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Ion Exchange Resins - Industrial Processes

 

Removal of aromatic and phenolic compounds

From waste waters

 

Many of the materials produced by the phenol industry are toxic and cannot be discharged without treatment. Current treatment processes usually involve biological degradation or chemical oxidation of the waste organics. These processes suffer from two major drawbacks: they are sensitive to operation conditions (and thus offer inconsistent performance) and they destroy the product. Since organic concentrations in waste water tend to be high (1-5%), especially for phenol, recovery of the waste organic can result in substantial cost savings.
Polymeric adsorbents are non-functionalized organic polymers which are capable of removing organics from water. The principle is quite simple. Wastewater is passed through a column containing the polymeric adsorbent. The organic materials are retained on the resin while water and some simple salts pass through. When the resin is fully loaded, the organics are stripped from the resin with solvents or caustic. The organic material may be concentrated by orders of magnitude in some cases. The following recommendations are those being used at the present time. The regenerants used are not the only ones possible. The choice of regenerant (solvent) usually depends on the availability at the particular location.

 

Benzene and Cumene.

Both chemicals are very easily removed from waste water using Amberlite™ XAD™4 polymeric adsorbent. In a properly designed system, leakage of benzene is less than 1 ppm. Regeneration of the resin can be accomplished with a solvent such as ethanol or acetone.

 

Phenol.

Amberlite™ XAD™4 polymeric adsorbent is used in several locations around the world to remove phenol from wastewater. Even high concentrations of phenol (20,000 ppm) in wastewater have been effectively treated. The resin's capacity for phenol increases with increasing phenol concentration. Regeneration of the resin is accomplished in several ways: 1% caustic or solvents such as acetone, methanol and formaldehyde. Acetone is frequently used since most phenol plants also have acetone production.

 

Bisphenol A.

Amberlite™ XAD™4 polymeric adsorbent has been used effectively to remove BPA from waste water. Regeneration can be achieved using caustic or a solvent such as acetone or methanol. Acetone is most commonly used since it is readily available and the BPA/acetone washings can be recycled back into the reactor.

 

Alkylphenols.

Alkylphenols can be removed from wastewater with Amberlite™ XAD™4 polymeric adsorbent. However, since these phenols usually contain large organic side chains, an adsorbent such as Amberlite™ XAD™16N polymeric adsorbent which contains larger pores might be effective. Regeneration is usually accomplished with a solvent such as acetone or ethanol.

 

Recommended Products

 

Amberlite™ XAD™4

High surface area and small pores. Ideal for the extraction of smaller molecules such as phenol.

Amberlite™ XAD™16N

High surface area and medium sized pore for the adsorption of large color bodies.

 

For sampling, pricing, availability or more information please contact your Rohm and Haas representative.

 

Further Reading

 

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