An Lin

Comparison of the performances of Ti/SnO2-Sb, Ti/SnO2-Sb/PbO2, and Nb/BDD anodes on electrochemical degradation of azo dye

In this paper, the preparation conditions of antimony-doped SnO2 and PbO2 electrode were optimized for the degradation activity of AO7 dye solution. The results showed that when the doping content of Sb is 8 mol %(SnO2-Sb(0.08)), the SnO2 electrode exhibited best activities for the decolorization and mineralization of AO7. The concentration of NaF in electroplating solution had a noticeable effect on PbO2 electrode for the decolorization of AO7 solution, but little influence on the COD removal rate. The anodic stability tests showed that the electrode prepared in the solution containing 0.10 g l−1 NaF (PbO2-F(0.10)) was best for environmental application. The comparison of SnO2-Sb(0.08), PbO2-F(0.10) and Boron-doped Diamond (BDD) electrodes revealed that a more rapid decolorization rate was obtained on SnO2-Sb(0.08) and PbO2-F(0.10) electrodes in dilute AO7 solutions, while higher COD removal rate of concentrated AO7 solutions was on BDD and SnO2-Sb(0.08) electrodes. The effect of concentration of Na2SO4 on the degradation rate of AO7 was very notable on BDD electrode for its highest overpotential of oxygen evolution reaction. In the chloride-containing medium, the decolorization was accelerated greatly but the completed mineralization of AO7 was inhibited with the increasing of chloride ions concentration when these high-overvoltage anodes were used

PbO(2)-SnO(2) composite anode with interconnected structure for the electrochemical incineration of phenol

A PbO2-SnO2 composite anode with interconnected structure is prepared for organics electro-incineration through a two-step method, thermal-decomposition process and subsequent low-current density electrodeposition process. The element mapping, together with the impedance spectra of the composite electrode, confirms that an interconnected architecture of SnO2 and PbO2 grains, instead of a lamellar structure, was obtained on the Ti substrate. A lower electrodeposition current density (≤10 mA cm−2) is very crucial for the formation of a porous surface and an interconnected architecture of two oxides inside. The asprepared electrode exhibits an enhanced electrocatalytic activity on the mineralization of phenol and a long service life due to the interconnected architecture, which helps to utilize the merits of these two metal oxides simultaneously. This two-step method also provides us a novel and facile way to fabricate a series of composite material such as oxide-oxide, oxide-metal composite electrodes.

Enhanced electrochemical oxidation of phenol by introducing ferric ions and UV radiation

The mineralization of phenol in aerated electrochemical oxidation has been investigated. The results show that a cathodic Fenton process can occur when the Ti-0.3Mo-0.8Ni alloy material is used as cathode in solution containing ferric or ferrous ions; moreover, the reinforcement of cathodic Fenton process on the total organic carbon (TOC) removal rate of phenol is quite distinct. Among the metallic ions investigated, the ferric ion is the best catalyst for the electrochemical mineralization of phenol at initial pH 2.0, and the optimal concentration range is from 50 to 200 mg/L. The favorable pH range and supporting electrolyte (Na2SO4) concentration for mineralization of phenol in solution containing ferrous ions are 1.8-2.3 and below 0.10 mol/L, respectively. UV radiation can improve the TOC removal rate of phenol, but the enhanced effect varies in different solutions. In the solution containing ferric ions, an equal sum or synergetic effect can be observed. The optimal effect of electrolysis system under UV radiation is achieved in the solution containing 50 mg/L Fe3+ with a final removal percentage of 81.3%.

Study of an environment‐friendly insulating coating with high corrosion resistance on electrical steel

[Lin, An; Zhang, Xian; Fang, Dajing; Yang, Miao; Gan, Fuxing] Wuhan Univ, Sch Resource & Environm Sci, Dept Environm Engn, Wuhan 430072, Peoples R China. [Gan, Fuxing] State Key Lab Corros & Protect Met, Shenyang, Peoples R China.;Lin, A (reprint author), Wuhan Univ, Sch Resource & Environm Sci, Dept Environm Engn, Wuhan 430072, Peoples R China;linanwd@126.com

Effect of organophosphorus pesticide on the corrosion of carbon steel in polluted freshwaters

Purpose - The aim of this paper is to study the corrosion behavior and corrosion mechanism of carbon steel in polluted freshwaters with organophosphorus pesticide (OP). Design/methodology/approach - The weight-loss method, electrochemical measurements and surface analysis technique were used to study the corrosion of carbon steel in polluted freshwaters with OP. Findings - General corrosion occurred when carbon steels were exposed to test solutions (freshwaters with and without OP). The presence of OP in test solutions can accelerate the corrosion rate of carbon steel. Originality/value - The aim of this work was to evaluate the effect of a single OP (diethylphosphite) on the corrosion of carbon steel. Until now, there was little research to report on this aspect. it was found that the presence of diethylphosphite at low concentrations could accelerate the corrosion rate of carbon steel in freshwaters. This research not only can offer theoretical guidelines for the prevention of pipelines and facilities from corroding, but also can provide reference for suitable material selection.