Photoassisted electrochemical degradation of an azo dye using Ti/RuO2 anode and carbon nanotubes containing gas-diffusion cathode

• Photoassisted electrochemical (PE) degradation of a di-azo dye under recirculation mode.
• Noticeable decrease in required electricity by photoassisted electrochemical system.
• Application of Ti/RuO2 anode and cathode containing carbon nanotubes in PE process.
• Study of the effect of operational parameters on efficiency of PE process.

A photoassisted electrochemical system was utilized for degradation of a di-azo dye under recirculation mode. Experiments were performed with active titanium/ruthenium oxide (Ti/RuO2) anode and cathode containing carbon nanotubes (CNTs). Transmission electron microscopy image of CNTs revealed that they had an inner and outer diameter of 6 nm and 22 nm, respectively. Degradation efficiency of DB129 by photolysis, electrochemical oxidation and photoassisted electrochemical processes was 29.29, 37.19 and 92.03%, respectively at 90 min of processes. TOC results indicated that 93.36% of organic substrates were mineralized after 360 min of photoassisted electrochemical process and some degradation intermediates were identified by GC–MS.