Agro-based carbon for lead removal from solutions

Abstract

The current study utilizes the carbon derived from the lemon peel (CLP) as an adsorbent to remove Pb (II) ions from solutions. Activation of the lemon peels was carried out by adding 1 part of the lemon peels to 1.8 parts of concentrated sulphuric acid, and well-mixed before heating the mixture at a temperature of 150 °C for 24 hours. The produced material, CLP, was employed for lead adsorption from water. A number of parameters namely, treatment times, pH, and doses of CLP were studied to assess their influence on the removability of Pb (II) by the CLP. The results indicated that the optimum contact time, pH, and dosage values for the best removal of lead were 80 min, 5, and 3 g/L respectively. To analyze the observed data gained from batch equilibrium tests, isotherm models (Freundlich and Langmuir), kinetic models (the pseudo-first-order, and the pseudo-second-order), and inter-particle diffusion using non-linear regression techniques were applied for this purpose. The obtained results proved that the equilibrium data have reasonable and good fitness and correspondence with the Freundlich isotherm models. The highest adsorption capacity and the highest removal percentage for Pb (II) were 32.98 mg/g and 99% respectively at ambient temperature.