Evaluation of removal efficiency of 2-chlorophenol in aquatic environments by modified fly ash

Abstract

Background: Chlorophenols are classified as priority toxic pollutants. These acidic organic compounds present a serious potential hazard for human health and aquatic life. Chlorophenols accumulate in water, soil and air due to high stability, and impart an unpleasant taste and odor to drinking water and can exert negative effects on different biological processes. Among the different methods of removal, adsorption process by low price adsorbents, such as fly ash (FA) is common. Therefore, in this study, the effects of oxidation of FA as modified adsorbent were investigated when the adsorption of 2-chlorophenol (2-CP) was increased. Methods: This experimental study was conducted from March to September of 2013. FA obtained from Zarand power plant (located in Kerman province) was oxidized with potassium permanganate. Effective factors on the oxidation of FA, such as temperature, oxidation time and concentrations of oxidizers were optimized. Raw sewage of Zarand coal washing plant was tested under optimal conditions. All tests were carried out according to the standard methods book for the examination of water and wastewater. Results: Optimal condition for the preparation of oxidized FA was obtained at 70°C, 1 hour, and 1 mM of potassium permanganate concentration. The absorber obtained was able to remove 96.22% of 2-CP under optimized conditions (pH=3, 2 hours, adsorbent dose 0.8 g and room temperature). The removal efficiency of the real wastewater under optimal conditions was 82.1%. Conclusion: Oxidized FA can be used for the removal of this pollutant from industry wastewater due to its high efficiency of removal in real wastewater, it is easy and inexpensive to prepare and could modify the sorbent.

Keywords

• Chlorophenol
• Adsorption process
• Modified adsorbent