Adsorption of cadmium from water using activated carbon derived from Ipomoea Carnea using chemical impregnation

Abstract

Ipomoea Carnea is a wild shrub, and because of its abundance, it was chosen as precursor for making activated carbon. Adsorbent preparation method involved the impregnation of dried precursor with zinc chloride followed by activation at 500°C. Surface morphology of prepared adsorbent was compared with the raw Ipomoea Carnea by Scanning Electron Microscope analysis. Batch adsorption studies were carried out to understand the effect of parameters like, metal initial concentration, contact time, adsorbent dose and pH on percent removal of cadmium. More than 96% removal of Cd(II) was obtained at the adsorbent dose of 0.3 g/L in 20 minutes at pH 6. Experimental data were fitted to isotherm and kinetic models to understand the mechanism of adsorption. Adsorption of Cd(II) onto raw Ipomoea Carnea followed the Langmuir isotherm, whereas adsorption onto activated Ipomoea Carnea followed the Freundlich isotherm. Kinetic study reveal that the experimental data of adsorption of Cd(II) onto activated Ipomoea Carnea followed the second order kinetic.