Laboratory experiments were carried out on the kinetics and pathways of the electrochemical (EC) degradation of phenol at three different types of anodes, Ti/SnO2-Sb, Ti/RuO2, and Pt. Although phenol was oxidised by all of the anodes at a current density of 20 mA/cm2 or a cell voltage of 4.6 V, there was a considerable difference between the three anode types in the effectiveness and performance of EC organic degradation. Phenol was readily mineralized at the Ti/SnO2-Sb anode, but its degradation was much slower at the Ti/RuO2 and Pt anodes. The analytical results of high-performance liquid chromatography (HPLC) and gas chromatography coupled with mass spectrometry (GC/MS) indicated that the intermediate products of EC phenol degradation, including benzoquinone and organic acids, were subsequently oxidised rapidly by the Ti/SnO2-Sb anode, but accumulated in the cells of Ti/RuO2 and Pt. There was also a formation of dark-coloured polymeric compounds and precipitates in the solutions electrolyzed by the Ti/RuO2 and Pt anodes, which was not observed for the Ti/SnO2-Sb cells. It is argued that anodic property not only affects the reaction kinetics of various steps of EC organic oxidation, but also alters the pathway of phenol electrolysis. Favourable surface treatment, such as the SnO2-Sb coating, provides the anode with an apparent catalytic function for rapid organic oxidation that is probably brought about by hydroxyl radicals generated from anodic water electrolysis.

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A novel green/biodegradable adsorbent, mungbean-coat, has been investigated for the adsorption of ultra-trace amounts of cadmium. Carboxylic groups on the bean-coat effectively retain the cadmium ions via coordinative interactions. This well facilitates the adsorption of cadmium ions which can readily be recovered by acid elution. In practice, bean-coat is used to pack a mini-column for on-line adsorption and preconcentration of cadmium from environmental samples with detection by electrothermal atomic absorption spectrometry. By using a sample loading volume of 1.4 mL and an eluent volume of 70 mL, an enrichment factor of 19.8 along with a detection limit of 1.4 ng L À1 are achieved. A precision of 2.4% RSD at the level of 0.05 mg L À1 is derived. The present procedure has been applied for the determination of cadmium in certified reference materials (GBW08608 Trace Elements in Water and CRM 176 Trace Elements in a City Waste Incineration Ash) and a snow water sample. Fair agreements are reached between the certified values and the experimental results, in addition to a satisfactory spiking recovery for the snow water sample. In the present work, the use of green and biodegradable adsorbent as well as the elimination of use of organic solvent/eluent facilitates the development of a green analytical protocol.

Cu samples were subjected to high-pressure torsion (HPT) with up to 6 turns at room temperature (RT) and liquid nitrogen temperature (LNT), respectively. The effects of temperature on grain refinement and microhardness variation were investigated. For the samples after HPT processing at RT, the grain size reduced from 43 μm to 265 nm, and the Vickers microhardness increased from HV52 to HV140. However, for the samples after HPT processing at LNT, the value of microhardness reached its maximum of HV150 near the center of the sample and it decreased to HV80 at the periphery region. Microstructure observations revealed that HPT straining at LNT induced lamellar structures with thickness less than 100 nm appearing near the central region of the sample, but further deformation induced an inhomogeneous distribution of grain sizes, with submicrometer-sized grains embedded inside micrometer-sized grains. The submicrometer-sized grains with high dislocation density indicated their nonequilibrium nature. On the contrary, the micrometer-sized grains were nearly free of dislocation, without obvious deformation trace remaining in them. These images demonstrated that the appearance of micrometer-sized grains is the result of abnormal grain growth of the deformed fine grains. copper, high pressure torsion (HPT), microstructure, grain size, microhardness, cryogenic temperature Citation:Xie Z L, Xie J J, Hong Y S, et al. Influence of processing temperature on microstructure and microhardness of copper subjected to high-pressure torsion.