Affinity adsorption. Removal of pharmaceuticals at the source
Many pharmaceuticals are present in urine and feces and end up in wastewater via the toilet. Sewage treatment plants (WWTPs) in general have not been designed to remove pharmaceuticals, and appear to remove only about 70 % of the total amount of pharmaceuticals. The remaining pharmaceuticals are discharged into surface water. This may negatively affect the aquatic environment and the production of drinking water.
Adsorbents like activated carbon may be used to remove organic micropollutants like pharmaceuticals from water, but their efficiency is decreased by the presence of natural or effluent organic matter. These OM compounds, which are present in concentrations in the order of magnitude of mg/L (whereas micropollutants are only present in μg/L) compete with the micropollutants for adsorption sites, thus reducing the adsorption capacity of the adsorbent for micropollutants. Pharmaceuticals always contain functional groups in their molecular structure. These can be used for specific interactions with compounds present at the adsorbent surface. In a previous project (Hofman-Caris et al., 2015) it was shown that when adsorbents, which can show such interactions are applied, competition with other organic compounds is prevented. However, the adsorbents used in that project were too expensive for large scale applications. Therefore, in the present project we tried to find a more cost effective carrier material and surface modification.