Relationship between substrate type and BDD electrode structure, performance and antibiotic tetracycline mineralization

Abstract To comprehensively understand the relationship between substrate type and boron doped diamond (BDD) electrode structure, performance and antibiotic tetracycline mineralization, this work made a systematic evaluation of BDD electrodes prepared by the same process but based on different substrates, namely Si/BDD, Ta/BDD, Nb/BDD and Ti/BDD, in terms of microstructure, electrochemical properties, antibiotic tetracycline mineralization and accelerated service life. The results show that the physical and chemical properties of substrates have significant impacts on BDD film growth and microstructure. The substrate and film surface characteristics determined the physicochemical properties of BDD electrode. The growth rate of BDD film follows the sequence order as Si > Ta > Nb ≫ Ti. Ti/BDD electrode shows the higher oxygen evolution potential, lower background current, smaller electron transfer resistance, lower surface activity and shorter service life. Tetracycline can be completely removed by direct electron transfer or free radical mediated oxidization. On Ti/BDD electrode tetracycline removal and current efficiency are the second only to Si/BDD and the lowest electricity consumption can be obtained. Nb/BDD electrode shows slightly better performance than Ta/BDD electrode. Furthermore, the anode failure mode of Ti/BDD electrode was revealed.