Том 55, № 7 (2019)

Existence of an organic compounds, especially aromatic compounds in wastewater is observed as an emerging environmental problem because of their harmful effects on living organisms even at low concentration. Conventional wastewater treatment processes are ineffectual for an elimination of refractory organic compounds. Nowadays, it’s a challenge to reduce negative impact of such hazardous compounds on environment. So, Advanced Oxidation Processes (AOPs) have received more attention over a year of decades towards removal of an aromatic compounds. Among AOPs, Electrochemical Advanced Oxidation Processes (EAOPs), especially “Anodic Oxidation” and “Electro-Fenton,” have revealed good potential for mitigation of pollution caused by the presence of aqueous organic compounds in wastewater. This review has introduced an innovative collection of current knowledge on Electro-Fenton and Anodic oxidation type of processes. Fundamentals of these processes, electrolysers used, reaction mechanisms, experimental parameters affecting these electro-chemical treatment technologies with various applications are discussed in detail. This report also discusses effectiveness of EAOPs for elimination of organic compounds in aqueous systems.

9-Phenyl-9H-carbazole (9P9HC) organic monomer which contains phenyl moiety used as new overcharge protection additive in electrolyte of LiFePO₄ based lithium‑ion batteries (LIBs) was investigated in this paper. The cyclic voltammetry experimental results showed that the 9P9HC monomer could be electro‑polymerized to form a conductive polymer on the cathode surface. Therefore, it could prevent the batteries from voltage run away during overcharge. The charge–discharge tests of the investigated LiFePO₄/C batteries demonstrated that the 9P9HC additive could be control the investigated LIB voltage at the safe value less than 4.2 V. Furthermore, it was notable that 9P9HC has no significant impact on the charge–discharge performance of the investigated batteries at normal charge–discharge condition during 50 cycles.

A highly sensitive melamine electrochemical sensor was successfully constructed by self-assembling based on the composite of chitosan with polyvinyl pyrrolidone-dispersed reduced graphene oxide (CTS-PVP-rGO), gold nanoparticles (AuNPs) and metal-organic framework MIL-101. The characterizations of modified materials and electrodes were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron dispersive X-ray (EDX) spectroscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The results indicated that the sensor of MIL-101/AuNPs/CTS-PVP-rGO/GCE exhibited a high sensitivity and selectivity as well as a good stability and reproducibility for the determination of melamine since CTS-PVP-rGO or AuNPs could enhance the conductivity of the sensor greatly and MIL-101 could promote the adsorption of melamine on the surface of the modified electrode remarkably. At pH 7.0, the scan rate of 100 mV/s and the frequency of 50 Hz, the determination limit of melamine was as low as 5.00 × 10^–11 mol/L with the linear range from 5.00 × 10^–11 to 1.00 × 10^–8 mol/L and the correlation coefficient (R) of 0.996. Based on the electrochemical behavior of melamine on MIL-101/AuNPs/CTS-PVP-rGO/GCE, the possible redox procedure of melamine was put forward. Furthermore, the sensor of MIL-101/AuNPs/CTS-PVP-rGO/GCE was applied to the determination of melamine in milk products and a satisfying result was obtained.

Electrochemical characteristics of fuel cells containing CaZr_0.9Y_0.1O_{3 – δ} film supported by Ni–CaZr_0.95Sc_0.05O_{3 – δ} anode are studied. It is shown that the diffusion of nickel from the electrode-support favors the increase in electronic conductivity of the electrolyte. It is found that to provide sufficiently high transport numbers of ions, the thickness of the CZY electrolyte film should not be smaller than 4 µm. The polarization losses on the anode are concluded to be the main reason for the lower power of fuel cells with thin-film electrolyte.

New nanostructured Pt/(SnO₂/C)-electrocatalyst (20 wt % Pt) is synthesized via platinum chemical deposited onto composite SnO₂/C-support microparticles (4 wt % Sn). The composite support was prepared beforehand using unique method of the tin electrochemical deposition onto disperse carbon black particles. It was shown by X-ray diffraction and transmission electron microscopy that the platinum and tin oxide nanoparticles distributed over the carbon surface are sized 2.4 and 2.9 nm, respectively. Electrochemical measurements showed the obtained catalyst to approach the commercial Pt/C HiSPEC 3000 catalyst (20 wt % Pt) with respect to its mass-activity in the oxygen electroreduction reaction and to be superior thereto as for the electrochemically active surface area, stability in stress test, and activity in methanol electrooxidation reaction. The peculiarities in electrochemical behavior of the synthesized Pt/(SnO₂/C)-electrocatalyst can be explained by the SnO₂ nanoparticle effect on the platinum nanoparticle nucleation/growth, as well as presence of Pt–SnO₂–C triple junction nanostructure at the surface. The Pt/SnO₂ contact provides stable platinum-to-support adhesion and asserts bifunctional catalysis mechanism of the methanol electrooxidation. And the Pt/C junctions provide for electron supplying/retraction to or from the platinum nanoparticles.