Competitive adsorption of metals and organics onto a low cost natural polysaccharide

Metals removal onto a low-cost natural polysaccharide is performed. Firstly, some specific characteristics of adsorbent are determined. Potentiometric titrations of the sorbent have been realised. The values of the point of zero net proton charge (pznpc) and the cation exchange capacity (CEC) deduced from these experiments have given respectively pH=5 and 0.575 meq g(-1). Secondly, sorption of cations from single metallic solution, have been performed and the equilibrium fixation capacities are 0.37 mmol g(-1) for Pb2+, 0.28 mmol g(-1) for Cu2+ and 0.2 mmol g(-1) for Ni2+. In multi-metals solutions of equimolar concentration, Ni2+ ions present the greatest fixation decrease in the presence of the two other cations (-61%), Pb2+ and Cu2+ seem to compete similarly. In the presence of a constant organic load composed of either benzaldehyde, benzoic acid or phenol and expressed as 100 mg l(-1) total organic carbon (TOC), benzoic acid induces the largest reduction of the copper equilibrium fixation capacity (-30%).