Adsorption of cadmium (Cd) and lead (Pb) using powdered activated carbon derived from Cocos Nucifera waste: A kinetics and equilibrium study for long-term sustainability

Abstract

In this research, the activated carbon was prepared using burnt Coconut (Cocos Nucifera) shell and was used as an adsorbent in the removal of toxic heavy metal ions of lead (Pb) and cadmium (Cd) from the aqueous solution using batch adsorption study. Cocos Nucifera was initially collected in the forming shell and then it was crushed in the form of granular. The carbon shell's surface has been modified with an oxidizing agent such as sulphuric acid or nitric acid to increase the shell's adsorption capacity. The effect contact time, pH, temperature, initial concentration, and adsorbent dosage level were analyzed. The result shows that the optimum pH was 6, and the capacity of adsorption was affected by the temperature. The efficiency of the adsorption rises with an increment in temperature. In addition, the characteristics of the adsorbents were studied by making use of SEM, FT-IR, and Energy Dispersive X-ray Analysis (EDX). The adsorption isotherm study was carried out using Langmuir and Freundlich isotherm model, and it shows the charcoal/carbon shell adsorption followed the Langmuir isotherm model. The modeling result of the kinetic model study indicates that the adsorption mechanism of lead (Pb) and cadmium (Cd) process of adsorption were fitted with a pseudo-second-order equation.