Membrane Separation & Desalinization

Membrane Separation, commonly referred to as Reverse Osmosis, is a process which is used to remove dissolved contaminants from water. It is used in the generation of potable water from salt, brackish, well or surface water, the manufacture of process water (eg ultrapure water for the power and electronic industries) and for re-use of waste water. Reverse osmosis (RO) is an advanced water treatment technique, which produces clean water by applying pressure high enough to overcome the osmotic pressure. Water molecules are transported through the semi-permeable membrane, while the undesired dissolved and suspended solids will remain in the concentrate stream. Very pure water is produced, as even low molecular weight ionic species and many organics do not pass through the membrane. As you might imagine, the concentration of salt builds up on the membrane side where the pressure is applied. This can lead to loss of efficiency of the membrane. Dequest® phosphonates can be used to inhibit scale formation on the high pressure side of the membrane. Italmatch’s Membrane Solutions team offers SPE antiscalant products for different types of scale. Our scale inhibitors can save you money being able to:

  • Extend membrane shelf life through effective scale inhibition,
  • Reduce the downtime caused by frequent membrane cleanings,
  • Improve plant operations via; (stabilizing high recover rates, reducting energy costs, reducing water consumption and concentrate production)
  • Reduce overall chemical treatment costs (pretreatment, acid, antiscalants and cleaners).  

Desalination of water in arid regions, such as the Middle East, has become a common operation. The process can be based on distillation or membrane separation. Dequest® phosphonates and polymers can be used as antiscalants and dispersants to prevent scale build up on heat transfer surfaces and reverse osmosis membranes.

Scaling of heat transfer surfaces in vapour compression systems, MSF's (Multiple Stage Flash Evaporators) or MED's (Multiple Effect Distillation) is a major problem. Scaling reduces heat transfer efficiency and decreases water production. Sulfuric acid fed to the evaporators to reduce carbonate scale formation, comibined with the inherent high temperatures of such systems, often leads to the formation of calcium sulphate scale.

Dequest® polymers and phosphonates, being highly effective threshold scale inhibitors with excellent thermal stability, are a natural choice to control calcium sulphate scale in MSF's, MED's and vapour compression systems. Dequest® phosphonates also bring the added benefit of reducing metal corrosion rates in the units