Nitrogen rich g-C ₃ N ₄ @GO nanocomposite for micro-solid phase extraction of trace Pb(II) and Cd(II) in environmental water samples

The nitrogen rich g-C3N4@GO nanocomposite was synthesised to developed a method for environmental monitoring and assessment of trace Pb(II) and Cd(II) in real water samples. In the composite sorbent, graphitic carbon nitride (g-C3N4) plays a crucial role and eliminate the stacking of graphene oxide (GO) sheets, thereby, enhances the inter-sheet spacing, which significantly increases the sorption of Pb(II) and Cd(II) ions. Comprehensive characterisation was conducted through FTIR, FESEM, zeta potential, water contact angle and BET analyses. The high hydrophilicity of GO and negative surface potential of g-C3N4@GO composite significantly enhance the adsorption capacity of Pb(II) and Cd(II). At optimum conditions, the method shows a low detection limit of 0.02 μg/L, a quantification limit of 0.07 μg/L and a preconcentration factor of 30. The methods accuracy was confirmed by analysing Standard Reference Materials SRM 1572 and NIES 10c with RSD < 5% and the students t-test value, underscoring the nanocomposite’s effectiveness across diverse sample matrices.