Graphene oxide-iron oxide based thin film nanocomposite membrane for congo red dye removal and simultaneous salt recovery from aqueous stream

Abstract

Current work focusses on the synthesis of iron oxide impregnated-graphene oxide incorporated polyvinylidene fluoride based thin-film nanocomposite (TFN) membrane and its application in Congo Red dye removal. Interfacial polymerization with 0.02 wt% graphene oxide significantly improved performance of prepared TFN membranes, achieving over 94% rejection of dye with permeability of 3.6 l/m2·h·bar. Testing performance of the membrane was further validated in the presence of real-life feed wastewater, showing 72% dye rejection over 12 h, while an enhanced 94% rejection was achieved with synthetic dye solution. Superior performance was observed in removal of dissolved solids, conductivity, salinity, nitrate, sulfate and dyes compared to commercial nanofiltration membranes. Effect of different operating conditions on membrane performance were examined, confirming its robust nature. Comprehensive characterization of prepared membrane revealed its superiority in texture and chemical nature. Optimized TFN membrane demonstrated recovery efficiency of 70% for sodium chloride and magnesium sulfate solutions, indicating its potential for desalination approach. Thermal regeneration and long-term filtration studies were conducted to evaluate membrane’s lifespan, indicating long-term durability and effectiveness in industrial applications. Studies also indicated weight loss of 62% over two months, which corroborated biodegradable nature of the membrane samples after exhaustion.