Novel synthesis of γ-Al₂O₃/carbon hollow nanosphere nanocomposite for the optimal removal of Ni²⁺ ions from wastewater and reuse in blood fingerprint enhancement

This study aimed to solve environmental problems, particularly water quality and escalating crime rates. The carbon hollow nanosphere was prepared from orange peels by a reflux method. The carbon hollow nanosphere was coated with Gamma-aluminium oxide (γ-Al₂O₃ NPs) via the hydrothermal method. The samples were analysed using Fourier-transform infrared spectroscopy, Scanning electron microscopy, Transmission Electron Microscopy, Brunauer–Emmett–Teller, Thermogravimetric analysis, and X-Ray diffraction analysis. The surface area of γ-Al₂O₃/carbon hollow nanosphere nanocomposite was confirmed to be 578,039 m²/g, and the Ni²⁺ ions were analysed using ICP-OES. With a maximum adsorption capacity of 56.980 mg/g and a pH 9, batch adsorption experiments revealed that the uptake of Ni²⁺ ions best fitted the Langmuir adsorption isotherm, and the pseudo-second-order kinetics model effectively described the uptake of Ni²⁺ ions with a higher R² of 0.999. Thermodynamic measurements showed the endothermic and spontaneous nature of the Ni²⁺ ions adsorption using the γ-Al₂O₃/carbon hollow nanospheres nanocomposite. The adsorbent was then used to identify latent blood fingerprints, and it was discovered that Ni²⁺-γ-Al₂O₃/carbon hollow nanosphere generated clear images of blood fingerprints on different substrates.