Removal of heavy metals from their aqueous solutions through adsorption onto natural polymers

Commercial sodium alginate was converted into water insoluble material through a very simple acidification treatment with alcoholic HCl solution. The so-obtained acidified sodium alginate (ASA) was found to exhibit complete water insolubility and to have a carboxyl content of 465 mequi./100 g sample. The ASA was used to remove Zn (II) ions from their aqueous solutions and different factors affecting the adsorption of Zn (II) ions onto ASA, like, pH, adsorbent dose, agitation time, and adsorbate concentration were extensively studied. Adsorption of Zn (II) ions onto ASA was found to be pH-dependent and maximum adsorption was obtained at pH 6.