Evaluation of the Removal of 2،4 Dichlorophenol by Chitosan from Aqueous Solutions

2¡4 dichlorophenol (DCP), one of the most chlorophenol compounds family with highly toxic effect, exists in agricultural areas, chlorinated waters, discharging wastewater of pulp industries and paper factories. Chlorophenols can cause damages to the kidneys, liver, pancreas and weaken the central nervous system (CNS). In the current study we would evaluate the adsorption of DCP by chitosan in aqueous environments.
In this study we evaluated the effect of operational parameters such as time (15-90min), pH values (3-9), initial concentration of DCP(15-100mg/l)and the dose of chitosan (0.1-0.9g) in a batch reactor. A spectrophotometer at wavelength of 280nm was used to measure the concentration of DCP. Freundlich and Langmuir isotherm models and Pseudo-first order kinetic models and Pseudo-second-order kinetic was drawn by using of the results obtained in the absorption process.
Equilibrium time in the adsorbtion process was estimated to be 75 minutes (DCP Concentration- 15mg/l, Chitosan Concentration – 0.5g and pH- 6.5) with 76% removal efficiency. PH=3 was calculated as the optimal PH in absorption process (DCP Concentration- 15mg/l, Chitosan Concentration- 0.5g and Time Equilibrium-75 min) with efficiency 79% and the value of efficiency decreased by increasing PH. In 15 mg/l concentration of DCP maximum adsorption with an efficiency of 79% was observed. (Chitosan Concentration – 0.5g, Time Equilibrium -75 min and pH-3) and the maximum 87% adsorption efficiency of DCP was observed at the 0.08mg/l absorbent dose of chitosan. (DCP Concentration - 15mg/l, time equilibrium-75 min and pH=3). Adsorption process follows of Freundlich isotherm with correlation coefficient of 0.9599 and the pseudo second order kinetic model with correlation coefficient of 0.9649.
According to results of the study, chitosan can be used to remove of DCP from industrial wastewater due to of its perfect characteristics such as biodegradability, resurgent ability, low cost and adsorption acceptable efficiency.