TEHRAN (INIC)- Researchers at University of Tabriz, northwestern Iran, succeeded in removing 93.8% of dye pollutant substances from polluted water by using carbon nanotubes and visible light.

Electro-Fenton process is extensively studied in order to remove pollutants from water. The slow rate of the process, by itself, results in the low efficiency and high cost of the process. Therefore, researchers in University of Tabriz carried out a research in order to speed up and boost the efficiency of the process.

"Various methods are used for the removal of dye pollutants from water. One of the methods is the irradiation of UV to water in addition to electro-Fenton process, which is known as photoelectro-Fenton," Mahmoud Zare'i told the news service of Iran Nanotechnology Initiative Council.

"The equipment required for the production of UV to be used in a photoelectro-chemical process is expensive. Laboratory electrochemical oxidation reactions can change to a useful and successful commercial and applicable method for water purification if the irradiation of UV is replaced by the radiation of the visible light," he continued.

Elaborating on the procedure of the research, Zare'i stated, "We used carbon nanotube-PTFE electrode as cathode and platinum electrode as anode for the electro-Fenton process. Then, we added a desirable amount of potassium oxalate to the solution in order to increase the efficiency of the reaction, and started the irradiation of the visible light by using a 6W lamp. In addition, we used response surface methodology in order to decrease the number of experiments and to optimise the experiment conditions."

The comparison between the results obtained from the processes of electro-Fenton, photoelectro-Fenton, and electro-Fenton with visible light catalyzed by oxalate shows that 93.8% of dye pollutant substances are removed quickly in a determined period of time by electro-Fenton/oxalate/visible light process, while the corresponding efficiency of photoelectro-Fenton and electro-Fenton processes at the same period of time are 35% and 29.8%, respectively.

It must be pointed out that University of Tabriz is in the vanguard of such studies in this field.

The research has been published in detailed form in Desalination, vol. 258, pp. 112-119, 2010.