Organic resin contaminant

XAD resin nonpolar to polar, volatile, nonvolatile convenient, ambient temperature, large volumes contamination, limited recovery of adsorbed organics, resin preparation 24, 27-30... 

Table I shows that most investigators used exhaustive extraction with a series of solvents of decreasing polarity to remove resin contaminants. The procedure of Junk et al. (5) seems to have gained wide acceptance for preparing resins for sampling water for small amounts of organics.

Recommended Solvent Selection Procedure. Resin contaminants have been identified only recently. Until 1977, only the following resin contaminants were identified naphthalene, ethylbenzene, and benzoic acid (36). The resin cleaning procedure of Junk et al. (5), which uses a series of three solvents of decreasing polarity, removes the widest possible variety of organic contaminants from the resins. This method is necessary when many compounds must be removed. 

Table IV shows the calculated solubility parameter (38) of some of the resin contaminants from Table III. The average total solubility parameters for the XAD-2 and XAD-8 organic contaminants (Table IV) are approximately the same. However, there are differences between XAD-2 and XAD-8 for the average hydrogen bonding and average nonpolar components of the solubility parameter.

It is possible to remove both dissolved toxic anions and cations by placing a cation exchange column and an anion exchange column in series. This system has the ability, depending upon the choice of resins, to remove a wide range of inorganic and organic dissolved contaminants. 

Organic peroxides need to be stored separately from the polyester resins and promoters. If a peroxide is contaminated with a promoter, violent decomposition can result. Promoters should always be thoroughly mixed into the resin prior to the addition of the peroxide to prevent violent peroxide decomposition. Peroxides can become unstable if stored for too long or at too high a temperature. Peroxide manufacturers advice for storage and disposal must be stricdy followed. 

A further problem that may cause contamination of the treated MU water is anion leakage as a result of organic fouling. This significantly affects anion resins, preventing ion removal by ion exchange and thus reducing bed capacity. 

Fouling of pores of ion-exchange resins by the presence of organic contaminants in the water being processed. The resin gradually loses its capacity and requires cleaning. 

Jahangir, L. M. and Samuelson, O., Cation-exchange resins and non-ionic cross-linked polymers in analysis of aqueous solutions for organic contaminants, Anal. Chim. Acta, 100, 53, 1978. 

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