One of the most prevalent forms of organic chemical pollutants in industrial wastewaters are Phenol and phenolic compounds [1]. High concentrations of phenol and phenolic compounds typically are found in aqueous effluents of oil refineries, petrochemical, ceramic, and steel plants, coal conversion processes, phenolic resin and pharmaceutical industries [1-4] . Since phenol and its derivatives are toxic and harmful to living organisms even at low concentrations, they are known as noxious pollutants [4]. The most widely used methods for phenol removal from aqueous solutions are adsorption, chemical oxidation, biological treatment, precipitation, distillation, solvent extraction, ion exchange, membrane processes, reverse osmosis, and electrochemical methods [2,4-6] . However, these methods have some problems such as high cost, low efficiency, and generation of toxic byproducts [6]. On the other hand, electrochemical methods have little or no harmful effects on the environment and electrochemical reactions are more or less independent of the conditions of the wastewater [6].

Electrocoagulation is an alternative technology for wastewater treatment in addition to its other conventional applications. The most important advantages of electrocoagulation compared with other conventional techniques are “in situ” delivery of reactive agents, no generation of secondary pollution, and compact equipment [7]. In this study, electrocoagulation using iron electrodes was conducted to investigate the removal of phenol from aqueous solutions.

The phenol used in the experiments was provided from Merck Chemical Company; it was 98.5% pure. Furthermore, Alginate acid sodium salt from brown algae was purchased from Fluka Biochemical and the synthetic wastewater containing the phenol was prepared using distilled water. pH and conductivity were adjusted to a desired value using 0.1 M HCl and NaOH. The electrolyte (NaCl) concentration of 2 g was kept constant initially. The Plexiglas cell as electrolytic reactor having dimensions of 12 cm × 12 cm × 16 cm with a working volume of about 1.5 L was used to conduct the experiments, and a magnetic stirrer was applied for mixing (200 rpm). Iron sheets with the dimensions of 0.10 m× 0.10 m × 0.002 m were also used as electrodes. Between two tests, electrolytic cell (including the electrodes) was cleaned with 15% (W/V) hydrochloric acid solution. The gap between the anode and cathode was 2 cm. A Singleoutput Adjustable DC Power Supply (MPS-3005D) was used as the power supplier. Retention time, pH, current density, and initial phenol, NaCl, and alginic acid concentrations were selected as parameters. At different time intervals, the samples were taken from the reactor and centrifuged for 30 min at 4000 rpm before analysis. Analyses were performed according to the standard methods for examination of water and wastewater [8]. Briefly, the concentrations of phenol were determined by spectrophotometer (Hach DR2800 spectrophotometer) according to the analysis of the color resulted from the reaction of phenol with 4-aminoantipyrine at 500 nm.