Electrochemical sensing and electrochemical advanced oxidation treatment of nevirapine using micro- and nanocrystalline boron doped diamond electrodes

Abstract

Boron-doped diamond (BDD) is an electrode material applied in high end advanced oxidation processes and electrochemical sensing. BDD has a low background current, is robust and has a high affinity for the production of oxidizing radicals. BDD shows better degradation rates compared to competing electrode materials, and can also be used to detect trace amounts of compounds. The surface properties of BDD electrodes, such as the crystal sizes present on the electrode surface and the presence of non diamond content, influence their degradation and sensing performance. Electrochemical advanced oxidation processes using BDD electrodes are one of the methods investigated in literature to remove recalcitrant micro-pollutants from wastewater. Wastewater treatment at present faces a challenge to eliminate micro-pollutants of increasing complexity and toxicity. One of the compounds that could potentially benefit from the application of BDD electrodes in its removal from wastewater and detection in human blood and analogues is nevirapine. Nevirapine (NVP) is an antiretroviral on the World Health Organization’s list of essential medicines, used extensively in HIV treatment. NVP has been detected in wastewater in the continents where it is deployed as treatment, and has shown resistance to ordinary wastewater treatment. The removal of NVP from wastewater and the detection of NVP in human blood are current challenges considered in academic research. NVP has not been used in detection or degradation studies using BDD electrodes before. In this study, two types of electrodes were used to attempt to electrochemically degrade and detect NVP. The application of electrochemical activation in combination with micro-crystalline BDD electrodes for NVP sensing is a promising lead into new research to detect low concentrations of NVP using in-situ electrode cleaning. The results obtained indicate further research into the interaction between NVP and the surface of BDD electrodes as well as electrochemical activation could provide a stable detection method to asses NVP at levels competitive to those reported in literature. The research into degradation of NVP using BDD electrodes indicates the practical challenges the interaction between NVP and BDD surfaces poses, for the removal of NVP from wastewater using electrochemical advanced oxidation processes.