Background and Aim: Chlorophenols are acidic Organic compounds and priority Pollutants. One of the best ways to removal chlorophenols was using different absorbents . In this study, removal efficiency of ortho- chlorophenol as one of the most common organic contaminants in aquatic environments was investigated with absorption method using activated Fly Ash.

  Materials and methods: In this experimental study, Fly ash of collected from Zarand Power plant was activated by sulfuric acid. Factors affecting in sorbent activation process including temperature, time, amount and concentration of the acid and also factors influencing in the adsorption process were adjusted for optimum conditions. Experiments was followed on real wastewater samples from coal washing plant of zarand . Data was analyzed by SPSS software.

  Results : The sorbent activation was performed in optimized condition acid concentration 1.8 mM, time 5h, temperature 29±2˚C and acid/fly ash ratio 7. Removal efficiency of zarand coal washing plant Effluent at the optimal conditions (pH: 2, adsorbent doze: 1g, time: 3h) was 84.4%.

  Conclusion: In addition to the high efficiency of ortho-chlorophenol absorption because of sorbent activation does not require complex and expensive technology, the adsorbents can be used to remove these contaminants from industry effluent.