Synthesis of novel copper ion-selective material based on hierarchically imprinted cross-linked poly(acrylamide-co-ethylene glycol dimethacrylate)

A novel hierarchically imprinted cross-linked poly(acrylamide-co-ethylene glycol dimethacrylate) using a double-imprinting approach for the Cu²⁺ selective separation from aqueous medium was prepared. In the imprinting process, both Cu²⁺ ions and surfactant micelles (cetyltrimethylammonium bromide – CTAB) were employed as templates. The hierarchically imprinted organic polymer named (IIP-CTAB), single-imprinted (IIP-no CTAB) and non-imprinted (NIP-CTAB and NIP-no CTAB) polymers were characterized by SEM, FTIR, TG, elemental analysis and textural data from BET (Brunauer–Emmett–Teller) and BJH (Barrett–Joyner–Halenda). Compared to these materials, IIP-CTAB showed higher selectivity, specific surface area and adsorption capacity toward Cu²⁺ ions. Good selectivity for Cu²⁺ was obtained for the Cu²⁺/Cd²⁺, Cu²⁺/Zn²⁺ and Cu²⁺/Co²⁺ systems when IIP-CTAB was compared to the single-imprinted (IIP-no CTAB) and non double-imprinted polymer (NIP-CTAB), thereby confirming the improvement in the polymer selectivity due to double-imprinting effect. For adsorption kinetic data, the best fit was provided with the pseudo-second-order model for the four materials, thereby indicating the chemical nature of the Cu²⁺ adsorption process. Cu²⁺ adsorption under equilibrium was found to follow dual-site Langmuir–Freundlich model isotherm, thus suggesting the existence of adsorption sites with low and high binding energy on the adsorbent surface. From column experiments 600 adsorption–desorption cycles using 1.8 mol L⁻¹ HNO₃ as eluent confirmed the great recoverability of adsorbent. The synthesis approach here investigated has been found to be very attractive for the designing of organic ion imprinted polymer and can be expanded to the other polymers to improve performance of ion imprinted polymers in the field of solid phase extraction.     

Three-dimensionally ordered macroporous polyimide composite membrane with controlled pore size for direct methanol fuel cells

Three-dimensionally ordered macroporous (3DOM) polyimide matrix with different pore size (1.3 μm–200 nm) was fabricated, and its structural effect on some properties of composite membrane was investigated. The composite membrane prepared by impregnation of 2-acrylamido-2-methylpropanesulfonic acid polymer (PAMPS) exhibited swelling ratios as low as 2–3% in water or methanol solutions, compared with about 400% of PAMPS itself. The swelling ratio of composite membrane was constant regardless of the 3DOM pore size. However, methanol permeability strongly depended on the pore size. In particular, it was drastically reduced when connecting windows among macropores became less than 100 nm. On the other hand, proton conductivity changed with 3DOM matrix porosity according to Archie's law. The porosity of 3DOM matrix is basically constant even if the pore size changes. Therefore, we suppressed the methanol crossover without lowering of proton conductivity due to reducing the matrix pore size, and the selectivity (proton conductivity/methanol permeability) of 1.2 × 10⁵ S cm⁻³ s, which was one order of magnitude greater than that of Nafion^®, was achieved.     

连续反应技术在柑青醛生产中的应用研究

本文通过对多种不同类型连续反应装置的结构性能进行比较研究,探索连续反应装置结构类型及尺寸参数与反应产物选择性之间的关系,最终设计出一套理想的柑青醛连续生产工艺(反应装置),从而实现降低能耗50%、提高产物收率13%、质量达到国外产品同等水平、降低生产成本20%。     

催化汽油选择性加氢脱硫技术OCT-MD的工业应用

介绍了抚顺石油化工研究院开发的OCT-MD催化裂化汽油选择性加氢脱硫技术的特点及其在镇海炼化分公司0.7 Mt/a OCT-MD装置进行工业应用的情况。标定结果表明,FCC汽油的含硫质量分数由308～483μg/g降低到50μg/g左右,RON损失0.4～0.8个单位,工业应用是成功的,取得了较好的效果。     

Computational study of CO2 methanation over two-dimensional molybdenum carbide catalysts

Two-dimensional molybdenum carbide (2D-Mo₂C) is thought to be promising for catalytic hydrogenation of CO₂ to CH₄, but little is known about its catalytic reaction mechanism. In this work, we investigate the hydrogenation of CO₂ to CH₄ on 2D-Mo₂C using density functional theory. Our calculations show that Mo on the surface can efficiently decompose CO₂ to CO and O, and also H₂ to H. The hydrogenation of CO produces CHO that is readily deoxygenated to CH, and CH is selectively hydrogenated to produce CH₄. Interestingly, the embedded Ir₁ on 2D-Mo₂C can act as a single-atom promoter to improve the performance of CO₂ methanation, while on the other hand maintaining its high selectivity for CH₄. This work provides insight into the mechanism of 2D-Mo₂C-catalyzed CO₂ methanation reactions and suggests a strategy to improve the performance of such catalysts through single-atom promoters.     

弱碱性介质中提高永平铜矿铜金银回收率的研究

T 2K捕收剂与黄铜矿形成正配键和反馈键的能力很强,而与黄铁矿的作用弱。工业试验结果表明,T 2K捕收剂对硫化铜矿物具有优异的捕收能力和选择性,能在弱碱性介质中实现铜的优先浮选,克服黄药混浮工艺铜硫分离时高碱对部分铜、金、银的抑制。与黄药混浮工艺相比,T 2K全优先浮选工艺使铜精矿品位提高0 42%,铜回收率提高2 54%;硫精矿品位提高1 37%,硫回收率提高4 17%;铜精矿中金银回收率也分别提高3 73%和5 73%。     

Selectivity study of the differential impedance analysis—comparison with the complex non-linear least-squares method

The analytical power of the differential impedance analysis (DIA) as a new approach for model identification is investigated. The minimum of the ratio q of the two time-constants T₁ and T₂ (q=T₂/T₁) describing a two step reaction with ladder structure, at which the second time-constant T₂ is recognized, is accepted as a measure for the selectivity evaluation. The investigation is performed on synthetic models with variation of q in the interval from 30 to 0.001. The influence of data quality is studied by applying data truncation from seven to two digits, as well as by introduction of a wild point. Experimental data measured on two actual dummy cells with q equal to 30 and 0.03, respectively, are also analyzed. The results are compared with those obtained by applying the algorithm of the wide-spread complex non-linear least-squares method, performed on zview software product. The comparative study demonstrates a higher selectivity of the DIA, combined with an additional noise immunity and increased robustness of the analysis.     

Stator winding single-phase grounding faults protective scheme based on discriminant analysis for Powerformers with selectivity

In order to improve the stator winding single-phase grounding faults protective scheme for Powerformers, a protective scheme based on Mahal distance discriminant theory is proposed in this paper. By the proposed scheme, the different kinds of fault signals can be integrated. Also, a discriminant analysis model for stator winding single-phase grounding faults is established. In the proposed discriminant analysis model, four parameters including the magnitude of leakage current, the direction of leakage current, the magnitude of zero-sequence current in Powerformer terminal, and the direction of zero-sequence current in Powerformer terminal are selected as the discrimination factor. The method of back substitution estimation is introduced to verify the stability of the distance discriminant analysis model. Twenty-five groups of detected samples were analyzed based on the proposed model. The results are consistent with the measured data and show that the distance discriminant analysis model is with higher accuracy and lower mistake-discrimination ratio.     

Liquid‐Phase Aerobic Oxidation of Benzyl Alcohol Catalyzed by Pt/ZrO2

The oxidation of benzyl alcohol by molecular oxygen in the liquid phase and catalyzed by Pt/ZrO2 using n‐heptane as the solvent was studied. Pt/ZrO₂ was very active and 100 % selective for benzyl alcohol conversion to benzaldehyde. The catalyst can be separated by filtration and reused. No leaching of Pt or Zr into the solution was observed. Typical batch reactor kinetic data were obtained and fitted to the Langmuir‐Hinshelwood, Eley‐Rideal and Mars‐van Krevelen models of heterogeneously catalyzed reactions. The Langmuir‐Hinshelwood model was found to give a better fit. The rate‐determining step was proposed to involve direct interaction of an adsorbed oxidizing species with the adsorbed reactant or an intermediate product of the reactant. H₂O₂ was also proposed to be an intermediate product. n‐Heptane was found to be an appropriate solvent in this reaction system.     

新型高选择性汽油敏感元件

报道了一种新型高选择性汽油敏感元件，该元件采用互补反馈原理及实现该原理的元件结构（Ｎ—Ｎ型结构），提高了元件的选择性，同时还具有良好的抗环境温、湿度的能力。