A study on behaviour, interaction and rejection of Paracetamol, Diclofenac and Ibuprofen (PhACs) from wastewater by nanofiltration membranes

Along with many other Pharmaceutically Active Compounds (PhACs), Diclofenac (DIC), Ibuprofen (IBU) and Paracetamol (PARA) are the most common type of Non-steroidal anti-inflammatory drugs (NSAIDs), which are frequently reported in drinking and treated waters. Membranes can be used to inhibit the passage of micropollutants (Pharmaceuticals) into water that can be further reused. In this study, two types of loose nanofiltration membranes, that usually are applied for large molecular weight organics, were tested for the filtration of selected small molecular weight drugs from synthetic wastewater. Effect of pH on membrane efficiency showed that behavior of drugs altered with changing pH. Results showed impressive treatment of drugs in the order, DIC (99.7%) > IBU (81.2%) > PARA (49%) along with Total Organic Carbon (TOC) (95.3%) and Chemical Oxygen Demand (COD) (84%) removal. Interestingly, nanofiltration of wastewater containing IBU tablet increased to 90.2% as compared to pure drug (80.5%). Mixture of drugs showed decreased removal of DIC (23%) while removal rates for IBU and PARA increased to 17.1 and 67% respectively. Moderate to high rejection percentage was not due to the molecular sizes of the model drugs but hydrophobicity of drugs played role.