Application of Azolla filiculoides Biomass for2-Chlorophenol and 4-Chrorophenol Removal from Aqueous Solutions

Background and purpose: the 2-chlorophenol (2-cp) and 4-chlorophenol (4-cp) are phenolic compounds which they may have adverse effects on human and environment. therefore, the removal of these compounds is necessary from water and wastewater. the aim of this study is the investigation of 2-cp and 4-cp removal by using azolla filiculoides biomass.materials and methods: the azolla biomass was sun dried, crushed and sieved to particle sizes in range of 1-2 mm. then treated with 0.1m hcl for 5h followed by washing with distilled water and it used as adsorbent. the residues concentration of 2-cp and 4-cp was measured by spectrophotometer in ?max of 274 and 280 nm, respectively.results: the solute removed increased with increasing of contact time. the equilibrium time for 2-cp and 4-cp is 90 and 75min, respectively. the removal efficiency of 4-cp is more than 2-cp. an increase in initial concentration of both compounds can lead to decrease the removal efficiency of them. the optimum ph to remove the both compound is 5. the equilibrium data is best fitted on langmuir isotherm and the adsorption kinetic model follows pseudo-second model.conclusion: the results indicated that azolla is an effective adsorbent for 2-cp and 4-cp removal from water and wastewater.