Wet Oxidation Treatment of Radioactive Spent Ion-Exchange Resin

Radioactive waste ion-exchange resins have been treated by cement solidification directly, however, the effect of cement is unsatisfactory. In order to find other proper treatment methods, many investigations have been carried out. Especially, wet oxidation treatment technology is favored by many researchers because of its short treatment cycle and high volume reduction ratio. In this work, the reaction mechanism, process characteristics and industrial application of the wet oxidation treatment of radioactive spent ion-exchange resins were summarized. The analysis of the acid boiling degradation, Fenton wet oxidation technology, steam reforming process and supercritical water oxidation method had been focused. Mainly for the acid digestion, steam reforming process, supercritical water oxidation and Fenton wet oxidation were compared by the status of research at home and abroad and industrial applications, combined with the advantages and disadvantages of each method and the ease of post-processing,and considering the perspective of nuclear safety and convenient for subsequent processing, four treatment methods were briefly analyzed by comparing the advantages and disadvantages of each method. The results indicated that Fenton wet oxidation treatment of radioactive spent ion exchange resin was one of the feasible schemes.     

Implementation of ZnSnO3 nanosheets and their RE (Er,Eu, and Pr) materials: Enhanced photocatalytic activity

ZnSnO₃, ZnSnO₃@Er, ZnSnO₃@Eu, and ZnSnO₃@Pr materials were synthesized by a hydrothermal method, these active materials characterized by XRD, Raman, DRS-UV, FT-IR, BET surface areas and Scanning electron microscopy studies. The ZnSnO₃ nanosheets meta-stable form was confirmed by XRD. Here, addressing to the pure and doped materials functional groups were evaluated by FT-IR spectroscopy. ZnSnO₃, ZnSnO₃@Er, ZnSnO₃@Eu, and ZnSnO₃@Pr rotational vibrations frequency modes were predicted by the Raman spectroscopy. Our results are marvelously, the obtained bandgap energies at 3.5 eV for pure sample and ZnSnO₃@Er, ZnSnO₃@Eu and ZnSnO₃@Pr energies at 3.06 eV, 3.04 eV and 3.02 eV. The synthesized pure samples get a sheet-like morphology and doped for RE metals than morphology was changing for nanocubes. We assess for all samples that were focused on photocatalytic dye degradation for Methylene blue dye; hence, we are discussing these approaches, ZnSnO₃@Pr/Methylene blue sample was a great improvement and high decolorization efficiency compared with ZnSnO₃@Er, ZnSnO₃@Eu nanocubes. The ZnSnO₃@Pr sample surface area was investigated by BET analysis. In addition, we are testing the phenol degradation with wastewater. The ZnSnO₃@Er, ZnSnO₃@Eu catalysts were determined to the less efficiency when comparing to the ZnSnO₃@Pr material. The ZnSnO₃@Pr material results have more efficiency and a very good recyclable stability nature.     

Metallurgical slag properties as a support material for bimetallic nanoparticles and their use in the removal of malachite green dye

Fe-Cu oxides nanoparticles (Nps) were embedded in two steel slag wastes (SSB and SSW) to develop SSB/Fe-Cu and SSW/Fe-Cu nanocomposites. Nps with mean sizes between 10–20 and 6–10 nm on SSW and SSB, respectively are agglomeration with a different shape. Their characteristics were investigated by XRD, TEM, BET, SEM techniques. The Nps modified the morphology of both support materials. XRD pointed out the presence of Cu and Fe. The proportion of Cu concentration was higher than the one of Fe. Nanocomposites were tested in malachite green removal from aqueous solution. The adsorption kinetic indicated physisorption and chemisorption as the main mechanisms of adsorption. The adsorption capacities were 88.26 and 63.55 mg/g for SSW/Fe-Cu and SSB/Fe-Cu, respectively. This novel, easy to prepare and low-cost nanocomposites is an efficient adsorbent material. The presence of calcium compounds may improve Nps deposition an MG removal. Materials with ferric phases are not as efficient as the first one; Fe is not well supported on the material. The removal of MG took place by dye structure modification and by interactions with Cu nanoparticles improving the oxidation-reduction process, through synergic effects.     

Chemistry of SiNx thin film deposited by plasma-enhanced atomic layer deposition using di-isopropylaminosilane (DIPAS) and N2 plasma

Silicon nitride (Si₃N₄) films have received great attention not only as dielectric materials for the gate dielectric of transistors and the insulator of capacitors, but also as a buffer layer and etch-stop layer for the semiconductor industry. As the applications of Si₃N₄ film increase, the necessity of investigating a novel deposition process applicable at low temperature has emerged. In this regard, the plasma-enhanced atomic layer deposition (PEALD) technique is attractive as a promising process; however, the Si₃N₄ film deposition process at growth temperatures less than 150?°C using PEALD has not been investigated. In this work, the growth behavior and chemistry of SiN_x (x?<?1.33) film deposited by the PEALD process at various growth temperatures were developed. Insufficient thermal energy from low growth temperature induces an unstable chemical state of deposited film due to the remaining unreacted ligand of adsorbed precursors. This state results in a further chemical reaction to SiO₂ formation by air exposure. Other chemical effects depending on chemical composition and electrical property were also examined in detail.     

Polymer Light Emitting Diodes: Materials,Technology and Device

Polymer Light Emitting Diodes (PLEDs), the most promising name in the field of display technology has received tremendous attention from various research groups. The research on light emitting polymers are an interdisciplinary zone which has challenging investigates on materials science and engineering, physics of device architecture and technology. This review addresses the wide range of tailored polymers, evolution of LED device structure for high performance, single and multicolor polymer based LEDs. Though, polymers are possessing better efficiency and easy fabrication processes, it has very low stability and short life. This study also reviews, device degradation during device fabrication and operation.     

Solar light-driven reduction of crystal violet by a composite of g-C3N4, β-Ag2Se, γ-Fe2O3 and graphite

Abstract

In this work, a new g-C₃N₄-based Z-scheme with γ-Fe₂O₃ and β-Ag₂Se both n-type semiconductors, and graphite to favor electron exchange is presented. The composite material was studied by XRD, FTIR, UV-Vis, TEM, XPS, TGA, DSC and TOF-SIMS, and the ability of this photocatalytic system to act as a photo-reductant was assessed using crystal violet (CV⁺) dye. Solar light driven photo-reduction of CV⁺ in the presence of tri-sodium citrate evidenced a synergistic enhancement of the activity of the composite toward reduction, with ～20 times higher conversion rates per unit of surface area than those of g-C₃N₄. Photo-oxidation experiments under Xe lamp irradiation in the presence of H₂O₂ also showed that the AgFeCN composite featured a higher activity (～8×) than g-C₃N₄. This Z-scheme may deserve further study as a photo-reductant to obtain hydrogen or hydrogenated compounds. Moreover, the use of CV⁺ may represent a facile procedure that can aid in the selection of new photocatalysts to be used in hydrogen production.     

基于阳极氧化法的TiO2纳米管制备及生成过程分析

运用阳极氧化法制备TiO₂纳米管，探讨了TiO₂纳米管紫外光催化净化头孢噻肟钠抗生素废水的效果，采用扫描电镜（SEM）和X射线衍射仪（XRD）对TiO₂纳米管进行了表征分析。SEM结果显示，制备的TiO₂材料表面呈阵列排布的多孔状，内径大小均匀，管径分布在30~45nm之间，管阵列呈蜂窝状，与钛板表面垂直，对比煅烧前后的TiO₂纳米管XRD图，发现煅烧后样品的XRD图出现了TiO₂锐钛矿型特征衍射峰和金红石型特征衍射峰。讨论了TiO₂纳米管的生成机理，认为纳米管的形成过程主要有最初氧化层的形成、孔核的形成、由孔核演变成微孔、微孔生长并出现空隙、形成纳米阵列管过程。