Efficient electrochemical removal of 5-fluorouracil pharmaceutical from wastewater by mixed metal oxides via anodic oxidation process.

Nowadays, the entry of organic compounds into water resources is one of the leading global concerns due to the lack of water resources and rapid population growth. In this research, anodic oxidation (AO) method was used to remove 5-fluorouracil (5-FU) from aqueous solutions via Ni/RuO2 and Ti/IrO2-TiO2-RuO2 electrodes as cathode and anode, respectively. For this purpose, the characterization analysis of the electrodes, including X-ray diffraction, scanning electron microscopy, energy dispersive X-ray, and atomic force microscopy were performed. The electrochemical performance of the anode was investigated via cyclic voltammetry analysis. Then, the effect of operational variables, including applied current (mA), initial pH of the solution, initial 5-FU concentration (mg/L), and process time (min) on the 5-FU removal efficiency under the AO process was evaluated via artificial neural network (ANN) modeling. The results revealed that the maximum 5-FU removal efficiency was 96.96%. The applied current intensity, pH, initial 5-FU concentration, and process time were 300 mA, 5, 20 mg/L, and 140 min, respectively. Moreover, the investigation of 5-FU removal by-products and mineralization efficiency of the AO process was carried out via gas chromatography-mass spectrometry and total organic carbon analysis, respectively. The total organic carbon mineralization efficiency was 84.80% after 6 h of reaction time. The reusability and stability of the Ti/IrO2-TiO2-RuO2 anode on 5-FU removal efficiency were measured and showed an approximately 5% decay in 5-FU removal efficiency after eight consecutive runs. The overall results and analysis confirmed this method is capable of removing 5-FU through Ti/IrO2-TiO2-RuO2 anode and Ni/RuO2 cathode from aqueous medium.

Ta2O5-incorporated in photoinduced electrocatalyst of TiO2-RuO2 decorated by PPy-NrGO nanocomposite for boosting overall water splitting.

In the current work, the heterostructures highly PEC activity photoelectrodes composed of mixed metal oxides (TiO2-RuO2-Ta2O5 (TRT)), polypyrrole- N doped reduced graphene oxide (PPy-NrGO) were prepared by electrodeposition of PPy-NrGO films on the TRT- coated titanium (Ti) plates as substrates. The TRT coatings were deposited on Ti plates via the sol-gel technique. The effects of the Ta2O5 molar ratios were followed using physical and PEC measurements. Morphology studies showed that the surface structure of photoelectrodes alters remarkably by changing the Ta2O5 content in the mixture of metal oxides. TRT/PPy-NrGO photoelectrodes indicated to have a decreasing impact on the charge transfer resistance at the photoelectrode/electrolyte interfaces. The overall PEC water splitting performances of photoelectrodes were compared by measuring photocurrent density at 0 and 1.23 V vs. RHE, Tafel slopes, charge carrier density, stability, hydrogen evaluation reaction (HER) and oxygen evaluation reaction (OER) efficiencies. The highest HER (43.68% at -0.4 V) and OER (17.51% at 0.45 V) efficiencies were obtained in photoelectrodes comprising of 20 mol% Ta2O5 which possessed charge carrier density (5.9 × 1018) of about 1.7 times higher than that considered for TRT (0%)/PPy-NrGO with no Ta2O5 in the mixture of metal oxides.