Search

In the present work, treatability studies were carried out with oil refinery wastewater (effluent from the secondary treatment) using electrooxidation (EO) process employing two mixed oxide anodes: SnO2–RuO2–IrO2|Ti and IrO2–Ta2O5|Ti. Both electrodes' performance were compared by their capacity to generate active chlorine in a synthetic solution and organic matter mineralization of a sample with an average phenol (C6H6O) concentration of 100 mg L−1. Before degradation experiments, surface analysis, and linear sweep voltammetry tests were performed. SnO2–RuO2–IrO2|Ti anode yielded higher active chlorine, reaching an average concentration of 340 mg L−1 at 90 min of electrolysis and 25 mA cm−2. On the other hand, IrO2–Ta2O5|Ti anode only generated an average concentration of 200 mg L−1 at 90 min and 40 mA cm−2. Regarding the degradation experiments, SnO2–RuO2–IrO2|Ti anode showed the highest dissolved organic carbon removal, ranging from 26% to 40%. In addition, through a three‐dimensional excitation–emission matrix fluorescence analysis, it was possible to elucidate the degradation of C6H6O and some possible polycyclic aromatic hydrocarbons present in the effluent. The results suggested that 65%–90% of the hydrocarbons and C6H6O present in the effluent were degraded with the SnO2–RuO2–IrO2|Ti anode applying 25 mA cm−2 within the first 30 min of electrolysis, reaching almost 99% degradation at 90 min. The EO process using SnO2–RuO2–IrO2|Ti can be an alternative for tertiary treatment of oil refinery wastewater for degradation and mineralization of the remaining organic matter of secondary effluents (biological processes) via active chlorine species. [ABSTRACT FROM AUTHOR]

One of the most widely used antibiotics is amoxicillin (AMX), which is the most widely used in humans and animals, but it is discharged metabolically due to its indigestibility. Conventional biological and physicochemical methods for removing AMX from water are not enough to mineralize it; it is only concentrated and transferred to produce new residues that require further processing to remove the new residues. In this research, naked and modified surfaces with TiO2 nanotubes (TiO2,nt) electrophoretically modified with PbO2, IrO2, RuO2, and Ta2O5 were used to evaluate their efficiency in the electrochemical degradation of AMX in acid media (0.1 mol L-1 H2SO4). After their comparison, Pb-Ta 50:50|TiO2,nt|Ti showed the highest removal efficiency of AMX (44.71%) with the lowest specific energy consumption (8.69 ± 0.78 kWh Kg COD-1) and the average instant current efficiency of 26.67 ± 9.19%, in comparison with the others naked and modified surfaces of TiO2,nt∣Ti. [ABSTRACT FROM AUTHOR]