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Reverse Osmosis Removal & Rejection Rate Information

Question Shortcuts:
Will RO Remove:

…Lead?

…Arsenic?

...Volatile Chemicals?

Will Manganese -Greensand Remove Zinc or Aluminum?

... hydrochloric and phosphoric acids?

... Hydrocarbons?

...hydrogen sulfite or manganese?

NF has negative rejection of Nitrates & Low Rejection of Chlorides.

...Formaldehyde?

...Trichloroethylene?

...Fluoride?

...antimony, arsenic, lead, and thallium?

Note:  Also see our Nominal Rejection Characteristics for membrane rejections of common contaminants.

Are Lead and Arsenic Removed by Thin Film Reverse Osmosis Membranes?  What are the rejection rates?


There is not a list of rejection rates for these heavy metals, but we can give you some general guidelines. However, we recommend that you run the experiments under your unique set of conditions and ions/counterions.

Rejection of lead by thin film RO membranes has been reported to be quite high, >99%.

The rejection of arsenic depends on its oxidation state. The +3 acid, arsenious, is not rejected particularly well in neutral solutions, 70 to 90%, but is well rejected as the pH approaches or exceeds the pKa of 9.2. The +5 arsenic acid is well rejected in neutral solution.


How efficient is reverse osmosis system in screening out volatile chemical? such as MTBE, MTM, etc?


Reverse Osmosis does not effectively remove these chemicals.  In fact, such chemicals can damage membrane elements.


In water showing 5400 ppb iron, 440 ppb zinc, and 270 ppb aluminum, would a manganese-greensand filter have any effect on the zinc and aluminum levels?


No. The levels of zinc and aluminum will be unaffected by the manganese greensand filter. Reverse osmosis will remove these metals, but a 2-pass RO system  is recommended . 


Can I remove hydrochloric and phosphoric acid from water using RO?


No. This is not a good application for RO.


Can Water containing Hydrocarbons in ppb levels (like benzene and other aromatic , aliphatic hydrocarbons) be treated by Membrane Technology?


No. Hydrocarbons are not removed by membranes.


What effect does hydrogen sulfite and/or manganese have on RO membranes?  If any, what levels would the membranes tolerate?


Hydrogen Sulfide would have no effect on the membranes, and is not removed by the membranes.

Manganese will foul the membranes and can cause fouling at levels in excess of 0.2 ppm in water.


Nano-filtration shows negative rejection of Nitrates and very low rejection of Chlorides.  Is this correct?


Yes, This is typical of nanofiltration membrane performance.


Is it possible to remove formaldehyde from water by using RO?  If so, which membrane would you recommend?


Membranes cannot be used to remove formaldehyde from water.


Can I remove TCE (trichloroethylene) from water using RO Membranes?
 


No.  You will need a specially designed carbon system for this application.


Will Microfiltration remove Fluoride?
 


No, Micro filtration will NOT remove Fluoride.  However, reverse osmosis has been used to reduce Fluoride content by 90-98%.


Can I remove nitrates from our well water when using an RO unit?
 


Nitrate removal when using reverse osmosis membranes is about 80%. So if you currently have 40 ppm of nitrate, then your levels after treatment should be around 8 ppm.


Can I remove Boron with your R.O.?
 


Boron is removed at an average of 50-70% using a thin film reverse osmosis membrane. Please refer to the attached chart for additional information on membrane rejection.


We are facing a problem with scaling due to hard water, what would you suggest to solve the problem?
 


You may consider using a water softener.


 


Do RO membranes reject antimony, arsenic, lead, and thallium?

Some general guidelines are given below, but need to be verified by pilot testing for each situation.
Rejection of lead by thin film RO membranes has been reported to be quite high, >99%.

The rejection of arsenic depends on its oxidation state. The +3 acid, arsenious, is not rejected particularly well in neutral solutions, 70 to 90%, but is well rejected as the pH approaches or exceeds 9.2. The +5 arsenic acid is well rejected in neutral solution.


 

 

 

 
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All Content on this site is  intended for informational purposes for experienced water treatment professionals only.  Applied Membranes, Inc. does not assume any liability for any damages caused by the misapplication or misinterpretation of any of the information contained on this website.
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