عنوان مقاله [English]
Background and objective: Industrialization has led not only to an increase in water demand, but also to an increase in water pollution due to the discharge of polluted industrial wastewaters with high salt content, and the organic compounds such as phenol into the water bodies.
This study aimed to investigate the efficiency of electrocuagulation and electro-Fenton processes in phenol removal from saline wastewater using Taguchi exprimental design method.
Material and methods: This experimental study was performed in a reactor (1 liter) with synthetic phenolic saline wastewater. In this study for electrocoagulation process, the effects of five operation parameters on phenol removal efficiency including reaction time (20-80 min), electrolyte (1-4%), pH (3-5-7-9), initial phenol concentration (500-1000-1500-250 mg/L) and current density (4-16 mA/cm2) were investigated in four levels by Taguchi L16 orthogonal array. Also for electro-Fenton process, the effects of six operation parameters on removal efficiency in five levels including reaction time (20-80 min), electrolyte (0-4%), pH (2-3-4-6-8), initial phenol concentration (250-500-1000-1500-2000), current density ( 0-16mA/cm2) and hydrogen peroxide (50-300mg/L) were evaluated by Taguchi L25 orthogonal array. The concentration of phenol was determined according to the estandard method in spectrophotometric wavelength of 500 nm.
Results: Experimental data showed that the optimum phenol elimination condition in electrocuagulation process was initial phenol concentration of 250 mg/L, pH = 5, electrolyt = 3%, curent density of 8 mA/cm2 and reaction time of 60 min. The most influential factor in removal efficiency was the initial concentration (63.2%), and the lowest effect belonged to the electrolyt (4.2%).
The optimum phenol removal condition for electro-Fenton process was initial concentration of 250 mg/L, pH:3, electrolyt:2%, hydrogen peroxide:150 mg/L, current density of 8 mA/cm2 and 20 mine contact time. The most influential factor in elimination efficiency was the curent density (29.12%), and the lowest influence on response variable belonged to the reaction time (3.08%).
Conclusion: This study showed the electro-Fenton process was effective in the removal of phenolthat can be used as an appropriate process in wastewater treatment.