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In this study, the production of an eco-friendly curcumin based nanocomposite fingerprint labeling powder is reported for the first time. This powder was prepared from thermal power plant waste known as coal fly ash. 3-aminopropyltrimethoxysilane (APTMS) was covalently interacted with coal fly ash (CFA/APTMS) and curcumin (CUR) was encapsulated onto CFA/APTMS to give a novel and eco-friendly CFA/APTMS/CUR nanocomposite for LFPs detection with the powder dusting method. Several instrumental techniques including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV–visible spectroscopy, fluorescence spectroscopy (FL), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), and transmission electron microscopy (TEM) were used to characterize this nanocomposite. The CFA/APTMS/CUR nanocomposite was applied as a forensic powder for the development of latent fingerprint (LFPs) images on various porous and non-porous substrates. Level 2 (island, origination, bifurcation, termination, fork, dot, and bridge) and Level 3 (sweat pores and shape of triangles, round, and irregular) were the features of the LFP images. Under visible light conditions, the aging LFPs images were clearly detected on an aluminum foil surface using the nanocomposite powder, which had good sensitivity and minimal background interference. Additionally, LFPs images were developed using CFA/APTMS/CUR nanocomposite on leather substrates for belts and shoes in order to confirm the benefits of the nanocomposite's high sensitivity. This nanocomposite improved LFPs images with unique patterns and showed excellent performance on a variety of surfaces for the development of LFPs. These findings therefore proved that the powdered CFA/APTMS/CUR nanocomposite can be effectively utilized for the development of LFPs images at important crime scenes and for the biometric identification of criminal suspects through fingerprint comparison.

This work provides a novel approach to prepare nitrogen-doped carbon nanoparticles (CNPs) coated on a cerium oxide nanorods nanocomposite (N-CNPs/CeO2NRsnC) for the uptake of cadmium (Cd2+) ions and re-using the spent adsorbent, Cd2+-CNPs/CeO2NRsnC for latent fingerprint detection (LFP). N-CNPs were prepared by a thermal method with urea and cabbage powder as precursors. N-CNPs/CeO2NRsnC was developed with N-CNPs and CeO2NRs with a hydrothermal method and characterized by various instrument methods like UV-visible, FT-IR, XRD, BET, XPS, SEM, and TEM. The N-CNPs/CeO2NRsnC had a greater surface area (9.96 m2/g) than N-CNPs (0.64 m2/g). The synthesized N-CNPs/CeO2NRsnC proved to be a good sorbent material to remove Cd2+ from water at a maximum pH 8 and dosage 10 mg/L. The adsorption was spontaneous and endothermic at 25 ºC. In addition, Cd2+-N-CNPs/CeO2NRsnC has been shown to be sensitive and selective for LFP identification on several porous substrates. It is therefore a good labeling agent for latent fingerprint identification in forensic science.

Heavy metals are posing problems in the environment and one of them is lead. The disposal of lead in our water systems comes from industries such as the paint, mining, and electroplating industries. In this study, Carbon nanoparticles (CNPs) were synthesized from carbon soot by using a refluxed method. The CNPs were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction pattern (XRD) Brunauer–Emmett–Teller (BET), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and Transmission Electron Microscope (TEM). Batch adsorption studies were carried out for lead adsorption. Pb2+ uptake fitted well with the pseudo-second-order kinetics model, while the adsorption isotherm fitted best to the Langmuir model, with a maximum adsorption capacity of 67.98 mg/g at 25 °C. The obtained thermodynamic parameters demonstrated that the adsorption of Pb2+ ions by carbon nanoparticles was exothermic and spontaneous. The spent adsorbent was then used in cement production, demonstrating that Pb2+-CNPs can be a promising material for cement production when its quantity exceeds 1.2 %.

Coal fly ash was functionalized and modified with graphene oxide and polyaniline (CFA/GO/PANI nanocomposite) through hydrothermal synthesis, which was used for remediation of hexavalent chromium (Cr(VI)) ions. Batch adsorption experiments were carried out to investigate the effects of adsorbent dosage, pH, and contact time on the removal of Cr(VI). The ideal pH for this work was 2, and it was used for all other studies. The Cr(VI)-loaded spent adsorbent CFA/GO/PANI + Cr(VI) was reused as a photocatalyst for the degradation of bisphenol A (BPA). The CFA/GO/PANI nanocomposite removed Cr(VI) ions rapidly. The adsorption process was best described by pseudo-second-order kinetics and the Freundlich isotherm model. The CFA/GO/PANI nanocomposite demonstrated a high adsorption capacity of 124.72 mg/g for Cr(VI) removal. In addition, the Cr(VI)-loaded spent adsorbent played a significant role in the photocatalytic degradation of BPA with 86% degradation. The reuse of the Cr(VI)-loaded spent adsorbent as a photocatalyst presents a new solution for the reduction of secondary waste from the adsorption process., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)