Removal of Lead (II) by Chitosan from Aqueous Medium

A waste from the seafood industry, prawn shells, has been used as a water purifier for removing metal ions from water. Chitosan in the presence of natural organic matter obtained from prawn shells waste was used to remove lead from water. The metal uptake by chitosan was successful and rapid and the effect of pH was not prominent. The sorption occurred primarily within 10 minutes. The chitosan surface is not homogeneous, and the adsorption process should be complicated. The sorption of lead by chitosan in prawn shell waste is accomplished by ion exchange and chelating mechanisms. Both the Langmuir and Freundlich isotherms can adequately describe the sorption mechanism. Various anions like chloride, bromide, fluoride, acetate, sulfate, nitrate, and phosphate were found to have a very small effect on the capacity of the chitosan for uptake of lead. Its very high sorption capacity and relatively low production cost and high biocompatibility make chitosan an attractive sorbent for the removal of lead from waste streams.