Fabrication of polypyrrole-graphitic carbon nitride nanocomposite containing hyper-cross-linked polyamide photoresponsive membrane with self-cleaning properties for water decontamination and desalination applications

Abstract

A new photoresponsive hyper-cross-linked polyamide thin film nanocomposite nanofiltration membrane was fabricated by incorporating polypyrrole-graphitic carbon nitride (PPy@G-CN) nanocomposite photo-catalyst through interfacial polymerization for water decontamination and desalination applications. An ultrafiltration polysulfone/polyethylene terephthalate (PSf/PET) membrane support was prepared through phase inversion and a hyper-cross-linked PPy@G-CN/polyamide active layer was fabricated on the PSf/PET by using N,N-bis(2-aminoethyl)-1,3-propanediamine (as an aqueous amine) and terephthaloyl chloride (TPC as a non-aqueous solution) while different amounts of PPy@G-CN nanocomposite photo-catalyst were homogeneously dispersed in aqueous amine solution before interfacial polymerization reaction and three fabricated membranes were named as x%-PPy@G-CN/HCPAMs. Out of the three fabricated membranes, 0.10%-PPy@G-CN/HCPAM was found to be the best performing membrane in terms of flux and % rejection. The maximum water flux of the membrane was found to be 78.57 L m−2 h−1 at 25 bars with rejection of Eriochrom Black T (EBT) approaching 99.90% at 20 bar. Moreover, the 0.10%-PPy@G-CN/HCPAM also showed a remarkable rejection of 79.58% and 72.88% for MgSO4 and NaCl, respectively. The 0.10%-PPy@G-CN/HCPAM showed exceptionally high photocatalytic self-cleaning as all of the organic fouling (coloration) due to EBT was removed under simulated solar light irradiation for 1 h leading to photocatalytic degradation of EBT. The 0.10%-PPy@G-CN/HCPAM membrane remained physically intact even after elongated exposure to light source.