure water with a large number of ions present. Resistivity is expressed in megohms-cm and is used in the measurement of water with few ions. Conductivity and resistivity are mathematical reciprocals of each other. Therefore, at 25° C, 18.2 megohm water, which is the highest purity water obtainable also, has a conductivity of 0.055 µS/cm. For comparison, the conductivity of distilled water in equilibrium with CO2 in the air is about 20,000 µS/cm. Resistivity-Conductivity Water Purity Chart for reverse osmosis water and deionized water{{:resistivity-conductivity_water_purity_chart.png?800|}} | ||
osmosisandresin.1552915858.txt.gz · Last modified: 2019/03/18 13:30 by thierry
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