Study of kinetics and adsorption equilibrium employing chemically modified coconut shell for the removal of Pb(II) from synthetic bath

Abstract

Currently, the industrial sector that employs lead metal in its production, such as the manufacture of cable linings, building elements, pigments, soft welds, and ammunition has caused great contamination in industrial effluents. Faced with these problems, several methods have been applied to reduce the concentration of this toxic metal. The objective of this work is to obtain a low-cost biosorbent with a capacity to remove Pb(II) ions. The modification was through a controlled polymerization reaction in sulfuric medium employing formaldehyde as the starting reagent. The Langmuir, Freundlich, and Temkin models adequately described the adsorption process. They indicated that the modified adsorbent removed Pb (II) with good efficiency and performance. The adsorption capacity of the biosorbent was found to be 120.48 mg.g-1 which is higher or comparable to the adsorption capacity of various adsorbents reported in literature. The adsorption kinetics indicated that equilibrium was reached within 30 min for the conditions studied and that intrapore diffusion is the limiting step of the Pb (II) adsorption process. The results indicated that CCFP has the high potential for removal of Pb (II) in water.