Comparative behavior of carbon-based materials for the removal of emerging bisphenol A from water: adsorption modelling and mechanism

This research work is focused on the comparative application of activated carbon (AC), carbon nanofiber (CN), and synthesized graphene oxide (GO) in removing the emerging contaminant bisphenol A (BPA) from water. Scanning Electron Microscopy (SEM) analysis confirmed that the CN exhibits a fiber-shaped network, while synthesized GO have a sheet-like structure. The BET specific surface area of AC was found 1112.31 m2/g which is higher than the GO and CN. In BPA adsorption study, the adsorption parameters namely pH, material dose, contact time and temperature, were optimized by various sets of experiments. The maximum removal of BPA at neutral pH (7.0) was 98 %, 97 %, and 75 % for GO, AC and CN, respectively.. The maximum Langmuir adsorption capacity of AC, GO and CN was 158.7 mg/g, 137 mg/g and 63.3 mg/g, respectively for BPA. The kinetic study substantiated BPA adsorption's conformity with the pseudo -second -order model, suggesting chemisorption onto the carbon materials. Thermodynamic analysis revealed the spontaneity of BPA adsorption, with heat absorption as temperature increased. The reuse efficiency was studied up to 5 cycles and the maximum efficiency was 78 % achieved for GO among three carbon materials. The efficiency of all carbon -based materials was also determined in various spiked real water sample.