Search Results (9)

This work examines the possibility of using a PbO₂-based electrode doped with the rare-earth metal holmium in the field of oxygen evolution and the development of an efficient method for the degradation of acetamiprid. Acetamiprid is a widely used insecticide and, as such, it very often reaches waterways, where it can cause many problems for wildlife and the environment. X-ray powder diffraction analysis, Raman spectroscopy, and energy-dispersive X-ray spectroscopy results confirmed the structure of Ti/SnO₂-Sb₂O₃/Ho-PbO₂, while the morphology of its surface was investigated by scanning electron microscopy with energy-dispersive X-ray spectroscopy. Ti/SnO₂-Sb₂O₃/Ho-PbO₂ showed good OER activity in alkaline media with a Tafel slope of 138 mV dec⁻¹. The Ti/SnO₂-Sb₂O₃/Ho-PbO₂ electrode shows very good efficiency in removing acetamiprid. By optimizing the degradation procedure, the following operating conditions were obtained: a current density of 20 mA cm⁻², a pH value of the supporting electrolyte (sodium sulfate) of 2, and a concentration of the supporting electrolyte of 0.035 M. After optimization, the maximum efficiency of removing acetamiprid (10 mg L⁻¹, 4.5 × 10⁻⁵ mol) from water was achieved, 96.8%, after only 90 min of treatment, which represents an efficiency of 1.125 mol cm⁻² of the electrode. Additionally, it was shown that the degradation efficiency is strictly related to the concentration of the treated substance. Full article

This study presents the fabrication of a samarium-doped Ti/Sb-SnO₂/PbO₂ electrode and investigates its applications in polluted water treatment and energy conversion. Physicochemical properties were characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray powder diffraction analysis, and Raman spectroscopy. The Ti/Sb-SnO₂/Sm-PbO₂ electrode showed 2.5 times higher oxygen evolution potential activity than the Ti/Sb-SnO₂/PbO₂ electrode. Density Functional Theory was used to conduct first-principles calculations, and the obtained results indicated that Sm doping enhances the production of reactive oxygen species. The application of the Ti/Sb-SnO₂/Sm-PbO₂ electrode in carbendazim (CBZ) removal was investigated, since CBZ is a fungicide whose presence in the environment, including food, water, and soil, poses a threat. After 60 min of the treatment under optimized working parameters, the degradation rate of CBZ reached 94.2% in the presence of 7.2 g/L Na₂SO₄ with an applied current density of 10 mA/cm² in an acidic medium (pH 4). Of the four investigated parameters, the current density had the most significant influence on the degradation process. At the same time, the initial pH value of the solution was shown to have the least impact on degradation efficiency. These results imply a potential use of the proposed treatment for CBZ removal from wastewater. Full article

Removing high-concentration organic dye from wastewater is of great concern because the hazards can cause serious damage to the environment and human health. In this study, the hybrid dimensionally stable anode (DSA) with a Ce-doped and SnO₂-Sb₂O₅ intermediate layer was fabricated and used for the electro-catalytic oxidation of three kinds of ultra-high-concentration organic dyes. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed the denser surface structure and morphology of the composite Ti/SnO₂-Sb₂O₅/Ce-PbO₂ electrode. Moreover, the electrode exhibited an excellent oxygen evolution potential of 1.58 V. The effect on the removal efficiencies of high concentrations of up to 1 g/L of methyl orange, methylene blue, and neutral red solutions with the above composite electrode was investigated. The research results illustrated that target molecules in the three different dye solutions were rapidly decolorized and decomposed by electro-catalytic oxidation in less than 35 min. Additionally, the degradation process still followed pseudo-first-order kinetics for high-concentration dye solutions. The removal efficiency of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) for the three dye solutions was more than 98%, and the results of the gas chromatography–mass spectrometry (GC-MS) analysis showed that it had the best degradation effects for neutral red, which decomposed more thoroughly. More than 80 h of accelerated life also revealed excellent performance of the composite electrode in the face of high-concentration dye solution degradation. Considering these results, the Ti/SnO₂-Sb₂O₅/Ce-PbO₂ anode could be utilized to treat wastewater containing high-concentration dyes with high efficiency. Full article

Bi³⁺ doped Ti/Sb-SnO₂/PbO₂ electrode materials were fabricated by electrodeposition to improve their electrochemical performance in zinc electrowinning. The surface morphology, chemical composition, and hydrophilicity of the as-prepared electrodes were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle. An electrochemical measurement and an accelerated lifetime experiment were also conducted to investigate the electrocatalytic performance and stability of the electrodes. The results show that the Bi³⁺ modification electrode has an important effect on the coating morphology, the crystal structure, the surface hydrophilicity, the electrocatalytic activity, and the stability. The electrode prepared from the solution containing 2 mmol·L⁻¹ Bi(NO₃)₃ (marked as the Ti/Sb-SnO₂/2Bi-PbO₂ electrode) exhibits the best hydrophilicity performance (θ = 21.6°) and the longest service life (1196 h). During the electrochemical characterization analysis, the Ti/Sb-SnO₂/2Bi-PbO₂ electrode showed the highest oxygen evolution activity, which can be attributed to it having the highest electroactive surface (q_T* = 21.20 C·cm⁻²) and the best charge-transfer efficiency. The DFT calculation demonstrated that the doping of Bi³⁺ leads to a decrease in the OER reaction barrier and an increase in the DOS of the electrode, which further enhances the catalytic activity and the conductivity of the electrode. Moreover, the simulated zinc electrowinning experiment demonstrated that the Ti/Sb-SnO₂/2Bi-PbO₂ electrode consumes less energy than other electrodes. Therefore, it is expected that the Bi³⁺ modified electrode will become a very promising electrode material for zinc electrowinning in the future. Full article

Active granule (WC/Co₃O₄) doping Ti/Sb-SnO₂/PbO₂ electrodes were successfully synthesized by composite electrodeposition. The as-prepared electrodes were systematically characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical performance, zeta potential, and accelerated lifetime. It was found that the doping of active granules (WC/Co₃O₄) can reduce the average grain size and increase the number of active sites on the electrode surface. Moreover, it can improve the proportion of surface oxygen vacancies and non-stoichiometric PbO₂, resulting in an outstanding conductivity, which can improve the electron transfer and catalytic activity of the electrode. Electrochemical measurements imply that Ti/Sb-SnO₂/Co₃O₄-PbO₂ and Ti/Sb-SnO₂/WC-Co₃O₄-PbO₂ electrodes have superior oxygen evolution reactions (OERs) relative to those of Ti/Sb-SnO₂/PbO₂ and Ti/Sb-SnO₂/WC-PbO₂ electrodes. A Ti/Sb-SnO₂/Co₃O₄-PbO₂ electrode is considered as the optimal modified electrode due to its long lifetime (684 h) and the remarkable stability of plating solutions. The treatment of copper wastewater suggests that composite electrodes exhibit low cell voltage and excellent extraction efficiency. Furthermore, pilot simulation tests verified that a composite electrode consumes less energy than other electrodes. Therefore, it is inferred that composite electrodes may be promising for the treatment of wastewater containing high concentrations of copper ions. Full article

In this study, the electrochemical degradation of nitrobenzene (NB) was conducted on the Ti/SnO₂-Sb/Ce-PbO₂ anode with excellent functional performance. The effect of applied current density, electrode distance, pH value and initial concentration on the reaction kinetics of NB was systematically studied. The total organic carbon (TOC) removal rate reached 91.5% after 60 min of electrolysis under optimal conditions. Eight aromatic intermediate products of NB were identified by using a gas chromatography coupled with a mass spectrometer, and two aliphatic carboxylic acids were qualitatively analyzed using a high-performance liquid chromatograph. The electrochemical mineralization mechanism of NB was proposed based on the detected intermediates and the identified key active oxygen specie. It was supposed that the hydroxyl radical produced on an anode attacked NB to form hydroxylated NB derivatives, followed by the benzene ring opening reactions with the formation of aliphatic carboxylic acids, which mineralized to CO₂ and H₂O. In addition, NB was reduced to less stable aniline on the cathode surface, which resulted in actualized mineralization. The successful pilot-scale industrial application in combination with wastewater containing NB with the influent concentration of 80–120 mg L⁻¹ indicated that electrochemical oxidation has great potential to abate NB in practical wastewater treatment. Full article

The porous Ti/Sb-SnO₂/Ni-Ce-PbO₂ electrode was prepared by using a porous Ti plate as a substrate, an Sb-doped SnO₂ as an intermediate, and a PbO₂ doped with Ni and Ce as an active layer. The surface morphology and crystal structure of the electrode were characterized by scanning electron microscope(SEM), energy dispersive spectrometer(EDS), and X-Ray diffraction(XRD). The electrochemical performance of the electrodes was tested by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and electrode life test. The results show that the novel porous Ni-Ce-PbO₂ electrodes with larger active surface area have better electrochemical activity and longer electrode life than porous undoped PbO₂ electrodes and flat Ni-Ce-PbO₂ electrodes. In this work, the removal of Cl⁻ in simulated wastewater on three electrodes was also studied. The results show that the removal effect of the porous Ni-Ce-PbO₂ electrode is obviously better than the other two electrodes, and the removal rate is 87.4%, while the removal rates of the other two electrodes were 72.90% and 80.20%, respectively. In addition, the mechanism of electrochemical dechlorinating was also studied. With the progress of electrolysis, we find that the increase of OH^- inhibits the degradation of Cl⁻, however, the porous Ni-Ce-PbO₂ electrode can effectively improve the removal of Cl⁻. Full article

A novel electrode consisting of a Ti/PbO₂ shell and Fe₃O₄/Sb–SnO₂ particles was developed for electrochemical oxidation treatment of wastewater. Scanning electron microscope (SEM), X-ray diffraction (XRD), the current limiting method, toxicity experiments, and high-performance liquid chromatography were adopted to characterize its morphology, crystal structure, electrochemical properties, the toxicity of the wastewater, and hydroxyl radicals. Acid Red G (ARG), a typical azo dye, was additionally used to test the oxidation ability of the electrode. Results indicated that the 2.5D electrode could significantly improve the mass transfer coefficient and •OH content of the 2D electrode, thereby enhancing the decolorization, degradation, and mineralization effect of ARG, and reducing the toxicity of the wastewater. The experiments revealed that, at higher current density, lower dye concentration and higher temperature, the electrochemical oxidation of ARG favored. Under the condition of 50 mA/cm², 25 °C, and 100 ppm, the ARG, Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiency reached 100%, 65.89%, and 52.52%, respectively, and the energy consumption and the current efficiency were 1.06 kWh/g COD, 8.29%, and energy consumption for TOC and mineralization current efficiency were 3.81 kWh/g COD, 9.01%. Besides, the Fe₃O₄/Sb–SnO₂ particles after electrolysis for 50 h still had remarkable stability. These results indicated that the ARG solution could be adequately removed on the 2.5D electrode, providing an effective method for wastewater treatment. Full article

Porous Ti/SnO₂–Sb₂O₃/PbO₂ electrodes for electrocatalytic oxidation of chloride ions were studied by exploring the effects of different operating conditions, including pore size, initial concentration, current density, initial pH, electrode plate spacing, and the number of cycles. In addition, a physicochemical characterization and an electrochemical characterization of the porous Ti/SnO₂–Sb₂O₃/PbO₂ electrodes were performed. The results showed that Ti/SnO₂–Sb₂O₃/PbO₂ electrodes with 150 µm pore size had the best removal effect on chloride ions with removal ratios amounting up to 98.5% when the initial concentration was 10 g L⁻¹, the current density 125 mA cm⁻², the initial pH = 9, and the electrode plate spacing 0.5 cm. The results, moreover, showed that the oxygen evolution potential of 150 µm porous Ti/SnO₂-Sb₂O₃/PbO₂ electrodes was highest, which minimized side reactions involving oxygen formation and which increased the removal effect of chloride ions. Full article