부산대학교 도서관

The present work describes the photo-, electro-, and photo-electrooxidation of tetracycline hydrochloride (TCH). We investigated the influence of current density (j), pollutant concentration ([TCH]), and the anode materials, a self-doped titanium nanotubes (SDTNT) and a commercial dimensionally stable anode (DSA®) with a nominal composition of Ti/Ru0.3Ti0.7O2. Pollutant degradation was monitored by molecular absorption spectroscopy on ultraviolet and visible (UV/Vis). The chemical oxygen demand (COD) analysis was carried out to evaluate the degree of mineralization using the best experimental conditions. The synergistic factor (S) was assessed for photo-electrooxidation, to verify whether there was synergism between different approaches. Although, SDTNT electrode with the j = 30 mA cm-2 showed the highest TCH percentual degradation (84.13%) and the faster kinetic constant (k = 0.0173 min–1) degradation of [TCH] = 200 mg L-1, the j = 15 mA cm-2 showed to be the most adequate among the three current densities investigated, presenting 62.30% of TCH degradation and k = 0.0086 min-1; in addition, this j = 15 mA cm-2 preserved the nanotube integrity. A smaller tetracycline concentration ([TCH] = 20 mg L-1) showed a great increment in degradation, achieving 96.20% and a k = 0.026 min-1. The photo-electrooxidation showed the best efficiency, achieving more than 97% degradation in 90 min, k = 0.02955 min-1. Furthermore, photo-electrooxidation approaches have demonstrated a positive value of S, wich indicates that a synergistc effect occurs. SDTNT electrode showed, both in electro and in photo-electrooxidation, an efficiency much higher than DSA®. TCH photo-electrooxidation SDTNT showed the highest COD abatement (80.63%) and mineralization current efficiency (MCE% = 98.22%). Therefore, the PE with SDTNT showed the best global efficiency for TCH photo-electrooxidation.