Contribution to the elimination of Linuron by the adsorption process using Chitin and Chitosan biopolymers

Fishing industries generate each year,millions of tons of marine shells rich in chitin. these residues are discharged into the sea or buried in the ground. however chitins have a high economic value due to their physicochemical properties and their industrial and biomedical applications. modern agriculture relies on extensive use of pesticides,which generate a number of risks,specially the contamination of groundwater. studies carried out in scope of loukkos perimeter by inra of tangier showed the presence of residues in groundwater because the uncontrolled and excessive use of pesticides. the aim of this work was to decontaminate waters using chitin and chitosan as adsorbents of linuron,a toxic pesticide widely used as herbicide. chitin is a biopolymer obtained from the shells of shrimp and chitosan was prepared by deacetylation process in alkali media (naoh). characterization of chitin and chitosan was achieved by infrared spectroscopy. linuron adsorption was carried out using the batch method under different experimental conditions such as contact time,ph and pesticide concentration. the adsorption process was followed by in situ uv-spectrophotometric technique in a specially designed adsorption cell. linuron adsorption was characterized by studying the adsorption and desorption kinetics and isotherm. the results show that chitin and chitosan are good adsorbents for the removal of pesticides from aqueous solutions. the quantity eliminated was depended on the initial concentration of linuron,herbicide-adsorbent,contact time and ph of solution. the pesticide adsorption on chitin and chitosan is at its maximum at ph [5,7].the adsorption was described by freundlich and langmuir models and the corresponding isotherms were well fitted both to the two models.