Lead removal from aqueous using carbon nanomaterials and reuse of the lead-loaded adsorbent as a filler material in cement production

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 Pb^2+-CNPs can be a promising material for cement production when its quantity exceeds 1.2 %.