Title : Synthesis and characterization of carbon dots coated Al2O3 nanofibers nanocomposite for Pb2+ ion adsorption and reuse for latent fingerprint detection
This study reports a novel approach of reusing the spent adsorbent Pb2+-CDs/Al2O3NFs nanocomposite for latent fingerprint detection after removing Pb2+ ions from aqueous solution. CDs/Al2O3NFs was prepared by using CDs and Al2O3NFs as precursors. The prepared nanocomposite was then characterized by using UV, FTIR, Fluorescence, XRD, SEM, TEM, EDS, Zeta potential, XPS. The size of the CDs was 51.18 nm. The synthesized CDs/Al2O3NFs nanocomposite has proven to be a good adsorbent in Pb2+ removal from water with optimum pH 6, dosage 0. 2 g / L. The results were favoured by Freundlich models rather than the Langmuir, which was indicated the linear fit of Freundlich models with (R2 = 0.9896). This adsorption was related to the multilayer adsorption processes of Pb2+ ions on the CDs/Al2O3NFs nanocomposite surface. The adsorption capacity of CDs/Al2O3NFs nanocomposite showed the best removal of Pb2+ ions with qm = (177. 83 mg/g), when compared to the previous reports. This adsorption followed the pseudo-second order kinetics and intra particle diffusion processes. ?G and ?H values indicated spontaneity and the endothermic nature of the adsorption process. CDs/Al2O3NFs nanocomposite therefore showed potential as an effective adsorbent. Furthermore, the metal loaded on the adsorbent Pb2+-CDs/Al2O3NFs has proven to be sensitive and selective for latent fingerprint (LFP) detection on various porous substrates. Hence Pb2+- CDs/Al2O3NFs nanocomposite can be reused as a good fingerprint labelling agent in LFP detection so as to avoid secondary environmental pollution by disposal of the spent adsorbent.