Adsorption Isotherms and Kinetics Studies of Lead on Polyacrylonitrile-Based Activated Carbon Nonwoven Nanofibres

Activated carbon nonwoven nanofibres (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, Fourier-transform infrared spectroscopy, and Brunauer-Emmett-Teller method. The resulting ACNN exhibited nanofibres 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 analysed using the Freundlich and Langmuir isotherm models. Both kinetic models (pseudo-first-order and pseudo-second-order) and isotherm models 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).