MIL-101(Fe)- and MIL-101(Fe)-NH₂-Loaded Thin Film Nanofiltration Membranes for the Removal of Fluoxetine Hydrochloride from Pharmaceutical Wastewater

In the present study, MIL-101(Fe) and MIL-101(Fe)-NH₂ metal-organic frameworks (MOFs) have been loaded into the piperazine aqueous phase (MA_q membranes) and trimesoyl chloride organic phase (MO_r membranes) of the interfacial polymerization (IP) solutions to fabricate thin film nanocomposite (TFN) membranes. The performance of the bare thin film composite (TFC) and TFN nanofiltration membranes was investigated for the removal of the antidepressant fluoxetine hydrochloride (FLX) from aqueous solutions. The performance of the optimized TFN nanofiltration membrane was evaluated for the removal of sertraline hydrochloride, paroxetine hydrochloride, and nortriptyline hydrochloride antidepressants from water. The results showed that the MO_r membrane loaded with 0.005 MIL-101(Fe)-NH₂ MOFs achieved the highest FLX removal percentage of 84.7%, with a permeance of 5.08 L m^-2 h^-1 bar^-1. The water permeance, FLX, chemical oxygen demand (COD), and total organic carbon (TOC) removal efficiencies of the 0.005 wt % MIL-101(Fe)-NH₂ MOF-loaded MAq membrane were 9.16 L m^-2 h^-1 bar^-1, 77.2%, 98.1%, and 99.2%, respectively. The removal efficiency of the other antidepressants using the 0.005 wt % MIL-101(Fe)-NH₂ MOF-loaded MAq membrane was in the following order: sertraline hydrochloride (75.8%) > nortriptyline hydrochloride (73.1%) > paroxetine hydrochloride (71.5%). These results demonstrate that the loading of a low concentration of negatively charged MOFs into the aqueous phase of TFN membranes can significantly improve their membrane performance for the removal of FLX from pharmaceutical wastewater.