Biosorción en tanque agitado de Cd(+2) y Pb(+2) con cáscara de cacao

Abstract

In the search for cleaner technologies for the treatment of effluents containing heavy metals has directed attention to the biosorption. This study allowed us to address the process of biosorption of 〖Cd〗^(+2)y 〖Pb〗^(+2) in effluents miners through the shell of cacao. It was determined the physical and chemical characteristics of the sorbent and the result obtained was: the shell of cacao has a neutral surface composed primarily by groups aliphatic esters; was also studied the factors affecting this process as are: pH, particle size, contact time, temperature, and the initial concentration of metal. The optimal pH for the biosorption lead is between 4 and 5 and for cadmium was between 5 and 6; with respect to the contact time necessary to eliminate the largest amount of metal ions was 10 minutes, being the result obtained in the removal of both cadmium and lead of 86.92% and 96,74% respectively. It was noted that the temperature does not affect as much as the pH and was determined as the optimal 25℃ to control the demining process; it also analyzed that the shell of cacao has higher affinity for the cadmium by ionic have a radius smaller than the lead thus enabling you to reach the smaller pores; in addition to the increasing concentration, the elimination of cadmium decreased and for the lead increased but not significantly. The experimental data of the biosorption of lead and cadmium in shell of cocoa, reproduced favorably the pseudo second order kinetic model, with coefficients of correlation (R^2) for 〖Pb〗^(+2) of 0,999 and 〖Cd〗^(+2) of 1. Finally in the study of balance the Langmuir model describes the process of adsorption for 〖Cd〗^(+2) and the model of Fleundlich was adjusted better to the experimental data for 〖Pb〗^(+2).