Alternative Adsorbents for the Removal of Polar Organic Contaminants

The removal of polar and ionizable organic contaminants is an emerging concern in the production of safe drinking water. Activated carbon adsorption is one treatment strategy to remove such contaminants, but high carbon usage rates may be required to meet treatment goals. Recently published data showing that high-silica zeolites and carbonaceous resins exhibit higher MTBE adsorption capacities than activated carbons served as a motivation for a systematic evaluation of alternative adsorbents in this study. The overall objective of this research was to compare the effectiveness of alternative adsorbents such as high-silica zeolites and carbonaceous resin to that of granular activated carbon (GAC) for the removal of methyl tertiary-butyl ether (MTBE) and emerging organic contaminants such as pharmaceutically active compounds and endocrine disrupting chemicals from drinking water sources. Apart from niche applications, in which the removal of a specific contaminant such as MTBE is targeted, alternative adsorbents such as high-silica zeolites and carbonaceous resin cannot compete with the effectiveness of activated carbon. Activated carbon will continue to be the most effective broad-spectrum adsorbent for the removal of organic contaminants from drinking water. Isotherm results obtained in this study showed that an activated carbon dose that might typically be added for taste and odor control (10 mg/L) is sufficient to achieve a 2-log removal of many emerging organic contaminants.