Insight into electrochemical degradation of Cartap (in Padan 95SP) by boron-doped diamond electrode: kinetic and effect of water matrices

Abstract

In this work, the kinetic electrochemical degradation of Cartap (CT) (in Padan 95 SP) at boron-doped diamond (BDD) electrode was investigated. This study indicated that the degradation of CT underwent both direct and indirect oxidations. Water matrices can either accelerate or inhibit the removal efficiency of CT: adding 15 mM Cl^- improved k_CT from 0.039 min^-1 to 0.054 min^-1 (increased by 38%), while k_CT decreased by 61.5% and 64% when increasing the concentration of HCO₃^- and humic acid (HA) to 15 mM and 15 mg L^-1, respectively. CT degradation was inhibited in the presence of methanol (MeOH) and tert-butanol (TBA) due to the scavenging effect of those chemicals toward reactive species. The contribution of reactive oxidants was calculated as: DET (direct electron transfer) accounted for 15%; •OH accounted for 61.5%; SO₄^•- accounted for 12.8%; ROS (the other reactive oxygen species) accounted for 8.5%. The transformation pathways of major reactive species were established.

Keywords: BDD electrode; Cartap degradation; cyclic voltammetry; kinetic; linear sweep voltammetry; mechanism.