Thin-Film Nanofiltration membrane of polyaniline Decorated graphene oxide via In-Situ polymerization for ion separation

Ion separation membranes composed of graphene oxide (GO) and polyaniline (PANI) have been successfully synthesized using the in-situ polymerization method. Various PANI species, including emeraldine base (EB PANI), emeraldine salt (ES PANI), and pernigraniline base (PB PANI), were incorporated into the GO matrix and subsequently evaluated. The integration of PANI species into the GO matrix resulted in an increased interlayer distance, enhanced surface positive charge, and greater membrane hydrophobicity. Additionally, incorporating PANI improved the membrane's mechanical stability and resilience across a range of environmental pH levels. The membrane's ion separation performance was assessed using feed ions such as Na⁺, Li⁺, Mg²⁺, and Al³⁺. The PANI GO-ES membrane exhibited the highest separation efficiency for Na⁺/Al³⁺ ions, achieving an ideal selectivity value of 76.23 ± 1.25. Conversely, ions with similar sizes and charges demonstrated lower selectivity. The GO-ES PANI membrane also showed superior performance stability compared to other membranes, maintaining a consistent ideal selectivity value for up to 20 h. Overall, the results indicate that the GO-ES PANI membrane offers the best ion separation performance and is recommended for practical applications.