Removal of Chloramphenicol in Wastewater by Electrocatalytic Reduction with Carbon Nanotubes-Modified Electrode

Abstract

In order to develop treatment technique for antibiotics and protect water environmental quality, the carbon nanotubes (CNTs) modified electrode was prepared with surfactant-assisted dispersion, the electrocatalytic reduction ability and kinetic characteristics of chloramphenicol were studied using the modified electrode, and the reduction mechanism was investigated preliminarily. The results showed that CNTs could be effectively dispersed by dihexadecyl phosphate (DHP), and the removal rate of 2 mg·L-1 chloramphenicol reached 97.21% after 24 h reduction using the modified electrode under the optimal ratio of CNTs to DHP and the modified amount of CNTs dispersion. The kinetic process of the electrocatalytic reduction could be well described by the first-order reaction kinetic model, and the removal rate constant and half-time were 0.1574 h-1 and 4.40 h, respectively. The reduction products were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to reveal the possible reduction pathway, which indicated that the electrocatalysis could not only reduce nitro-group in chloramphenicol, but also further reduce carboxyl group and dechlorination, and thus significantly decrease its toxicity.