Efficiency of Electro/persulfate Process by Iron Electrode in Removing Furfural from Aqueous Solution

Background and In oil and petrochemical industries, organic aromatic compounds such as furfural are produced on a large scale. They are degradable or act as a deterrent for biological systems. In order to generate sulfate radical (SO4), persulfate (S2O8 -2, PS) is often activated by heat, UV irradiation and intermediate metals like iron ions. The aim of this study was to investigate the efficiency of activated S2O8 -2 by electrically produced iron using the iron electrode (modern process of electro/ persulfate) for furfural removal. In this study, a lab-scale batch reactor equipped to 4 electrodes and direct power source was used to remove furfural. The effects of key parameters such as pH, voltage, initial concentration of S2O8-2 and furfural on the process were studied. Furthermore, we investigated the changes in pH during the process and the effect of the optimized situation The findings showed that initial pH, S2O8 -2 initial concentration and voltage played an important role in furfural removal. Under acidic situations, an increase in the efficiency was seen, and by raising pH the amount of furfural removal decreased. We observed that 98% of furfural was removed in 60 min (pH=3, voltage=10 V, S2O8 -2 concentration=8.4 mM). When the concentration of furfural was raised, the efficiency declined. At pH=5, 7, 9 and 11 after 60 min, the efficiencies were 66, 53, 48 and 12, respectively. By increasing voltage to 10 V, the highest rate of efficiency was seen. By applying S2O8 -2 separately, after 60 min the efficiency was 39% while at these conditions, the efficiency of the electrochemical process was only 28%. By contrast, electro/persulfate could remove 98 of furfural. The use of S2O8 -2 ion in electrochemical reactors equipped to iron electrode can increase the efficiency of the process. Thus, the application of this novel process could be of great benefit for industrial wastewater plants operators.