Xiaoliang Li

An improved stable Ti/Sb–SnO2 electrode with high performance in electrochemical oxidation processes

An improved Ti/Sb–SnO2 electrode was fabricated by inserting a specific Sb–SnO2 interlayer between the Ti substrate and the surface Sb–SnO2 coating. Characterization experiments including scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersing spectrum (EDS), accelerated lifetime test, degradation experiment of an azo dye Acid Red G, and cyclic voltammetry (CV) measurement were performed to determine the effect of the interlayer. The results show that the coating on this new electrode is compact and crack-free. The distribution of Sn and Sb elements in the coating exhibits a gradient distribution from the bottom to the top. The high electrochemical oxidation capability of Ti/Sb–SnO2 did not decrease with the insertion of the interlayer. The improved electrode exhibited much higher electrode stability than the conventional Ti/SnO2 electrode. In a 0.5 M H2SO4 solution, at a current density of 200 mA cm−2, the accelerated lifetime of the conventional Ti/Sb–SnO2 was only 0.84 h, which is much lower that of the improved electrode (10.71 h). A possible reason for the electrode stability enhancement is attributed to the change in the electrode deactivation mechanism. In addition, practical service lifetimes were also estimated for the improved Ti/Sb–SnO2 in different media.

High-performance Ti/Sb–SnO2/Pb3O4 electrodes for chlorine evolution: Preparation and characteristics

Chlorine evolution via electrochemical approach has wide application prospects in drinking water disinfection and wastewater treatment fields. Dimensional stable anodes used for chlorine evolution should have high stability and adequate chlorine evolution efficiency. Thus a novel and cost-effective Ti/Sb-SnO(2)/Pb(3)O(4)electrode was developed. The physicochemical and electrochemical properties as well as the chlorine evolution performances of the electrodes were investigated. The electrocatalytic activity and deactivation course of the electrodes were also explored. Results showed that this novel electrode had strong chlorine evolution ability with high current efficiency ranging from 87.3% to 93.4% depending on the operational conditions. The accelerated service life of Ti/Sb-SnO(2)/Pb(3)O(4) electrode could reach 180 h at a current density of 10,000 A m(-2) in 0.5 molL(-1) H(2)SO(4). During the electrolysis process, it was found that the conversion of Pb(3)O(4) into β-PbO(2) happened gradually on the electrode surface, which not only inhibited the leakage of hazardous Pb(2+) ion but also increased the anti-corrosion capacity of the electrode effectively.

Preparation and characterization of PbO2 electrodes modified with polyvinyl alcohol (PVA)

Novel PbO2 electrodes were successfully synthesized with polyvinyl alcohol (PVA) modification through electro-deposition technology. The morphology and crystalline structure of the electrodes were characterized by SEM and XRD, respectively. In addition, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and accelerated life stability testing were also carried out to analyze the chemical state, electrochemical performances and stability of the electrodes. The results showed that PVA could refine the grain size and increase the oxygen evolution potential (OEP). After PVA modification, the predominant phase of the PbO2 electrodes was unchanged and all were pure β-PbO2. Besides, for modified electrodes, the electrode film impedance reduced and the proportion of adsorbed hydroxyl oxygen (Oad) on the electrode increased, implying the fast charge transfer and excellent degradation efficiency for organics. In the process of dye oxidation, the PbO2-2.0 vt% electrode showed the highest electrocatalytic activity for ARG degradation due to its highest OEP and massive Oad. Moreover, the accelerated service life tests revealed that the PbO2-2.0 vt% electrode exhibited the highest stability and the accelerated service life was 329.5 h, which was more than 3 times longer than that of the PbO2-0 vt% electrode (96 h).

Electrochemical oxidation of guaiacol to increase its biodegradability or just remove COD in terms of anodes and electrolytes

To assess the role of electrochemical oxidation as a single mineralization technique or a pretreatment (for biotreatment) of lignin-containing wastewater, Ti/Sb-SnO2 and Ti/Pb3O4 were used as comparable anode materials to degrade the lignin monomer guaiacol. The electrode catalytic activity was examined by cyclic voltammetry. Then the guaiacol degradation was analyzed. Finally, the main intermediates and products were identified. The results show that Ti/Sb-SnO2 is non-selective in treating guaiacol and its intermediates while Ti/Pb3O4 has a weaker ability in degrading the intermediates. A chlorine-containing media is suitable to perform total organic removal with a high rate, but the active chlorine and organochlorine may ruin the follow-up biological treatment. Electrochemical oxidation (EO) pretreatment could save 50–70% electric energy and reduce the burden of subsequent biotreatment. Quinones and dimers are important intermediates that could be used to distinguish the capability of anodes and the function of Cl−.

Electrochemical oxidation of aniline by a novel Ti/TiOxHy/Sb-SnO2 electrode

Abstract Electrochemical oxidation of aniline in aqueous solution was investigated over a novel Ti/TiO x H y /Sb-SnO 2 electrode prepared by the electrodeposition method. Scanning electron microscopy, X-ray diffraction, and electrochemical measurements were used to characterize its morphology, crystal structure, and electrochemical properties. Removal of aniline by the Ti/TiO x H y /Sb-SnO 2 electrode was investigated by ultraviolet-Visible spectroscopy and chemical oxygen demand (COD) analysis under different conditions, including current densities, initial concentrations of aniline, pH values, concentrations of chloride ions, and types of reactor. It was found that a higher current density, a lower initial concentration of aniline, an acidic solution, the presence of chloride ions (0.2 wt% NaCl), and a three-dimensional (3D) reactor promoted the removal efficiency of aniline. Electrochemical degradation of aniline followed pseudo-first-order kinetics. The aniline (200 mL of 100 mg L −1 ) and COD removal efficiencies reached 100% and 73.5%, respectively, at a current density of 20 mA cm −2 , pH of 7.0, and supporting electrolyte of 0.5 wt% Na 2 SO 4 after 2 h electrolysis in a 3D reactor. These results show that aniline can be significantly removed on the Ti/TiO x H y /Sb-SnO 2 electrode , which provides an efficient way for elimination of aniline from aqueous solution.