Demand High-Purity Water

IX can be an efficient solution for a variety of applications, including water softening, purification, separation and pretreatment to protect downstream equipment and improve operational performance.

Ion exchange (IX) systems are utilized for water softening, filtration and separation in a range of industries. While the chemistry of individual ion exchange reactions varies from one application to the next, IX is a treatment process in which dissolved ions are replaced by other, more desirable ions of a similar electrical charge.

Ionic pollutants are removed from solutions using IX systems, which use a physical-chemical process to exchange undesirable ions with ions that have the same electrical charge. When a process or waste stream passes through a resin that allows for ion exchange in an IX column or tank, this reaction happens. A water softening IX system, for example, is intended to remove scale-forming calcium or magnesium ions from the solution. The calcium and magnesium ions are efficiently collected and kept by an IX resin made up of concentrated sodium ions, while the sodium ions are released into the effluent stream.

In terms of both physical design criteria and the IX resin material employed, a well-designed IX system conforms to the demands of a certain application. IX resin, input distribution system, regenerant distribution system, retention elements and PLC, control valves and pipes are all included in a standard IX vessel. The resins are the most important component of an IX system. The geometric shape, size and material employed in the IX resin will be influenced by the components in the feed stream, as well as other process variables.

Ions are charged atoms or molecules. When an ionic material dissolves in water, its molecules split into cations (positively charged particles) and anions (negatively charged particles). This capability is used by IX to replace ionic molecules selectively based on their electrical charges. The ion exchange reaction is mediated by passing an ionic solution through an IX resin, which acts as a matrix.

IX resins can be available as small, porous microbeads or as a sheet-like membrane. IX resins are constructed up of a network of hydrocarbons that bind a large number of ionizable groups electrostatically. They are made from organic polymers like polystyrene. The loosely held ions on the resin’s surface are replaced by ions with a stronger affinity for the resin component as the process or waste stream passes through the IX resin.

The resin becomes saturated with contaminating ions after a period of time and must be recharged or regenerated. The resin is flushed with a regenerant solution to do this. The regenerant, which is commonly a strong salt, acid or caustic solution, reverses the IX reaction by substituting cations or anions on the resin surface and releasing polluting ions into the wastewater.

Sodium zeolite softening is the most prevalent application of IX, although other important applications include high-purity water generation, dealkalization and metals removal. Despite the fact that IX resins must be carefully chosen according on the chemicals present in the feed stream, it can be a very effective approach for removing dissolved pollutants.

Cationic Resins

Strong acid cation (SAC) resins and weak acid cation (WAC) resins are two types of cation exchangers that are widely employed for demineralization. SAC resins are frequently used for softening, while WAC resins are commonly used for dekalification. Cation resins often remove the following contaminants:

  • Calcium (Ca2+)
  • Chromium (Cr3+ and Cr6+)
  • Iron (Fe3+)
  • Magnesium (Mg2+)
  • Manganese (Mn2+)
  • Radium (Ra2+)
  • Sodium (Na+)
  • Strontium (Sr2+)

Anionic Resins

Strong base anion (SBA) resins and weak base anion (WBA) resins are two types of anion exchangers. WBA resins are commonly used for acid absorption, while SBA resins are commonly utilized for demineralization. Anion resins often remove the following contaminants:

  • Arsenic
  • Carbonates (CO3)
  • Chlorides (Cl–)
  • Cyanide (CN–)
  • Fluoride
  • Nitrates (NO3)
  • Perchlorate (ClO4-)
  • Perfluorooctane sulfonate anion (PFOS)
  • Perfluorooctanoic acid (PFOA)
  • Silica (SiO2)
  • Sulfates (SO4)
  • Uranium

Specialty Resins

While speciality IX resins are very successful for specific industrial applications, their greater specificity usually comes at a higher cost and with a narrower application than standard IX resins. Chelating resins, for example, are widely used to concentrate and remove metals such as cobalt (Co2+) and mercury (Hg and Hg2+) from dilute solutions. Magnetic ion exchange (MIEX) resins, meanwhile, are frequently used to remove natural organic materials from feed water.