Optimisation of nanofiltration process for pharmaceutically active compounds: Removal of paracetamol, diclofenac and metoprolol

Abstract This study analyses the effects of operating conditions on the removal of three different pharmaceutically active compounds (PhACs: paracetamol [PARA], diclofenac [DIC] and metoprolol [MET]). The results of the experiments employing nanofiltration (NF) membranes were interpreted using response surface methodology (RSM) analysis of variance (ANOVA). In experiments performed with NF270 membrane under optimal operating conditions (15 bar pressure, 4 volume reduction factor [VRF], 5.7 pH), removal efficiencies of PhACs were 11.5%, 73.8% and 46.8%, respectively. The design of NF processes can help substantially in determining the rejection behaviours and mechanisms of micropollutants. Experiments have shown that in drug active substances removal with NF membranes, the physicochemical properties of the NF membranes used and the compound being PARA, DIC or MET affect the removal efficiency and provide an understanding of the rejection performance. These factors may also provide a guide for the applicability of the NF technology in advanced treatment processes in the future.