The understanding of Reverse Osmosis
Reverse Osmosis, commonly referred to as RO, is a process where you demineralize or deionize water by pushing it under pressure through a semi-permeable Reverse Osmosis Membrane.
How Does Reverse Osmosis Remove Impurities?
Reverse Osmosis water purification process is a simple and straightforward water filtration process. It is accomplished by water pressure pushing tap water through a semipermeable membrane to remove impurities from water. This is a process in which dissolved inorganic solids (such as salts) are removed from a solution (such as water). RO works by reversing the principle of osmosis, the natural tendency of water with dissolved salts to flow through a membrane from lower to higher salt concentration. This process is found throughout nature. Plants use it to absorb water and nutrients from the soil. In humans and other animals, kidneys use osmosis to absorb water from blood.In an RO system, pressure (usually from a pump) is used to overcome natural osmotic pressure, forcing feedwater with its load of dissolved salts and other impurities through a highly sophisticated semipermeable membrane that removes a high percentage of the impurities. The product of this process is highly purified water.
What contaminants will Reverse Osmosis remove from water?
Reverse Osmosis is capable of removing up to 99%+ of the dissolved salts (ions), particles, colloids, organics, bacteria and pyrogens from the feed water (although an RO system should not be relied upon to remove 100% of bacteria and viruses). An RO membrane rejects contaminants based on their size and charge. Any contaminant that has a molecular weight greater than 200 is likely rejected by a properly running RO system (for comparison a water molecule has a MW of 18). Likewise, the greater the ionic charge of the contaminant, the more likely it will be unable to pass through the RO membrane. For example, a sodium ion has only one charge (monovalent) and is not rejected by the RO membrane as well as calcium for example, which has two charges. Likewise, this is why an RO system does not remove gases such as CO2 very well because they are not highly ionized (charged) while in solution and have a very low molecular weight.