Tailoring thin film composite membranes for enhanced removal of heavy metals from water

In response to the pressing need for effective removal of heavy metals from water sources, this study focuses on the optimization of Thin Film Composite nanofiltration membranes, known for their porous polymer support and selective ultrathin layers. The objective was to enhance the rejection of heavy metal ions, a critical issue in water treatment. The parameters of the interfacial polymerization (IP) process, including monomer concentration, reaction time, curing temperature, and curing duration, were tailored to determine the most effective membrane configuration. Polyimide (P84) was employed as the support material, with the IP involving trimesoyl chloride (TMC) and piperazine (PIP). Comprehensive characterization through Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and water contact angle measurements provided information on the functional groups, surface and cross-sectional morphologies, and hydrophilic properties of the membranes. The optimized fabrication conditions, involving 0.2 w/v% TMC and 2.0 w/v% PIP monomer concentrations, a 2-minute IP reaction time, and a 40°C curing temperature for 10 minutes, led to the membranes achieving arsenic and chromium rejections of 89.7% and 99%, respectively. This was accomplished while maintaining a high pure water permeability of approximately 16.9 Lm⁻²h⁻¹bar⁻¹. These promising results highlight the potential of these optimized nanofiltration membranes for industrial applications, addressing a critical environmental challenge.