Nickel and Cobalt Adsorption on Activated Coal of Coconut Shell

Abstract

The present study explores the ability of activated carbon of coconut  shell  for the removal of nickel(II) and cobalt(II)under different experimental conditions from modeled sulfate solutions.Experiments were carried out in order to obtain the adsorption capacity and the adsorption rate.  It was developed for 23 factorial design, considering as main effect initial concentration of solution, pH and dose of adsorbent. The adsorption capacity of Co (II) reached values  between 0,70 and 9,94 mg/g; Ni (II) reached values  between 2,62 and 98,21mg/g. The initial concentration of the solution and the dose of adsorbent had significant influence on the
adsorption capacity.  The pH exerted a  significant influence in the percentage of adsorption. The adsorption capacity was favored at higher initial co ncentration level and lower level of dose of adsorbent, at pH 5; the adsorption percentage was high (99, 6 % cobalt and 98,21 % nickel). Adsorption isotherms were obtained at pH 1, 2, 3 and 5; adsorption isotherms of Co(II) had a good fit to the Langmuir m odel, the maximum adsorption capacity of between 33,33 and 71,43 mg/g; adsorption was very favorably with high affinity adsorbate -   adsorbent. Adsorption isotherms of Ni(II) had better fit to the Freundlich model, showing a
favorable adsorption, with maxim um adsorption capacity of 15,86 and 17,60 mg/g at pH 3 and 5.