Physicochemical Behavior of Penaeuse semisulcatuse Chitin for Pb and Cd Removal from Aqueous Environment

A beta type-chitin was produced from the shell of Penaeuse semisulcatuse shrimp for removal of lead and cadmium from the aqueous environment. Full physicochemical properties of the chitin (FTIR, SEM, mapping, XRD, EDX, AFM, and TGA-DTG) were obtained. Effects of solution pH, chitin dose, metals concentration, and contact time on the lead and cadmium adsorption were assessed. The solution pH had a great influence on the metal removal. Pseudo-first and pseudo-second order models were used to evaluate the kinetic behavior of metals adsorption by P. semisulcatuse chitin. Freundlich isotherm model was slightly better than the Langmuir model to describe the adsorption data. The R-L value (obtained from the Langmuir model) for the adsorption of lead and cadmium was calculated to be 0.027 and 0.133, respectively, which showed the metals adsorption process by the chitin is desirable. The maximum adsorption capacity of lead and cadmium by P. semisulcatuse chitin was determined 13.14mg/g and 19.15mg/g, respectively. To desorb the adsorbed-metal from the chitin, the 1M HNO3 solution was applied and the heavy metals desorption was suitable (90%). The half life (t(1/2)) factor in the adsorption of Pb and Cd onto chitin was calculated 2.817min and 3.876min, respectively.