Iranian Journal of

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MicrosoftInternetExplorer4 Background and Objectives:  Presence of humic acids in water resources is important because it is a precursor to disinfection by-products (DBPs) and affects many treatment processes. In this study, we investigated the performance of electrocoagulation process duad with hydrogen peroxide (creating Fenton process) in removal of humic acids (HA) from aqueous environment.
Materials and Methods: The experiments were performed using a 1 L bipolar batch reactor (covered with the aluminum foil) equipped with iron electrodes and connected to electric source having electrical potential 10 V in bipolar mode. First, reactor was filled up using aqueous solution containing 20 mg/L HA. Later, several working parameters, such as initial pH (3, 5, 7, and 8), electrical conductivity produced from adding 1, 1.5, 2 and 3 g/l KCl and reaction time were studied to achieve the highest humic acid removal capacity. To follow the progress of the treatment, hydrogen peroxide (50 mg/l) was added to reactor and then samples of 10 ml were taken at 5, 15, 30, 45, and 60 min and then filtered (0.45 μ) to eliminate sludge formed during electrolysis. Finally, humic acid and iron concentration was measured using TOC analyzer and atomic absorption method respectively.
Results: Results of this study showed that the most effective removal capacities of humic acid (97.19%) could be achieved when the pH was kept 5(KCl 3g/l and reaction time 60 min). The share of Fenton and electrocoagulation process was %7.9 and %92.1 respectively. In addition, our results indicated that the removal efficiency of humic acid with increase of pH and electrical conductivity parameters decreases and increases respectively.
Conclusion: It can be concluded that the Fenton process duad with electrocoagulation process has the potential to be utilized for cost-effective removal of humic acid from aqueous environments.

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MicrosoftInternetExplorer4 Background and Objectives: Phenol is one of the most important organic chemicals presenting in water and other environments. It not only brings about hygienic problems but also results in forming 11 toxic priority pollutants in aqueous environments. Hence, the performance of electrocoagulation process using iron and aluminum sacrificial anodes was investigated for removal of phenol.
Materials and Methods: We used a glass tank in 1.56 L volume (effective volume 1 L) equipped with four iron and aluminum plate electrodes to do experiments (bipolar mode). The tank was filled with synthetic wastewater containing phenol in concentration of 5, 20, 40, and 70 mg/l and to follow the progress of the treatment, each sample was taken at 20 min intervals for up to 80 min. The percent of phenol removal was measured at pH 3, 5, 7, and 9 electrical potential range of 20, 40, and 60 volts and electrical conductivity of 1000, 1500, 2000, and 3000 µs/cm.
Results: It was found that the most effective removal capacities of phenol (95 and 98 %) could be achieved when the pH was kept 7 and 5 for iron and aluminum electrodes, reaction time  80 min, electrical conductivity 3000 µs/cm, initial concentration of phenol 5 mg/l, and electrical potential in the range of 20-60 V.
Conclusion: The method was found to be highly efficient and relatively fast compared with existing conventional techniques and also it can be concluded that the electrochemical process has the potential to be utilized for the cost-effective removal of phenol from water and wastewater.