(677e) Trace Metal Removal By Adsorption for Ultra-High Purity Amines

For many applications such as electronic and pharmaceutical production process, ultra-high purity organic solvents, such as amines, are always desired with single digit ppb level metal ion impurities, and the demands are ever-increasing. However, metal removal by adsorption processes from organic solutions are rarely reported and available literature is normally for removing metal ions from aqueous solution. Recently, we evaluated several chelation ion-exchange resin adsorbents with different functional groups such as Aminomethylphosphonic, Sulfonic acid/phosphonic acid, and Iminodiacetic for purifying N-Methylethanolamine containing a number of metal ions at tens to hundred ppb levels. The evaluation started with adsorbent screening by measuring the adsorption capacities, all conducted in a Clean Laboratory. Twenty-four trace metals were analyzed with ICP-MS. The best adsorbent was identified among those screened according to the major metal impurity removing efficiency, namely for Fe and Zn. The adsorption isotherm and the breakthrough curve were then measured for the identified adsorbent and a preliminary absorber design was conducted.