A novel anions and cations co-doped strategy for developing high-performance cobalt-free cathode for intermediate-temperature proton-conducting solid oxide fuel cells

The sluggish activity of cathode at intermediate-temperature limits commercialization of proton-conducting solid oxide fuel cells (H-SOFCs). In this investigation, a novel cathode of Ba_0.95Ca_0.05Fe_0.85Sn_0.05Y_0.1O_2.9−δF_0.1 was successfully developed by co-doping of anion F and cations Ca, Sn, Y. We studied the effect of F⁻-doping on phase structure, electrical conductivity and electrochemical properties of the cell. Compared with Ba_0.95Ca_0.05Fe_0.85Sn_0.05Y_0.1O_3−δ, F⁻-doped Ba_0.95Ca_0.05Fe_0.85Sn_0.05Y_0.1O_3−δ exhibited higher conductivity. Composite cathode consisting of Ba_0.95Ca_0.05Fe_0.85Sn_0.05Y_0.1O_2.9−δF_0.1 and Sm_0.2Ce_0.8O_2−δ was applied in H-SOFCs with BaZr_0.1Ce_0.7Y_0.2O_3−δ electrolyte which achieves an encouraging performance with the maximum power density of 1050 mW cm⁻² and polarization resistance of 0.04 Ω cm² at 700 °C. The result of First-principles calculations based on spin-polarized Density Functional Theory shows that doping of F⁻ reduces the activation energy required for migration of oxygen ions. These results demonstrate that the anions and cations co-doped strategy can provide a new horizon for the cathode in H-SOFCs.     

烷基季铵阳离子改性制备有机粘土的研究及应用进展

蒙脱石是属于2∶1型层状硅酸盐类粘土矿物,具有优异的物理化学性能。近年来,烷基季铵盐改性的有机膨润土作为一种新型的化学、化工原料在环境保护和新材料等应用方面引起了广泛的关注并且已成为当前材料科学的研究热点之一。本文概括了蒙脱石、烷基季铵盐的结构特征;阐述了有机膨润土的制备原理及合成工艺;介绍了有机蒙脱石的表征技术和现阶段研究成果;最后对有机粘土应用及发展前景进行了概述和展望。     

Polymeric compounds in activated sludge supernatant -- Characterisation and retention mechanisms at a full-scale municipal membrane bioreactor

In this study, for the first time a full-scale membrane bioreactor (MBR) was investigated with focus on organic compounds in activated sludge over a period of approximately 2 years. Soluble extracellular polymeric substances (EPS) in the sludge supernatant and permeate as well as bound EPS extracted from fouled membranes were determined photospectrometrically and revealed a typical composition of three main components in the order metals>humic acids>carbohydrates>proteins. Results showed an important influence on membrane fouling by soluble humic substances and carbohydrates in complexes with metal cations. It was found that Fe(2+) and Fe(3+) play a decisive role in natural organic matter (NOM) complexation and subsequent membrane blockage. The determination of molar mass distribution in supernatant and permeate by size exclusion chromatography (SEC) revealed a significant retention of macromolecular compounds by the porous membranes in the range of 10-50%.     

BMA—IL型平板玻璃防霉液的研制

根据我们曾提出的玻璃表面的电势在水对玻璃侵蚀过程中可以有效屏蔽离子交换、降低离子交换速率的机理,用复合高价阳离子金属盐与弱酸混合制备了BMA-IL型玻璃防霉液.实验证明,该防霉液可以有效地延缓玻璃表面霉变,将有很大的应用前景.     

Polymer brush coatings for combating marine biofouling

A variety of functional polymer brushes and coatings have been developed for combating marine biofouling and biocorrosion with much less environmental impact than traditional biocides. This review summarizes recent developments in marine antifouling polymer brushes and coatings that are tethered to material surfaces and do not actively release biocides. Polymer brush coatings have been designed to inhibit molecular fouling, microfouling and macrofouling through incorporation or inclusion of multiple functionalities. Hydrophilic polymers, such as poly(ethylene glycol), hydrogels, zwitterionic polymers and polysaccharides, resist attachment of marine organisms effectively due to extensive hydration. Fouling release polymer coatings, based on fluoropolymers and poly(dimethylsiloxane) elastomers, minimize adhesion between marine organisms and material surfaces, leading to easy removal of biofoulants. Polycationic coatings are effective in reducing marine biofouling partly because of their good bactericidal properties. Recent advances in controlled radical polymerization and click chemistry have also allowed better molecular design and engineering of multifunctional brush coatings for improved antifouling efficacies.     

Ion Exchange Technology in Spent Fuel Reprocessing

Solvent extraction is the major unit operation employed in spent nuclear fuel reprocessing. The operation yields three streams; fission product waste, uranium product and plutonium product. Ion exchange is primarily used in reprocessing as a tail-end method to concentrate and isolate the plutonium product stream. This review will describe the details of plutonium recovery and purification by both cation- and anion-exchange processing. A brief overview of miscellaneous uses of ion-exchange employed in reprocessing will also be given.     

Affinity of Cation-Exchange Membranes Towards Metallic Cations: Application in Continuous Electropermutation

The objective of this work was to correlate the separation process of the metallic cations (M(II)) by electropermutation (EP) of multications solution with the affinity of ion-exchange materials (IEMs). The obtained results show that the affinity order is similar for all tested IEMs and is as follows: Pb(II)>Cd(II)>Zn(II)>Mg(II). Furthermore, the order of the transfer flux (J) of metallic cations obtained with different tested cation-exchange membranes (CEMs) is identical to that encountered for the affinity order. Further analysis of the results demonstrated that the affinity of IEMs and the transfer flux change in reverse order of hydration ionic radius (r) of metallic cations: r_Mg(II)>r_Zn(II)≥r_Cd(II)>r_Pb(II). During the EP, the order of metallic cations transfer is as established previously when using different electro-regeneration cations (H⁺, Na⁺, NH₄⁺) and different co-ions (NO₃^?, Cl^?_, SO₄^2?). However, the extent of the transfer flux as a function of the nature of electro-regeneration cation follows the order: J_M(II)(H⁺)>J_M(II)(NH₄⁺)>J_M(II)(Na⁺). The removal rates of metallic cations vary in the range 89?99%. This work shows that the orders of the IEMs affinity and the transfer are mainly determined by the properties of metallic cations such as the hydration ionic radius. Nevertheless, the importance of the fixation and the transfer of metallic cations depend on the IEMs’ nature.     

沸石微波改性及其处理重金属离子电镀废水试验研究

针对电镀废水对生态环境的严重污染问题,采用微波辐射技术和Na Cl对天然沸石进行活化改性,并用以处理含重金属离子的电镀废水。在静态条件下,分析改性微波辐射功率、辐射时间、反应温度、反应时间、p H值、沸石用量及粒度对重金属离子去除率的影响。结果表明:选取粒度为0.15~0.18mm的沸石,于490W微波功率下辐射6min,制备微波改性沸石。在反应温度为40℃、p H值为6、吸附处理时间为30min、微波改性沸石投加量为8.0g/L时,改性沸石处理电镀废水中的金属离子的效果最好,电镀废水中Cu2+、Zn2+、Ni2+的去除率均达93.6%以上。