Recent developments in polysaccharide-based materials used as adsorbents in wastewater treatment

The chemical contamination of water from a wide range of toxic derivatives, in particular heavy metals, aromatic molecules and dyes, is a serious environmental problem owing to their potential human toxicity. Therefore, there is a need to develop technologies that can remove toxic pollutants found in wastewaters. Among all the treatments proposed, adsorption is one of the more popular methods for the removal of pollutants from the wastewater. Adsorption is a procedure of choice for treating industrial effluents, and a useful tool for protecting the environment. In particular, adsorption on natural polymers and their derivatives are known to remove pollutants from water. The increasing number of publications on adsorption of toxic compounds by modified polysaccharides shows that there is a recent increasing interest in the synthesis of new low-cost adsorbents used in wastewater treatment. The present review shows the recent developments in the synthesis of adsorbents containing polysaccharides, in particular modified biopolymers derived from chitin, chitosan, starch and cyclodextrin. New polysaccharide based-materials are described and their advantages for the removal of pollutants from the wastewater discussed. The main objective of this review is to provide recent information about the most important features of these polymeric materials and,to show the advantages gained from the use of adsorbents containing modified biopolymers in waste water treatment. (C) 2005 Elsevier Ltd. All rights reserved.