Explanation of common terms in water treatment
Anion: An ion (charged atom or atomic group) with one or more negative charges (such as Cl-, OH-, SO42-).
Cation: An ion (charged atom or group of atoms) with one or more positive charges (such as Na+, NH4+, and Ca2+).
Conductivity: An electrical measurement parameter of the ability of water to conduct current. Its value changes with the concentration of ions in the water and changes in water temperature. The unit is μS/cm, which generally refers to 25°C.
GPM (gpm): Gallons per minute. A measurement parameter of water flow. 1.0gpm is equivalent to 227 liters/hour, and 4.4gpm is equivalent to 1.0m3/hr.
Ion exchange membrane: a membrane that contains ion exchange groups and has a selective effect on anions or cations, and does not allow water to pass through.
Ion exchange resin: a resin ball containing ion exchange groups that can adsorb anions or cations.
Megaohm: (MΩ.cm) The unit of electrical measurement parameters used to measure the purity of the water coming out of the deionization system. It is a resistance parameter. Ultrapure water without impurities can reach 18.24 megohm·cm (MΩ·cm) at 25ºC.
PH value: a measurement parameter of hydrogen ion (H+) concentration. The PH value is expressed in logarithms from 0 to 14. A PH value of 0 or near 0 is strongly acidic, a PH value of 7 is neutral, and a pH value of 14 or near 14 is strongly alkaline.
ppb: one part per billion, or μg/l. Used to measure the amount of ions in water, such as the silicon content in ultrapure water.
ppm: One part per million, or mg/l. The parameter unit used to identify the number of total dissolved solids (TDS) in water. This parameter unit is generally used to describe the purity of the water flow entering the EDI module. At low conductivity, 1ppm is approximately equal to 2μs/cm.
Resistivity: A measurement parameter that describes the ability of water to block current. As the ion concentration decreases, the resistivity increases; as the ion concentration increases, the resistivity decreases. This parameter is related to the level of deionization achieved with EDI. The ultrapure water without impurities can reach 18.24 MΩ.cm at 25°C.
Salt: A compound formed after the hydrogen ion in the acid is completely or partially replaced by a metal or a positively charged radical group.
TOC: Total Organic Carbon: The number parameter of the content of active organic compounds in the water sample. The total amount of non-organic carbon (CO2) is the remaining part after subtracting organic carbon from the total carbon. Expressed in ppm or mg/liter.
USP ultrapure water: USP quality requirements, the water is purified by distillation, ion exchange, electrodeionization technology, or other appropriate processes, complies with EPA (United States Environmental Protection Agency) drinking water regulations and contains no additional substances.