Activated carbon nonwoven nanofibers (ACNN) mat derived from polyacrylonitrile was manufactured through the electrospinning method followed by thermal treatment steps. The ACNN ability to adsorb Pb(II) from a liquid solution was evaluated. The fabricated ACNN was characterized using Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), and Brunauer–Emmett–Teller (BET). The resulting ACNN exhibited nanofibers with a diameter of 530 nm and a surface area of 550 m2/g. Various adsorption experiments were performed in batch scale to study the impact of factors like contact time, initial Pb(II) ions concentration, and pH. At pH 5, ACNN achieved a removal efficiency of 98% of Pb(II). The equilibrium data for Pb(II) ions was analyzed using the Freundlich and Langmuir isotherm models. Both kinetic models (pseudo-first-order and pseudo-second-order) and isotherm models (Langmuir and Freundlich) were tested. Results revealed that the Langmuir model accurately described the adsorption isotherm of Pb(II) with a maximum capacity of 15.72 mg/g. Data analysis suggested that the pseudo-second-order model better represented the kinetic adsorption behaviour of Pb(II).