Biosorption of heavy metals by the eggshell of laying hen

Abstract

The removal of metallic ions is a difficult task due to the high cost of the treatment methods, which has contributed to the intensification of research by alternative adsorbent materials of low cost and that can be reusable, having their added value to the adsorption process. Thus, in this study aimed the potential use of eggshell as an alternative biosorbent for the removal of metallic ions in wastewater. Specifically, the adsorption isotherms for the copper (II), chromium (III), nickel (II) and zinc (II) metal ions were determined using the Langmuir and Freundlich models. To perform the studies, solutions containing metal ions in various concentrations were added to eggshells of laying hens, kept under orbital agitation for 24 hours at 25ºC and, subsequently filtered for determination in atomic absorption spectrophotometer, the equilibrium concentration of ions. According to the results, it is concluded that both the Langmuir model and the Freundlich model adequately described the adsorption of the copper, chromium, nickel and zinc ions by the ground egg shell; the maximum adsorption capacity for zinc, nickel and chromium copper ions was 25.4291; 6,7354; 9.7928 and 6.7283 mg g-1, respectively; the affinity sequence in the adsorption of the metal ions was Cu> Ni> ZnCr; the eggshell presented potential for the removal of metallic ions, and it can be used in effluent treatment systems.