Ti4O7-C3N4 anode with a low charge transfer resistance value for degradation of imidacloprid in actual wastewater

Imidacloprid (IMD) is a kind of neonicotinoid insecticide, which is widely used in the agricultural production. There are few reports on electrocatalytic degradation of IMD with the low concentration. In this study Ti 4 O 7 -C 3 N 4 electrode was employed for the first time to electrocatalytically degrade low concentration IMD. Compared with pure Ti 4 O 7 electrode, the oxygen evolution potential was increased from 1.84 V to 2.50 V, the charge transfer resistance (R ct ) was reduced by 66.05 %, and the oxygen vacancies were increased by 2.5 times compared to the original Ti 4 O 7 . Especially, the R ct for Ti 4 O 7 (5.45 Ω·cm 2 ) was only 1/7 of that for boron-doped diamond (BDD) (38.89 Ω·cm 2 ). IMD degradation ratio was up to 98 % in only 1.256 min (75.360 s) using a Ti 4 O 7 -C 3 N 4 . When SongShan Lake water, Wanjiang water, and secondary effluent were treated, the degradation radios of IMD were 70.30 %, 72.33 % and 81.12 %, respectively. In the presence of Cl − coexisting ions, no disinfection by-product of ClO 4 − was detected, which is an advantage for Ti 4 O 7 -C 3 N 4 compared with BDD. The first and 48th degradation ratios were 99 % and 97 %, respectively, indicating the good stability of Ti 4 O 7 -C 3 N 4 . The development of Ti 4 O 7 -C 3 N 4 provides a stable, low energy consumptions and no secondary pollution anode for the treatment of actual wastewater.